--- old/usr/src/uts/common/os/kmem.c
          +++ new/usr/src/uts/common/os/kmem.c

   1    1  /*
   2    2   * CDDL HEADER START
   3    3   *
   4    4   * The contents of this file are subject to the terms of the
   5    5   * Common Development and Distribution License (the "License").
   6    6   * You may not use this file except in compliance with the License.
   7    7   *
   8    8   * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9    9   * or http://www.opensolaris.org/os/licensing.
  10   10   * See the License for the specific language governing permissions
  11   11   * and limitations under the License.
  12   12   *
  13   13   * When distributing Covered Code, include this CDDL HEADER in each
  14   14   * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15   15   * If applicable, add the following below this CDDL HEADER, with the
  16   16   * fields enclosed by brackets "[]" replaced with your own identifying
  17   17   * information: Portions Copyright [yyyy] [name of copyright owner]
  18   18   *
  19   19   * CDDL HEADER END
  20   20   */
  21   21  /*
  22   22   * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
  23   23   * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
  24   24   * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
  25   25   * Copyright 2018, Joyent, Inc.
  26   26   * Copyright 2023 Oxide Computer Company
  27   27   */
  28   28  
  29   29  /*
  30   30   * Kernel memory allocator, as described in the following two papers and a
  31   31   * statement about the consolidator:
  32   32   *
  33   33   * Jeff Bonwick,
  34   34   * The Slab Allocator: An Object-Caching Kernel Memory Allocator.
  35   35   * Proceedings of the Summer 1994 Usenix Conference.
  36   36   * Available as /shared/sac/PSARC/1994/028/materials/kmem.pdf.
  37   37   *
  38   38   * Jeff Bonwick and Jonathan Adams,
  39   39   * Magazines and vmem: Extending the Slab Allocator to Many CPUs and
  40   40   * Arbitrary Resources.
  41   41   * Proceedings of the 2001 Usenix Conference.
  42   42   * Available as /shared/sac/PSARC/2000/550/materials/vmem.pdf.
  43   43   *
  44   44   * kmem Slab Consolidator Big Theory Statement:
  45   45   *
  46   46   * 1. Motivation
  47   47   *
  48   48   * As stated in Bonwick94, slabs provide the following advantages over other
  49   49   * allocation structures in terms of memory fragmentation:
  50   50   *
  51   51   *  - Internal fragmentation (per-buffer wasted space) is minimal.
  52   52   *  - Severe external fragmentation (unused buffers on the free list) is
  53   53   *    unlikely.
  54   54   *
  55   55   * Segregating objects by size eliminates one source of external fragmentation,
  56   56   * and according to Bonwick:
  57   57   *
  58   58   *   The other reason that slabs reduce external fragmentation is that all
  59   59   *   objects in a slab are of the same type, so they have the same lifetime
  60   60   *   distribution. The resulting segregation of short-lived and long-lived
  61   61   *   objects at slab granularity reduces the likelihood of an entire page being
  62   62   *   held hostage due to a single long-lived allocation [Barrett93, Hanson90].
  63   63   *
  64   64   * While unlikely, severe external fragmentation remains possible. Clients that
  65   65   * allocate both short- and long-lived objects from the same cache cannot
  66   66   * anticipate the distribution of long-lived objects within the allocator's slab
  67   67   * implementation. Even a small percentage of long-lived objects distributed
  68   68   * randomly across many slabs can lead to a worst case scenario where the client
  69   69   * frees the majority of its objects and the system gets back almost none of the
  70   70   * slabs. Despite the client doing what it reasonably can to help the system
  71   71   * reclaim memory, the allocator cannot shake free enough slabs because of
  72   72   * lonely allocations stubbornly hanging on. Although the allocator is in a
  73   73   * position to diagnose the fragmentation, there is nothing that the allocator
  74   74   * by itself can do about it. It only takes a single allocated object to prevent
  75   75   * an entire slab from being reclaimed, and any object handed out by
  76   76   * kmem_cache_alloc() is by definition in the client's control. Conversely,
  77   77   * although the client is in a position to move a long-lived object, it has no
  78   78   * way of knowing if the object is causing fragmentation, and if so, where to
  79   79   * move it. A solution necessarily requires further cooperation between the
  80   80   * allocator and the client.
  81   81   *
  82   82   * 2. Move Callback
  83   83   *
  84   84   * The kmem slab consolidator therefore adds a move callback to the
  85   85   * allocator/client interface, improving worst-case external fragmentation in
  86   86   * kmem caches that supply a function to move objects from one memory location
  87   87   * to another. In a situation of low memory kmem attempts to consolidate all of
  88   88   * a cache's slabs at once; otherwise it works slowly to bring external
  89   89   * fragmentation within the 1/8 limit guaranteed for internal fragmentation,
  90   90   * thereby helping to avoid a low memory situation in the future.
  91   91   *
  92   92   * The callback has the following signature:
  93   93   *
  94   94   *   kmem_cbrc_t move(void *old, void *new, size_t size, void *user_arg)
  95   95   *
  96   96   * It supplies the kmem client with two addresses: the allocated object that
  97   97   * kmem wants to move and a buffer selected by kmem for the client to use as the
  98   98   * copy destination. The callback is kmem's way of saying "Please get off of
  99   99   * this buffer and use this one instead." kmem knows where it wants to move the
 100  100   * object in order to best reduce fragmentation. All the client needs to know
 101  101   * about the second argument (void *new) is that it is an allocated, constructed
 102  102   * object ready to take the contents of the old object. When the move function
 103  103   * is called, the system is likely to be low on memory, and the new object
 104  104   * spares the client from having to worry about allocating memory for the
 105  105   * requested move. The third argument supplies the size of the object, in case a
 106  106   * single move function handles multiple caches whose objects differ only in
 107  107   * size (such as zio_buf_512, zio_buf_1024, etc). Finally, the same optional
 108  108   * user argument passed to the constructor, destructor, and reclaim functions is
 109  109   * also passed to the move callback.
 110  110   *
 111  111   * 2.1 Setting the Move Callback
 112  112   *
 113  113   * The client sets the move callback after creating the cache and before
 114  114   * allocating from it:
 115  115   *
 116  116   *      object_cache = kmem_cache_create(...);
 117  117   *      kmem_cache_set_move(object_cache, object_move);
 118  118   *
 119  119   * 2.2 Move Callback Return Values
 120  120   *
 121  121   * Only the client knows about its own data and when is a good time to move it.
 122  122   * The client is cooperating with kmem to return unused memory to the system,
 123  123   * and kmem respectfully accepts this help at the client's convenience. When
 124  124   * asked to move an object, the client can respond with any of the following:
 125  125   *
 126  126   *   typedef enum kmem_cbrc {
 127  127   *           KMEM_CBRC_YES,
 128  128   *           KMEM_CBRC_NO,
 129  129   *           KMEM_CBRC_LATER,
 130  130   *           KMEM_CBRC_DONT_NEED,
 131  131   *           KMEM_CBRC_DONT_KNOW
 132  132   *   } kmem_cbrc_t;
 133  133   *
 134  134   * The client must not explicitly kmem_cache_free() either of the objects passed
 135  135   * to the callback, since kmem wants to free them directly to the slab layer
 136  136   * (bypassing the per-CPU magazine layer). The response tells kmem which of the
 137  137   * objects to free:
 138  138   *
 139  139   *       YES: (Did it) The client moved the object, so kmem frees the old one.
 140  140   *        NO: (Never) The client refused, so kmem frees the new object (the
 141  141   *            unused copy destination). kmem also marks the slab of the old
 142  142   *            object so as not to bother the client with further callbacks for
 143  143   *            that object as long as the slab remains on the partial slab list.
 144  144   *            (The system won't be getting the slab back as long as the
 145  145   *            immovable object holds it hostage, so there's no point in moving
 146  146   *            any of its objects.)
 147  147   *     LATER: The client is using the object and cannot move it now, so kmem
 148  148   *            frees the new object (the unused copy destination). kmem still
 149  149   *            attempts to move other objects off the slab, since it expects to
 150  150   *            succeed in clearing the slab in a later callback. The client
 151  151   *            should use LATER instead of NO if the object is likely to become
 152  152   *            movable very soon.
 153  153   * DONT_NEED: The client no longer needs the object, so kmem frees the old along
 154  154   *            with the new object (the unused copy destination). This response
 155  155   *            is the client's opportunity to be a model citizen and give back as
 156  156   *            much as it can.
 157  157   * DONT_KNOW: The client does not know about the object because
 158  158   *            a) the client has just allocated the object and not yet put it
 159  159   *               wherever it expects to find known objects
 160  160   *            b) the client has removed the object from wherever it expects to
 161  161   *               find known objects and is about to free it, or
 162  162   *            c) the client has freed the object.
 163  163   *            In all these cases (a, b, and c) kmem frees the new object (the
 164  164   *            unused copy destination).  In the first case, the object is in
 165  165   *            use and the correct action is that for LATER; in the latter two
 166  166   *            cases, we know that the object is either freed or about to be
 167  167   *            freed, in which case it is either already in a magazine or about
 168  168   *            to be in one.  In these cases, we know that the object will either
 169  169   *            be reallocated and reused, or it will end up in a full magazine
 170  170   *            that will be reaped (thereby liberating the slab).  Because it
 171  171   *            is prohibitively expensive to differentiate these cases, and
 172  172   *            because the defrag code is executed when we're low on memory
 173  173   *            (thereby biasing the system to reclaim full magazines) we treat
 174  174   *            all DONT_KNOW cases as LATER and rely on cache reaping to
 175  175   *            generally clean up full magazines.  While we take the same action
 176  176   *            for these cases, we maintain their semantic distinction:  if
 177  177   *            defragmentation is not occurring, it is useful to know if this
 178  178   *            is due to objects in use (LATER) or objects in an unknown state
 179  179   *            of transition (DONT_KNOW).
 180  180   *
 181  181   * 2.3 Object States
 182  182   *
 183  183   * Neither kmem nor the client can be assumed to know the object's whereabouts
 184  184   * at the time of the callback. An object belonging to a kmem cache may be in
 185  185   * any of the following states:
 186  186   *
 187  187   * 1. Uninitialized on the slab
 188  188   * 2. Allocated from the slab but not constructed (still uninitialized)
 189  189   * 3. Allocated from the slab, constructed, but not yet ready for business
 190  190   *    (not in a valid state for the move callback)
 191  191   * 4. In use (valid and known to the client)
 192  192   * 5. About to be freed (no longer in a valid state for the move callback)
 193  193   * 6. Freed to a magazine (still constructed)
 194  194   * 7. Allocated from a magazine, not yet ready for business (not in a valid
 195  195   *    state for the move callback), and about to return to state #4
 196  196   * 8. Deconstructed on a magazine that is about to be freed
 197  197   * 9. Freed to the slab
 198  198   *
 199  199   * Since the move callback may be called at any time while the object is in any
 200  200   * of the above states (except state #1), the client needs a safe way to
 201  201   * determine whether or not it knows about the object. Specifically, the client
 202  202   * needs to know whether or not the object is in state #4, the only state in
 203  203   * which a move is valid. If the object is in any other state, the client should
 204  204   * immediately return KMEM_CBRC_DONT_KNOW, since it is unsafe to access any of
 205  205   * the object's fields.
 206  206   *
 207  207   * Note that although an object may be in state #4 when kmem initiates the move
 208  208   * request, the object may no longer be in that state by the time kmem actually
 209  209   * calls the move function. Not only does the client free objects
 210  210   * asynchronously, kmem itself puts move requests on a queue where thay are
 211  211   * pending until kmem processes them from another context. Also, objects freed
 212  212   * to a magazine appear allocated from the point of view of the slab layer, so
 213  213   * kmem may even initiate requests for objects in a state other than state #4.
 214  214   *
 215  215   * 2.3.1 Magazine Layer
 216  216   *
 217  217   * An important insight revealed by the states listed above is that the magazine
 218  218   * layer is populated only by kmem_cache_free(). Magazines of constructed
 219  219   * objects are never populated directly from the slab layer (which contains raw,
 220  220   * unconstructed objects). Whenever an allocation request cannot be satisfied
 221  221   * from the magazine layer, the magazines are bypassed and the request is
 222  222   * satisfied from the slab layer (creating a new slab if necessary). kmem calls
 223  223   * the object constructor only when allocating from the slab layer, and only in
 224  224   * response to kmem_cache_alloc() or to prepare the destination buffer passed in
 225  225   * the move callback. kmem does not preconstruct objects in anticipation of
 226  226   * kmem_cache_alloc().
 227  227   *
 228  228   * 2.3.2 Object Constructor and Destructor
 229  229   *
 230  230   * If the client supplies a destructor, it must be valid to call the destructor
 231  231   * on a newly created object (immediately after the constructor).
 232  232   *
 233  233   * 2.4 Recognizing Known Objects
 234  234   *
 235  235   * There is a simple test to determine safely whether or not the client knows
 236  236   * about a given object in the move callback. It relies on the fact that kmem
 237  237   * guarantees that the object of the move callback has only been touched by the
 238  238   * client itself or else by kmem. kmem does this by ensuring that none of the
 239  239   * cache's slabs are freed to the virtual memory (VM) subsystem while a move
 240  240   * callback is pending. When the last object on a slab is freed, if there is a
 241  241   * pending move, kmem puts the slab on a per-cache dead list and defers freeing
 242  242   * slabs on that list until all pending callbacks are completed. That way,
 243  243   * clients can be certain that the object of a move callback is in one of the
 244  244   * states listed above, making it possible to distinguish known objects (in
 245  245   * state #4) using the two low order bits of any pointer member (with the
 246  246   * exception of 'char *' or 'short *' which may not be 4-byte aligned on some
 247  247   * platforms).
 248  248   *
 249  249   * The test works as long as the client always transitions objects from state #4
 250  250   * (known, in use) to state #5 (about to be freed, invalid) by setting the low
 251  251   * order bit of the client-designated pointer member. Since kmem only writes
 252  252   * invalid memory patterns, such as 0xbaddcafe to uninitialized memory and
 253  253   * 0xdeadbeef to freed memory, any scribbling on the object done by kmem is
 254  254   * guaranteed to set at least one of the two low order bits. Therefore, given an
 255  255   * object with a back pointer to a 'container_t *o_container', the client can
 256  256   * test
 257  257   *
 258  258   *      container_t *container = object->o_container;
 259  259   *      if ((uintptr_t)container & 0x3) {
 260  260   *              return (KMEM_CBRC_DONT_KNOW);
 261  261   *      }
 262  262   *
 263  263   * Typically, an object will have a pointer to some structure with a list or
 264  264   * hash where objects from the cache are kept while in use. Assuming that the
 265  265   * client has some way of knowing that the container structure is valid and will
 266  266   * not go away during the move, and assuming that the structure includes a lock
 267  267   * to protect whatever collection is used, then the client would continue as
 268  268   * follows:
 269  269   *
 270  270   *      // Ensure that the container structure does not go away.
 271  271   *      if (container_hold(container) == 0) {
 272  272   *              return (KMEM_CBRC_DONT_KNOW);
 273  273   *      }
 274  274   *      mutex_enter(&container->c_objects_lock);
 275  275   *      if (container != object->o_container) {
 276  276   *              mutex_exit(&container->c_objects_lock);
 277  277   *              container_rele(container);
 278  278   *              return (KMEM_CBRC_DONT_KNOW);
 279  279   *      }
 280  280   *
 281  281   * At this point the client knows that the object cannot be freed as long as
 282  282   * c_objects_lock is held. Note that after acquiring the lock, the client must
 283  283   * recheck the o_container pointer in case the object was removed just before
 284  284   * acquiring the lock.
 285  285   *
 286  286   * When the client is about to free an object, it must first remove that object
 287  287   * from the list, hash, or other structure where it is kept. At that time, to
 288  288   * mark the object so it can be distinguished from the remaining, known objects,
 289  289   * the client sets the designated low order bit:
 290  290   *
 291  291   *      mutex_enter(&container->c_objects_lock);
 292  292   *      object->o_container = (void *)((uintptr_t)object->o_container | 0x1);
 293  293   *      list_remove(&container->c_objects, object);
 294  294   *      mutex_exit(&container->c_objects_lock);
 295  295   *
 296  296   * In the common case, the object is freed to the magazine layer, where it may
 297  297   * be reused on a subsequent allocation without the overhead of calling the
 298  298   * constructor. While in the magazine it appears allocated from the point of
 299  299   * view of the slab layer, making it a candidate for the move callback. Most
 300  300   * objects unrecognized by the client in the move callback fall into this
 301  301   * category and are cheaply distinguished from known objects by the test
 302  302   * described earlier. Because searching magazines is prohibitively expensive
 303  303   * for kmem, clients that do not mark freed objects (and therefore return
 304  304   * KMEM_CBRC_DONT_KNOW for large numbers of objects) may find defragmentation
 305  305   * efficacy reduced.
 306  306   *
 307  307   * Invalidating the designated pointer member before freeing the object marks
 308  308   * the object to be avoided in the callback, and conversely, assigning a valid
 309  309   * value to the designated pointer member after allocating the object makes the
 310  310   * object fair game for the callback:
 311  311   *
 312  312   *      ... allocate object ...
 313  313   *      ... set any initial state not set by the constructor ...
 314  314   *
 315  315   *      mutex_enter(&container->c_objects_lock);
 316  316   *      list_insert_tail(&container->c_objects, object);
 317  317   *      membar_producer();
 318  318   *      object->o_container = container;
 319  319   *      mutex_exit(&container->c_objects_lock);
 320  320   *
 321  321   * Note that everything else must be valid before setting o_container makes the
 322  322   * object fair game for the move callback. The membar_producer() call ensures
 323  323   * that all the object's state is written to memory before setting the pointer
 324  324   * that transitions the object from state #3 or #7 (allocated, constructed, not
 325  325   * yet in use) to state #4 (in use, valid). That's important because the move
 326  326   * function has to check the validity of the pointer before it can safely
 327  327   * acquire the lock protecting the collection where it expects to find known
 328  328   * objects.
 329  329   *
 330  330   * This method of distinguishing known objects observes the usual symmetry:
 331  331   * invalidating the designated pointer is the first thing the client does before
 332  332   * freeing the object, and setting the designated pointer is the last thing the
 333  333   * client does after allocating the object. Of course, the client is not
 334  334   * required to use this method. Fundamentally, how the client recognizes known
 335  335   * objects is completely up to the client, but this method is recommended as an
 336  336   * efficient and safe way to take advantage of the guarantees made by kmem. If
 337  337   * the entire object is arbitrary data without any markable bits from a suitable
 338  338   * pointer member, then the client must find some other method, such as
 339  339   * searching a hash table of known objects.
 340  340   *
 341  341   * 2.5 Preventing Objects From Moving
 342  342   *
 343  343   * Besides a way to distinguish known objects, the other thing that the client
 344  344   * needs is a strategy to ensure that an object will not move while the client
 345  345   * is actively using it. The details of satisfying this requirement tend to be
 346  346   * highly cache-specific. It might seem that the same rules that let a client
 347  347   * remove an object safely should also decide when an object can be moved
 348  348   * safely. However, any object state that makes a removal attempt invalid is
 349  349   * likely to be long-lasting for objects that the client does not expect to
 350  350   * remove. kmem knows nothing about the object state and is equally likely (from
 351  351   * the client's point of view) to request a move for any object in the cache,
 352  352   * whether prepared for removal or not. Even a low percentage of objects stuck
 353  353   * in place by unremovability will defeat the consolidator if the stuck objects
 354  354   * are the same long-lived allocations likely to hold slabs hostage.
 355  355   * Fundamentally, the consolidator is not aimed at common cases. Severe external
 356  356   * fragmentation is a worst case scenario manifested as sparsely allocated
 357  357   * slabs, by definition a low percentage of the cache's objects. When deciding
 358  358   * what makes an object movable, keep in mind the goal of the consolidator: to
 359  359   * bring worst-case external fragmentation within the limits guaranteed for
 360  360   * internal fragmentation. Removability is a poor criterion if it is likely to
 361  361   * exclude more than an insignificant percentage of objects for long periods of
 362  362   * time.
 363  363   *
 364  364   * A tricky general solution exists, and it has the advantage of letting you
 365  365   * move any object at almost any moment, practically eliminating the likelihood
 366  366   * that an object can hold a slab hostage. However, if there is a cache-specific
 367  367   * way to ensure that an object is not actively in use in the vast majority of
 368  368   * cases, a simpler solution that leverages this cache-specific knowledge is
 369  369   * preferred.
 370  370   *
 371  371   * 2.5.1 Cache-Specific Solution
 372  372   *
 373  373   * As an example of a cache-specific solution, the ZFS znode cache takes
 374  374   * advantage of the fact that the vast majority of znodes are only being
 375  375   * referenced from the DNLC. (A typical case might be a few hundred in active
 376  376   * use and a hundred thousand in the DNLC.) In the move callback, after the ZFS
 377  377   * client has established that it recognizes the znode and can access its fields
 378  378   * safely (using the method described earlier), it then tests whether the znode
 379  379   * is referenced by anything other than the DNLC. If so, it assumes that the
 380  380   * znode may be in active use and is unsafe to move, so it drops its locks and
 381  381   * returns KMEM_CBRC_LATER. The advantage of this strategy is that everywhere
 382  382   * else znodes are used, no change is needed to protect against the possibility
 383  383   * of the znode moving. The disadvantage is that it remains possible for an
 384  384   * application to hold a znode slab hostage with an open file descriptor.
 385  385   * However, this case ought to be rare and the consolidator has a way to deal
 386  386   * with it: If the client responds KMEM_CBRC_LATER repeatedly for the same
 387  387   * object, kmem eventually stops believing it and treats the slab as if the
 388  388   * client had responded KMEM_CBRC_NO. Having marked the hostage slab, kmem can
 389  389   * then focus on getting it off of the partial slab list by allocating rather
 390  390   * than freeing all of its objects. (Either way of getting a slab off the
 391  391   * free list reduces fragmentation.)
 392  392   *
 393  393   * 2.5.2 General Solution
 394  394   *
 395  395   * The general solution, on the other hand, requires an explicit hold everywhere
 396  396   * the object is used to prevent it from moving. To keep the client locking
 397  397   * strategy as uncomplicated as possible, kmem guarantees the simplifying
 398  398   * assumption that move callbacks are sequential, even across multiple caches.
 399  399   * Internally, a global queue processed by a single thread supports all caches
 400  400   * implementing the callback function. No matter how many caches supply a move
 401  401   * function, the consolidator never moves more than one object at a time, so the
 402  402   * client does not have to worry about tricky lock ordering involving several
 403  403   * related objects from different kmem caches.
 404  404   *
 405  405   * The general solution implements the explicit hold as a read-write lock, which
 406  406   * allows multiple readers to access an object from the cache simultaneously
 407  407   * while a single writer is excluded from moving it. A single rwlock for the
 408  408   * entire cache would lock out all threads from using any of the cache's objects
 409  409   * even though only a single object is being moved, so to reduce contention,
 410  410   * the client can fan out the single rwlock into an array of rwlocks hashed by
 411  411   * the object address, making it probable that moving one object will not
 412  412   * prevent other threads from using a different object. The rwlock cannot be a
 413  413   * member of the object itself, because the possibility of the object moving
 414  414   * makes it unsafe to access any of the object's fields until the lock is
 415  415   * acquired.
 416  416   *
 417  417   * Assuming a small, fixed number of locks, it's possible that multiple objects
 418  418   * will hash to the same lock. A thread that needs to use multiple objects in
 419  419   * the same function may acquire the same lock multiple times. Since rwlocks are
 420  420   * reentrant for readers, and since there is never more than a single writer at
 421  421   * a time (assuming that the client acquires the lock as a writer only when
 422  422   * moving an object inside the callback), there would seem to be no problem.
 423  423   * However, a client locking multiple objects in the same function must handle
 424  424   * one case of potential deadlock: Assume that thread A needs to prevent both
 425  425   * object 1 and object 2 from moving, and thread B, the callback, meanwhile
 426  426   * tries to move object 3. It's possible, if objects 1, 2, and 3 all hash to the
 427  427   * same lock, that thread A will acquire the lock for object 1 as a reader
 428  428   * before thread B sets the lock's write-wanted bit, preventing thread A from
 429  429   * reacquiring the lock for object 2 as a reader. Unable to make forward
 430  430   * progress, thread A will never release the lock for object 1, resulting in
 431  431   * deadlock.
 432  432   *
 433  433   * There are two ways of avoiding the deadlock just described. The first is to
 434  434   * use rw_tryenter() rather than rw_enter() in the callback function when
 435  435   * attempting to acquire the lock as a writer. If tryenter discovers that the
 436  436   * same object (or another object hashed to the same lock) is already in use, it
 437  437   * aborts the callback and returns KMEM_CBRC_LATER. The second way is to use
 438  438   * rprwlock_t (declared in common/fs/zfs/sys/rprwlock.h) instead of rwlock_t,
 439  439   * since it allows a thread to acquire the lock as a reader in spite of a
 440  440   * waiting writer. This second approach insists on moving the object now, no
 441  441   * matter how many readers the move function must wait for in order to do so,
 442  442   * and could delay the completion of the callback indefinitely (blocking
 443  443   * callbacks to other clients). In practice, a less insistent callback using
 444  444   * rw_tryenter() returns KMEM_CBRC_LATER infrequently enough that there seems
 445  445   * little reason to use anything else.
 446  446   *
 447  447   * Avoiding deadlock is not the only problem that an implementation using an
 448  448   * explicit hold needs to solve. Locking the object in the first place (to
 449  449   * prevent it from moving) remains a problem, since the object could move
 450  450   * between the time you obtain a pointer to the object and the time you acquire
 451  451   * the rwlock hashed to that pointer value. Therefore the client needs to
 452  452   * recheck the value of the pointer after acquiring the lock, drop the lock if
 453  453   * the value has changed, and try again. This requires a level of indirection:
 454  454   * something that points to the object rather than the object itself, that the
 455  455   * client can access safely while attempting to acquire the lock. (The object
 456  456   * itself cannot be referenced safely because it can move at any time.)
 457  457   * The following lock-acquisition function takes whatever is safe to reference
 458  458   * (arg), follows its pointer to the object (using function f), and tries as
 459  459   * often as necessary to acquire the hashed lock and verify that the object
 460  460   * still has not moved:
 461  461   *
 462  462   *      object_t *
 463  463   *      object_hold(object_f f, void *arg)
 464  464   *      {
 465  465   *              object_t *op;
 466  466   *
 467  467   *              op = f(arg);
 468  468   *              if (op == NULL) {
 469  469   *                      return (NULL);
 470  470   *              }
 471  471   *
 472  472   *              rw_enter(OBJECT_RWLOCK(op), RW_READER);
 473  473   *              while (op != f(arg)) {
 474  474   *                      rw_exit(OBJECT_RWLOCK(op));
 475  475   *                      op = f(arg);
 476  476   *                      if (op == NULL) {
 477  477   *                              break;
 478  478   *                      }
 479  479   *                      rw_enter(OBJECT_RWLOCK(op), RW_READER);
 480  480   *              }
 481  481   *
 482  482   *              return (op);
 483  483   *      }
 484  484   *
 485  485   * The OBJECT_RWLOCK macro hashes the object address to obtain the rwlock. The
 486  486   * lock reacquisition loop, while necessary, almost never executes. The function
 487  487   * pointer f (used to obtain the object pointer from arg) has the following type
 488  488   * definition:
 489  489   *
 490  490   *      typedef object_t *(*object_f)(void *arg);
 491  491   *
 492  492   * An object_f implementation is likely to be as simple as accessing a structure
 493  493   * member:
 494  494   *
 495  495   *      object_t *
 496  496   *      s_object(void *arg)
 497  497   *      {
 498  498   *              something_t *sp = arg;
 499  499   *              return (sp->s_object);
 500  500   *      }
 501  501   *
 502  502   * The flexibility of a function pointer allows the path to the object to be
 503  503   * arbitrarily complex and also supports the notion that depending on where you
 504  504   * are using the object, you may need to get it from someplace different.
 505  505   *
 506  506   * The function that releases the explicit hold is simpler because it does not
 507  507   * have to worry about the object moving:
 508  508   *
 509  509   *      void
 510  510   *      object_rele(object_t *op)
 511  511   *      {
 512  512   *              rw_exit(OBJECT_RWLOCK(op));
 513  513   *      }
 514  514   *
 515  515   * The caller is spared these details so that obtaining and releasing an
 516  516   * explicit hold feels like a simple mutex_enter()/mutex_exit() pair. The caller
 517  517   * of object_hold() only needs to know that the returned object pointer is valid
 518  518   * if not NULL and that the object will not move until released.
 519  519   *
 520  520   * Although object_hold() prevents an object from moving, it does not prevent it
 521  521   * from being freed. The caller must take measures before calling object_hold()
 522  522   * (afterwards is too late) to ensure that the held object cannot be freed. The
 523  523   * caller must do so without accessing the unsafe object reference, so any lock
 524  524   * or reference count used to ensure the continued existence of the object must
 525  525   * live outside the object itself.
 526  526   *
 527  527   * Obtaining a new object is a special case where an explicit hold is impossible
 528  528   * for the caller. Any function that returns a newly allocated object (either as
 529  529   * a return value, or as an in-out paramter) must return it already held; after
 530  530   * the caller gets it is too late, since the object cannot be safely accessed
 531  531   * without the level of indirection described earlier. The following
 532  532   * object_alloc() example uses the same code shown earlier to transition a new
 533  533   * object into the state of being recognized (by the client) as a known object.
 534  534   * The function must acquire the hold (rw_enter) before that state transition
 535  535   * makes the object movable:
 536  536   *
 537  537   *      static object_t *
 538  538   *      object_alloc(container_t *container)
 539  539   *      {
 540  540   *              object_t *object = kmem_cache_alloc(object_cache, 0);
 541  541   *              ... set any initial state not set by the constructor ...
 542  542   *              rw_enter(OBJECT_RWLOCK(object), RW_READER);
 543  543   *              mutex_enter(&container->c_objects_lock);
 544  544   *              list_insert_tail(&container->c_objects, object);
 545  545   *              membar_producer();
 546  546   *              object->o_container = container;
 547  547   *              mutex_exit(&container->c_objects_lock);
 548  548   *              return (object);
 549  549   *      }
 550  550   *
 551  551   * Functions that implicitly acquire an object hold (any function that calls
 552  552   * object_alloc() to supply an object for the caller) need to be carefully noted
 553  553   * so that the matching object_rele() is not neglected. Otherwise, leaked holds
 554  554   * prevent all objects hashed to the affected rwlocks from ever being moved.
 555  555   *
 556  556   * The pointer to a held object can be hashed to the holding rwlock even after
 557  557   * the object has been freed. Although it is possible to release the hold
 558  558   * after freeing the object, you may decide to release the hold implicitly in
 559  559   * whatever function frees the object, so as to release the hold as soon as
 560  560   * possible, and for the sake of symmetry with the function that implicitly
 561  561   * acquires the hold when it allocates the object. Here, object_free() releases
 562  562   * the hold acquired by object_alloc(). Its implicit object_rele() forms a
 563  563   * matching pair with object_hold():
 564  564   *
 565  565   *      void
 566  566   *      object_free(object_t *object)
 567  567   *      {
 568  568   *              container_t *container;
 569  569   *
 570  570   *              ASSERT(object_held(object));
 571  571   *              container = object->o_container;
 572  572   *              mutex_enter(&container->c_objects_lock);
 573  573   *              object->o_container =
 574  574   *                  (void *)((uintptr_t)object->o_container | 0x1);
 575  575   *              list_remove(&container->c_objects, object);
 576  576   *              mutex_exit(&container->c_objects_lock);
 577  577   *              object_rele(object);
 578  578   *              kmem_cache_free(object_cache, object);
 579  579   *      }
 580  580   *
 581  581   * Note that object_free() cannot safely accept an object pointer as an argument
 582  582   * unless the object is already held. Any function that calls object_free()
 583  583   * needs to be carefully noted since it similarly forms a matching pair with
 584  584   * object_hold().
 585  585   *
 586  586   * To complete the picture, the following callback function implements the
 587  587   * general solution by moving objects only if they are currently unheld:
 588  588   *
 589  589   *      static kmem_cbrc_t
 590  590   *      object_move(void *buf, void *newbuf, size_t size, void *arg)
 591  591   *      {
 592  592   *              object_t *op = buf, *np = newbuf;
 593  593   *              container_t *container;
 594  594   *
 595  595   *              container = op->o_container;
 596  596   *              if ((uintptr_t)container & 0x3) {
 597  597   *                      return (KMEM_CBRC_DONT_KNOW);
 598  598   *              }
 599  599   *
 600  600   *              // Ensure that the container structure does not go away.
 601  601   *              if (container_hold(container) == 0) {
 602  602   *                      return (KMEM_CBRC_DONT_KNOW);
 603  603   *              }
 604  604   *
 605  605   *              mutex_enter(&container->c_objects_lock);
 606  606   *              if (container != op->o_container) {
 607  607   *                      mutex_exit(&container->c_objects_lock);
 608  608   *                      container_rele(container);
 609  609   *                      return (KMEM_CBRC_DONT_KNOW);
 610  610   *              }
 611  611   *
 612  612   *              if (rw_tryenter(OBJECT_RWLOCK(op), RW_WRITER) == 0) {
 613  613   *                      mutex_exit(&container->c_objects_lock);
 614  614   *                      container_rele(container);
 615  615   *                      return (KMEM_CBRC_LATER);
 616  616   *              }
 617  617   *
 618  618   *              object_move_impl(op, np); // critical section
 619  619   *              rw_exit(OBJECT_RWLOCK(op));
 620  620   *
 621  621   *              op->o_container = (void *)((uintptr_t)op->o_container | 0x1);
 622  622   *              list_link_replace(&op->o_link_node, &np->o_link_node);
 623  623   *              mutex_exit(&container->c_objects_lock);
 624  624   *              container_rele(container);
 625  625   *              return (KMEM_CBRC_YES);
 626  626   *      }
 627  627   *
 628  628   * Note that object_move() must invalidate the designated o_container pointer of
 629  629   * the old object in the same way that object_free() does, since kmem will free
 630  630   * the object in response to the KMEM_CBRC_YES return value.
 631  631   *
 632  632   * The lock order in object_move() differs from object_alloc(), which locks
 633  633   * OBJECT_RWLOCK first and &container->c_objects_lock second, but as long as the
 634  634   * callback uses rw_tryenter() (preventing the deadlock described earlier), it's
 635  635   * not a problem. Holding the lock on the object list in the example above
 636  636   * through the entire callback not only prevents the object from going away, it
 637  637   * also allows you to lock the list elsewhere and know that none of its elements
 638  638   * will move during iteration.
 639  639   *
 640  640   * Adding an explicit hold everywhere an object from the cache is used is tricky
 641  641   * and involves much more change to client code than a cache-specific solution
 642  642   * that leverages existing state to decide whether or not an object is
 643  643   * movable. However, this approach has the advantage that no object remains
 644  644   * immovable for any significant length of time, making it extremely unlikely
 645  645   * that long-lived allocations can continue holding slabs hostage; and it works
 646  646   * for any cache.
 647  647   *
 648  648   * 3. Consolidator Implementation
 649  649   *
 650  650   * Once the client supplies a move function that a) recognizes known objects and
 651  651   * b) avoids moving objects that are actively in use, the remaining work is up
 652  652   * to the consolidator to decide which objects to move and when to issue
 653  653   * callbacks.
 654  654   *
 655  655   * The consolidator relies on the fact that a cache's slabs are ordered by
 656  656   * usage. Each slab has a fixed number of objects. Depending on the slab's
 657  657   * "color" (the offset of the first object from the beginning of the slab;
 658  658   * offsets are staggered to mitigate false sharing of cache lines) it is either
 659  659   * the maximum number of objects per slab determined at cache creation time or
 660  660   * else the number closest to the maximum that fits within the space remaining
 661  661   * after the initial offset. A completely allocated slab may contribute some
 662  662   * internal fragmentation (per-slab overhead) but no external fragmentation, so
 663  663   * it is of no interest to the consolidator. At the other extreme, slabs whose
 664  664   * objects have all been freed to the slab are released to the virtual memory
 665  665   * (VM) subsystem (objects freed to magazines are still allocated as far as the
 666  666   * slab is concerned). External fragmentation exists when there are slabs
 667  667   * somewhere between these extremes. A partial slab has at least one but not all
 668  668   * of its objects allocated. The more partial slabs, and the fewer allocated
 669  669   * objects on each of them, the higher the fragmentation. Hence the
 670  670   * consolidator's overall strategy is to reduce the number of partial slabs by
 671  671   * moving allocated objects from the least allocated slabs to the most allocated
 672  672   * slabs.
 673  673   *
 674  674   * Partial slabs are kept in an AVL tree ordered by usage. Completely allocated
 675  675   * slabs are kept separately in an unordered list. Since the majority of slabs
 676  676   * tend to be completely allocated (a typical unfragmented cache may have
 677  677   * thousands of complete slabs and only a single partial slab), separating
 678  678   * complete slabs improves the efficiency of partial slab ordering, since the
 679  679   * complete slabs do not affect the depth or balance of the AVL tree. This
 680  680   * ordered sequence of partial slabs acts as a "free list" supplying objects for
 681  681   * allocation requests.
 682  682   *
 683  683   * Objects are always allocated from the first partial slab in the free list,
 684  684   * where the allocation is most likely to eliminate a partial slab (by
 685  685   * completely allocating it). Conversely, when a single object from a completely
 686  686   * allocated slab is freed to the slab, that slab is added to the front of the
 687  687   * free list. Since most free list activity involves highly allocated slabs
 688  688   * coming and going at the front of the list, slabs tend naturally toward the
 689  689   * ideal order: highly allocated at the front, sparsely allocated at the back.
 690  690   * Slabs with few allocated objects are likely to become completely free if they
 691  691   * keep a safe distance away from the front of the free list. Slab misorders
 692  692   * interfere with the natural tendency of slabs to become completely free or
 693  693   * completely allocated. For example, a slab with a single allocated object
 694  694   * needs only a single free to escape the cache; its natural desire is
 695  695   * frustrated when it finds itself at the front of the list where a second
 696  696   * allocation happens just before the free could have released it. Another slab
 697  697   * with all but one object allocated might have supplied the buffer instead, so
 698  698   * that both (as opposed to neither) of the slabs would have been taken off the
 699  699   * free list.
 700  700   *
 701  701   * Although slabs tend naturally toward the ideal order, misorders allowed by a
 702  702   * simple list implementation defeat the consolidator's strategy of merging
 703  703   * least- and most-allocated slabs. Without an AVL tree to guarantee order, kmem
 704  704   * needs another way to fix misorders to optimize its callback strategy. One
 705  705   * approach is to periodically scan a limited number of slabs, advancing a
 706  706   * marker to hold the current scan position, and to move extreme misorders to
 707  707   * the front or back of the free list and to the front or back of the current
 708  708   * scan range. By making consecutive scan ranges overlap by one slab, the least
 709  709   * allocated slab in the current range can be carried along from the end of one
 710  710   * scan to the start of the next.
 711  711   *
 712  712   * Maintaining partial slabs in an AVL tree relieves kmem of this additional
 713  713   * task, however. Since most of the cache's activity is in the magazine layer,
 714  714   * and allocations from the slab layer represent only a startup cost, the
 715  715   * overhead of maintaining a balanced tree is not a significant concern compared
 716  716   * to the opportunity of reducing complexity by eliminating the partial slab
 717  717   * scanner just described. The overhead of an AVL tree is minimized by
 718  718   * maintaining only partial slabs in the tree and keeping completely allocated
 719  719   * slabs separately in a list. To avoid increasing the size of the slab
 720  720   * structure the AVL linkage pointers are reused for the slab's list linkage,
 721  721   * since the slab will always be either partial or complete, never stored both
 722  722   * ways at the same time. To further minimize the overhead of the AVL tree the
 723  723   * compare function that orders partial slabs by usage divides the range of
 724  724   * allocated object counts into bins such that counts within the same bin are
 725  725   * considered equal. Binning partial slabs makes it less likely that allocating
 726  726   * or freeing a single object will change the slab's order, requiring a tree
 727  727   * reinsertion (an avl_remove() followed by an avl_add(), both potentially
 728  728   * requiring some rebalancing of the tree). Allocation counts closest to
 729  729   * completely free and completely allocated are left unbinned (finely sorted) to
 730  730   * better support the consolidator's strategy of merging slabs at either
 731  731   * extreme.
 732  732   *
 733  733   * 3.1 Assessing Fragmentation and Selecting Candidate Slabs
 734  734   *
 735  735   * The consolidator piggybacks on the kmem maintenance thread and is called on
 736  736   * the same interval as kmem_cache_update(), once per cache every fifteen
 737  737   * seconds. kmem maintains a running count of unallocated objects in the slab
 738  738   * layer (cache_bufslab). The consolidator checks whether that number exceeds
 739  739   * 12.5% (1/8) of the total objects in the cache (cache_buftotal), and whether
 740  740   * there is a significant number of slabs in the cache (arbitrarily a minimum
 741  741   * 101 total slabs). Unused objects that have fallen out of the magazine layer's
 742  742   * working set are included in the assessment, and magazines in the depot are
 743  743   * reaped if those objects would lift cache_bufslab above the fragmentation
 744  744   * threshold. Once the consolidator decides that a cache is fragmented, it looks
 745  745   * for a candidate slab to reclaim, starting at the end of the partial slab free
 746  746   * list and scanning backwards. At first the consolidator is choosy: only a slab
 747  747   * with fewer than 12.5% (1/8) of its objects allocated qualifies (or else a
 748  748   * single allocated object, regardless of percentage). If there is difficulty
 749  749   * finding a candidate slab, kmem raises the allocation threshold incrementally,
 750  750   * up to a maximum 87.5% (7/8), so that eventually the consolidator will reduce
 751  751   * external fragmentation (unused objects on the free list) below 12.5% (1/8),
 752  752   * even in the worst case of every slab in the cache being almost 7/8 allocated.
 753  753   * The threshold can also be lowered incrementally when candidate slabs are easy
 754  754   * to find, and the threshold is reset to the minimum 1/8 as soon as the cache
 755  755   * is no longer fragmented.
 756  756   *
 757  757   * 3.2 Generating Callbacks
 758  758   *
 759  759   * Once an eligible slab is chosen, a callback is generated for every allocated
 760  760   * object on the slab, in the hope that the client will move everything off the
 761  761   * slab and make it reclaimable. Objects selected as move destinations are
 762  762   * chosen from slabs at the front of the free list. Assuming slabs in the ideal
 763  763   * order (most allocated at the front, least allocated at the back) and a
 764  764   * cooperative client, the consolidator will succeed in removing slabs from both
 765  765   * ends of the free list, completely allocating on the one hand and completely
 766  766   * freeing on the other. Objects selected as move destinations are allocated in
 767  767   * the kmem maintenance thread where move requests are enqueued. A separate
 768  768   * callback thread removes pending callbacks from the queue and calls the
 769  769   * client. The separate thread ensures that client code (the move function) does
 770  770   * not interfere with internal kmem maintenance tasks. A map of pending
 771  771   * callbacks keyed by object address (the object to be moved) is checked to
 772  772   * ensure that duplicate callbacks are not generated for the same object.
 773  773   * Allocating the move destination (the object to move to) prevents subsequent
 774  774   * callbacks from selecting the same destination as an earlier pending callback.
 775  775   *
 776  776   * Move requests can also be generated by kmem_cache_reap() when the system is
 777  777   * desperate for memory and by kmem_cache_move_notify(), called by the client to
 778  778   * notify kmem that a move refused earlier with KMEM_CBRC_LATER is now possible.
 779  779   * The map of pending callbacks is protected by the same lock that protects the
 780  780   * slab layer.
 781  781   *
 782  782   * When the system is desperate for memory, kmem does not bother to determine
 783  783   * whether or not the cache exceeds the fragmentation threshold, but tries to
 784  784   * consolidate as many slabs as possible. Normally, the consolidator chews
 785  785   * slowly, one sparsely allocated slab at a time during each maintenance
 786  786   * interval that the cache is fragmented. When desperate, the consolidator
 787  787   * starts at the last partial slab and enqueues callbacks for every allocated
 788  788   * object on every partial slab, working backwards until it reaches the first
 789  789   * partial slab. The first partial slab, meanwhile, advances in pace with the
 790  790   * consolidator as allocations to supply move destinations for the enqueued
 791  791   * callbacks use up the highly allocated slabs at the front of the free list.
 792  792   * Ideally, the overgrown free list collapses like an accordion, starting at
 793  793   * both ends and ending at the center with a single partial slab.
 794  794   *
 795  795   * 3.3 Client Responses
 796  796   *
 797  797   * When the client returns KMEM_CBRC_NO in response to the move callback, kmem
 798  798   * marks the slab that supplied the stuck object non-reclaimable and moves it to
 799  799   * front of the free list. The slab remains marked as long as it remains on the
 800  800   * free list, and it appears more allocated to the partial slab compare function
 801  801   * than any unmarked slab, no matter how many of its objects are allocated.
 802  802   * Since even one immovable object ties up the entire slab, the goal is to
 803  803   * completely allocate any slab that cannot be completely freed. kmem does not
 804  804   * bother generating callbacks to move objects from a marked slab unless the
 805  805   * system is desperate.
 806  806   *
 807  807   * When the client responds KMEM_CBRC_LATER, kmem increments a count for the
 808  808   * slab. If the client responds LATER too many times, kmem disbelieves and
 809  809   * treats the response as a NO. The count is cleared when the slab is taken off
 810  810   * the partial slab list or when the client moves one of the slab's objects.
 811  811   *
 812  812   * 4. Observability
 813  813   *
 814  814   * A kmem cache's external fragmentation is best observed with 'mdb -k' using
 815  815   * the ::kmem_slabs dcmd. For a complete description of the command, enter
 816  816   * '::help kmem_slabs' at the mdb prompt.
 817  817   */
 818  818  
 819  819  #include <sys/kmem_impl.h>
 820  820  #include <sys/vmem_impl.h>
 821  821  #include <sys/param.h>
 822  822  #include <sys/sysmacros.h>
 823  823  #include <sys/vm.h>
 824  824  #include <sys/proc.h>
 825  825  #include <sys/tuneable.h>
 826  826  #include <sys/systm.h>
 827  827  #include <sys/cmn_err.h>
 828  828  #include <sys/debug.h>
 829  829  #include <sys/sdt.h>
 830  830  #include <sys/mutex.h>
 831  831  #include <sys/bitmap.h>
 832  832  #include <sys/atomic.h>
 833  833  #include <sys/kobj.h>
 834  834  #include <sys/disp.h>
 835  835  #include <vm/seg_kmem.h>
 836  836  #include <sys/log.h>
 837  837  #include <sys/callb.h>
 838  838  #include <sys/taskq.h>
 839  839  #include <sys/modctl.h>
 840  840  #include <sys/reboot.h>
 841  841  #include <sys/id32.h>
 842  842  #include <sys/zone.h>
 843  843  #include <sys/netstack.h>
 844  844  #ifdef  DEBUG
 845  845  #include <sys/random.h>
 846  846  #endif
 847  847  
 848  848  extern void streams_msg_init(void);
 849  849  extern int segkp_fromheap;
 850  850  extern void segkp_cache_free(void);
 851  851  extern int callout_init_done;
 852  852  
 853  853  struct kmem_cache_kstat {
 854  854          kstat_named_t   kmc_buf_size;
 855  855          kstat_named_t   kmc_align;
 856  856          kstat_named_t   kmc_chunk_size;
 857  857          kstat_named_t   kmc_slab_size;
 858  858          kstat_named_t   kmc_alloc;
 859  859          kstat_named_t   kmc_alloc_fail;
 860  860          kstat_named_t   kmc_free;
 861  861          kstat_named_t   kmc_depot_alloc;
 862  862          kstat_named_t   kmc_depot_free;
 863  863          kstat_named_t   kmc_depot_contention;
 864  864          kstat_named_t   kmc_slab_alloc;
 865  865          kstat_named_t   kmc_slab_free;
 866  866          kstat_named_t   kmc_buf_constructed;
 867  867          kstat_named_t   kmc_buf_avail;
 868  868          kstat_named_t   kmc_buf_inuse;
 869  869          kstat_named_t   kmc_buf_total;
 870  870          kstat_named_t   kmc_buf_max;
 871  871          kstat_named_t   kmc_slab_create;
 872  872          kstat_named_t   kmc_slab_destroy;
 873  873          kstat_named_t   kmc_vmem_source;
 874  874          kstat_named_t   kmc_hash_size;
 875  875          kstat_named_t   kmc_hash_lookup_depth;
 876  876          kstat_named_t   kmc_hash_rescale;
 877  877          kstat_named_t   kmc_full_magazines;
 878  878          kstat_named_t   kmc_empty_magazines;
 879  879          kstat_named_t   kmc_magazine_size;
 880  880          kstat_named_t   kmc_reap; /* number of kmem_cache_reap() calls */
 881  881          kstat_named_t   kmc_defrag; /* attempts to defrag all partial slabs */
 882  882          kstat_named_t   kmc_scan; /* attempts to defrag one partial slab */
 883  883          kstat_named_t   kmc_move_callbacks; /* sum of yes, no, later, dn, dk */
 884  884          kstat_named_t   kmc_move_yes;
 885  885          kstat_named_t   kmc_move_no;
 886  886          kstat_named_t   kmc_move_later;
 887  887          kstat_named_t   kmc_move_dont_need;
 888  888          kstat_named_t   kmc_move_dont_know; /* obj unrecognized by client ... */
 889  889          kstat_named_t   kmc_move_hunt_found; /* ... but found in mag layer */
 890  890          kstat_named_t   kmc_move_slabs_freed; /* slabs freed by consolidator */
 891  891          kstat_named_t   kmc_move_reclaimable; /* buffers, if consolidator ran */
 892  892  } kmem_cache_kstat = {
 893  893          { "buf_size",           KSTAT_DATA_UINT64 },
 894  894          { "align",              KSTAT_DATA_UINT64 },
 895  895          { "chunk_size",         KSTAT_DATA_UINT64 },
 896  896          { "slab_size",          KSTAT_DATA_UINT64 },
 897  897          { "alloc",              KSTAT_DATA_UINT64 },
 898  898          { "alloc_fail",         KSTAT_DATA_UINT64 },
 899  899          { "free",               KSTAT_DATA_UINT64 },
 900  900          { "depot_alloc",        KSTAT_DATA_UINT64 },
 901  901          { "depot_free",         KSTAT_DATA_UINT64 },
 902  902          { "depot_contention",   KSTAT_DATA_UINT64 },
 903  903          { "slab_alloc",         KSTAT_DATA_UINT64 },
 904  904          { "slab_free",          KSTAT_DATA_UINT64 },
 905  905          { "buf_constructed",    KSTAT_DATA_UINT64 },
 906  906          { "buf_avail",          KSTAT_DATA_UINT64 },
 907  907          { "buf_inuse",          KSTAT_DATA_UINT64 },
 908  908          { "buf_total",          KSTAT_DATA_UINT64 },
 909  909          { "buf_max",            KSTAT_DATA_UINT64 },
 910  910          { "slab_create",        KSTAT_DATA_UINT64 },
 911  911          { "slab_destroy",       KSTAT_DATA_UINT64 },
 912  912          { "vmem_source",        KSTAT_DATA_UINT64 },
 913  913          { "hash_size",          KSTAT_DATA_UINT64 },
 914  914          { "hash_lookup_depth",  KSTAT_DATA_UINT64 },
 915  915          { "hash_rescale",       KSTAT_DATA_UINT64 },
 916  916          { "full_magazines",     KSTAT_DATA_UINT64 },
 917  917          { "empty_magazines",    KSTAT_DATA_UINT64 },
 918  918          { "magazine_size",      KSTAT_DATA_UINT64 },
 919  919          { "reap",               KSTAT_DATA_UINT64 },
 920  920          { "defrag",             KSTAT_DATA_UINT64 },
 921  921          { "scan",               KSTAT_DATA_UINT64 },
 922  922          { "move_callbacks",     KSTAT_DATA_UINT64 },
 923  923          { "move_yes",           KSTAT_DATA_UINT64 },
 924  924          { "move_no",            KSTAT_DATA_UINT64 },
 925  925          { "move_later",         KSTAT_DATA_UINT64 },
 926  926          { "move_dont_need",     KSTAT_DATA_UINT64 },
 927  927          { "move_dont_know",     KSTAT_DATA_UINT64 },
 928  928          { "move_hunt_found",    KSTAT_DATA_UINT64 },
 929  929          { "move_slabs_freed",   KSTAT_DATA_UINT64 },
 930  930          { "move_reclaimable",   KSTAT_DATA_UINT64 },
 931  931  };
 932  932  
 933  933  static kmutex_t kmem_cache_kstat_lock;
 934  934  
 935  935  /*
 936  936   * The default set of caches to back kmem_alloc().
 937  937   * These sizes should be reevaluated periodically.
 938  938   *
 939  939   * We want allocations that are multiples of the coherency granularity
 940  940   * (64 bytes) to be satisfied from a cache which is a multiple of 64
 941  941   * bytes, so that it will be 64-byte aligned.  For all multiples of 64,
 942  942   * the next kmem_cache_size greater than or equal to it must be a
 943  943   * multiple of 64.
 944  944   *
 945  945   * We split the table into two sections:  size <= 4k and size > 4k.  This
 946  946   * saves a lot of space and cache footprint in our cache tables.
 947  947   */
 948  948  static const int kmem_alloc_sizes[] = {
 949  949          1 * 8,
 950  950          2 * 8,
 951  951          3 * 8,
 952  952          4 * 8,          5 * 8,          6 * 8,          7 * 8,
 953  953          4 * 16,         5 * 16,         6 * 16,         7 * 16,
 954  954          4 * 32,         5 * 32,         6 * 32,         7 * 32,
 955  955          4 * 64,         5 * 64,         6 * 64,         7 * 64,
 956  956          4 * 128,        5 * 128,        6 * 128,        7 * 128,
 957  957          P2ALIGN(8192 / 7, 64),
 958  958          P2ALIGN(8192 / 6, 64),
 959  959          P2ALIGN(8192 / 5, 64),
 960  960          P2ALIGN(8192 / 4, 64),
 961  961          P2ALIGN(8192 / 3, 64),
 962  962          P2ALIGN(8192 / 2, 64),
 963  963  };
 964  964  
 965  965  static const int kmem_big_alloc_sizes[] = {
 966  966          2 * 4096,       3 * 4096,
 967  967          2 * 8192,       3 * 8192,
 968  968          4 * 8192,       5 * 8192,       6 * 8192,       7 * 8192,
 969  969          8 * 8192,       9 * 8192,       10 * 8192,      11 * 8192,
 970  970          12 * 8192,      13 * 8192,      14 * 8192,      15 * 8192,
 971  971          16 * 8192
 972  972  };
 973  973  
 974  974  #define KMEM_MAXBUF             4096
 975  975  #define KMEM_BIG_MAXBUF_32BIT   32768
 976  976  #define KMEM_BIG_MAXBUF         131072
 977  977  
 978  978  #define KMEM_BIG_MULTIPLE       4096    /* big_alloc_sizes must be a multiple */
 979  979  #define KMEM_BIG_SHIFT          12      /* lg(KMEM_BIG_MULTIPLE) */
 980  980  
 981  981  static kmem_cache_t *kmem_alloc_table[KMEM_MAXBUF >> KMEM_ALIGN_SHIFT];
 982  982  static kmem_cache_t *kmem_big_alloc_table[KMEM_BIG_MAXBUF >> KMEM_BIG_SHIFT];
 983  983  
 984  984  #define KMEM_ALLOC_TABLE_MAX    (KMEM_MAXBUF >> KMEM_ALIGN_SHIFT)
 985  985  static size_t kmem_big_alloc_table_max = 0;     /* # of filled elements */
 986  986  
 987  987  static kmem_magtype_t kmem_magtype[] = {
 988  988          { 1,    8,      3200,   65536   },
 989  989          { 3,    16,     256,    32768   },
 990  990          { 7,    32,     64,     16384   },
 991  991          { 15,   64,     0,      8192    },
 992  992          { 31,   64,     0,      4096    },
 993  993          { 47,   64,     0,      2048    },
 994  994          { 63,   64,     0,      1024    },
 995  995          { 95,   64,     0,      512     },
 996  996          { 143,  64,     0,      0       },
 997  997  };
 998  998  
 999  999  static uint32_t kmem_reaping;
1000 1000  static uint32_t kmem_reaping_idspace;
1001 1001  
1002 1002  /*
1003 1003   * kmem tunables
1004 1004   */
1005 1005  clock_t kmem_reap_interval;     /* cache reaping rate [15 * HZ ticks] */
1006 1006  int kmem_depot_contention = 3;  /* max failed tryenters per real interval */
1007 1007  pgcnt_t kmem_reapahead = 0;     /* start reaping N pages before pageout */
1008 1008  int kmem_panic = 1;             /* whether to panic on error */
1009 1009  int kmem_logging = 1;           /* kmem_log_enter() override */
1010 1010  uint32_t kmem_mtbf = 0;         /* mean time between failures [default: off] */
1011 1011  size_t kmem_transaction_log_size; /* transaction log size [2% of memory] */
1012 1012  size_t kmem_content_log_size;   /* content log size [2% of memory] */
1013 1013  size_t kmem_failure_log_size;   /* failure log [4 pages per CPU] */
1014 1014  size_t kmem_slab_log_size;      /* slab create log [4 pages per CPU] */
1015 1015  size_t kmem_zerosized_log_size; /* zero-sized log [4 pages per CPU] */
1016 1016  size_t kmem_content_maxsave = 256; /* KMF_CONTENTS max bytes to log */
1017 1017  size_t kmem_lite_minsize = 0;   /* minimum buffer size for KMF_LITE */
1018 1018  size_t kmem_lite_maxalign = 1024; /* maximum buffer alignment for KMF_LITE */
1019 1019  int kmem_lite_pcs = 4;          /* number of PCs to store in KMF_LITE mode */
1020 1020  size_t kmem_maxverify;          /* maximum bytes to inspect in debug routines */
1021 1021  size_t kmem_minfirewall;        /* hardware-enforced redzone threshold */
1022 1022  
1023 1023  #ifdef DEBUG
1024 1024  int kmem_warn_zerosized = 1;    /* whether to warn on zero-sized KM_SLEEP */
1025 1025  #else
1026 1026  int kmem_warn_zerosized = 0;    /* whether to warn on zero-sized KM_SLEEP */
1027 1027  #endif
1028 1028  
1029 1029  int kmem_panic_zerosized = 0;   /* whether to panic on zero-sized KM_SLEEP */
1030 1030  
1031 1031  #ifdef _LP64
1032 1032  size_t  kmem_max_cached = KMEM_BIG_MAXBUF;      /* maximum kmem_alloc cache */
1033 1033  #else
1034 1034  size_t  kmem_max_cached = KMEM_BIG_MAXBUF_32BIT; /* maximum kmem_alloc cache */
1035 1035  #endif
1036 1036  
1037 1037  #ifdef DEBUG
1038 1038  int kmem_flags = KMF_AUDIT | KMF_DEADBEEF | KMF_REDZONE | KMF_CONTENTS;
1039 1039  #else
1040 1040  int kmem_flags = 0;
1041 1041  #endif
1042 1042  int kmem_ready;
1043 1043  
1044 1044  static kmem_cache_t     *kmem_slab_cache;
1045 1045  static kmem_cache_t     *kmem_bufctl_cache;
1046 1046  static kmem_cache_t     *kmem_bufctl_audit_cache;
1047 1047  
1048 1048  static kmutex_t         kmem_cache_lock;        /* inter-cache linkage only */
1049 1049  static list_t           kmem_caches;
1050 1050  
1051 1051  static taskq_t          *kmem_taskq;
1052 1052  static kmutex_t         kmem_flags_lock;
1053 1053  static vmem_t           *kmem_metadata_arena;
1054 1054  static vmem_t           *kmem_msb_arena;        /* arena for metadata caches */
1055 1055  static vmem_t           *kmem_cache_arena;
1056 1056  static vmem_t           *kmem_hash_arena;
1057 1057  static vmem_t           *kmem_log_arena;
1058 1058  static vmem_t           *kmem_oversize_arena;
1059 1059  static vmem_t           *kmem_va_arena;
1060 1060  static vmem_t           *kmem_default_arena;
1061 1061  static vmem_t           *kmem_firewall_va_arena;
1062 1062  static vmem_t           *kmem_firewall_arena;
1063 1063  
1064 1064  static int              kmem_zerosized;         /* # of zero-sized allocs */
1065 1065  
1066 1066  /*
1067 1067   * kmem slab consolidator thresholds (tunables)
1068 1068   */
1069 1069  size_t kmem_frag_minslabs = 101;        /* minimum total slabs */
1070 1070  size_t kmem_frag_numer = 1;             /* free buffers (numerator) */
1071 1071  size_t kmem_frag_denom = KMEM_VOID_FRACTION; /* buffers (denominator) */
1072 1072  /*
1073 1073   * Maximum number of slabs from which to move buffers during a single
1074 1074   * maintenance interval while the system is not low on memory.
1075 1075   */
1076 1076  size_t kmem_reclaim_max_slabs = 1;
1077 1077  /*
1078 1078   * Number of slabs to scan backwards from the end of the partial slab list
1079 1079   * when searching for buffers to relocate.
1080 1080   */
1081 1081  size_t kmem_reclaim_scan_range = 12;
1082 1082  
1083 1083  /* consolidator knobs */
1084 1084  boolean_t kmem_move_noreap;
1085 1085  boolean_t kmem_move_blocked;
1086 1086  boolean_t kmem_move_fulltilt;
1087 1087  boolean_t kmem_move_any_partial;
1088 1088  
1089 1089  #ifdef  DEBUG
1090 1090  /*
1091 1091   * kmem consolidator debug tunables:
1092 1092   * Ensure code coverage by occasionally running the consolidator even when the
1093 1093   * caches are not fragmented (they may never be). These intervals are mean time
1094 1094   * in cache maintenance intervals (kmem_cache_update).
1095 1095   */
1096 1096  uint32_t kmem_mtb_move = 60;    /* defrag 1 slab (~15min) */
1097 1097  uint32_t kmem_mtb_reap = 1800;  /* defrag all slabs (~7.5hrs) */
1098 1098  #endif  /* DEBUG */
1099 1099  
1100 1100  static kmem_cache_t     *kmem_defrag_cache;
1101 1101  static kmem_cache_t     *kmem_move_cache;
1102 1102  static taskq_t          *kmem_move_taskq;
1103 1103  
1104 1104  static void kmem_cache_scan(kmem_cache_t *);
1105 1105  static void kmem_cache_defrag(kmem_cache_t *);
1106 1106  static void kmem_slab_prefill(kmem_cache_t *, kmem_slab_t *);
1107 1107  
1108 1108  
1109 1109  kmem_log_header_t       *kmem_transaction_log;
1110 1110  kmem_log_header_t       *kmem_content_log;
1111 1111  kmem_log_header_t       *kmem_failure_log;
1112 1112  kmem_log_header_t       *kmem_slab_log;
1113 1113  kmem_log_header_t       *kmem_zerosized_log;
1114 1114  
1115 1115  static int              kmem_lite_count; /* # of PCs in kmem_buftag_lite_t */
1116 1116  
1117 1117  #define KMEM_BUFTAG_LITE_ENTER(bt, count, caller)                       \
1118 1118          if ((count) > 0) {                                              \
1119 1119                  pc_t *_s = ((kmem_buftag_lite_t *)(bt))->bt_history;    \
1120 1120                  pc_t *_e;                                               \
1121 1121                  /* memmove() the old entries down one notch */          \
1122 1122                  for (_e = &_s[(count) - 1]; _e > _s; _e--)              \
1123 1123                          *_e = *(_e - 1);                                \
1124 1124                  *_s = (uintptr_t)(caller);                              \
1125 1125          }
1126 1126  
1127 1127  #define KMERR_MODIFIED  0       /* buffer modified while on freelist */
1128 1128  #define KMERR_REDZONE   1       /* redzone violation (write past end of buf) */
1129 1129  #define KMERR_DUPFREE   2       /* freed a buffer twice */
1130 1130  #define KMERR_BADADDR   3       /* freed a bad (unallocated) address */
1131 1131  #define KMERR_BADBUFTAG 4       /* buftag corrupted */
1132 1132  #define KMERR_BADBUFCTL 5       /* bufctl corrupted */
1133 1133  #define KMERR_BADCACHE  6       /* freed a buffer to the wrong cache */
1134 1134  #define KMERR_BADSIZE   7       /* alloc size != free size */
1135 1135  #define KMERR_BADBASE   8       /* buffer base address wrong */
1136 1136  
1137 1137  struct {
1138 1138          hrtime_t        kmp_timestamp;  /* timestamp of panic */
1139 1139          int             kmp_error;      /* type of kmem error */
1140 1140          void            *kmp_buffer;    /* buffer that induced panic */
1141 1141          void            *kmp_realbuf;   /* real start address for buffer */
1142 1142          kmem_cache_t    *kmp_cache;     /* buffer's cache according to client */
1143 1143          kmem_cache_t    *kmp_realcache; /* actual cache containing buffer */
1144 1144          kmem_slab_t     *kmp_slab;      /* slab accoring to kmem_findslab() */
1145 1145          kmem_bufctl_t   *kmp_bufctl;    /* bufctl */
1146 1146  } kmem_panic_info;
1147 1147  
1148 1148  
1149 1149  static void
1150 1150  copy_pattern(uint64_t pattern, void *buf_arg, size_t size)
1151 1151  {
1152 1152          uint64_t *bufend = (uint64_t *)((char *)buf_arg + size);
1153 1153          uint64_t *buf = buf_arg;
1154 1154  
1155 1155          while (buf < bufend)
1156 1156                  *buf++ = pattern;
1157 1157  }
1158 1158  
1159 1159  static void *
1160 1160  verify_pattern(uint64_t pattern, void *buf_arg, size_t size)
1161 1161  {
1162 1162          uint64_t *bufend = (uint64_t *)((char *)buf_arg + size);
1163 1163          uint64_t *buf;
1164 1164  
1165 1165          for (buf = buf_arg; buf < bufend; buf++)
1166 1166                  if (*buf != pattern)
1167 1167                          return (buf);
1168 1168          return (NULL);
1169 1169  }
1170 1170  
1171 1171  static void *
1172 1172  verify_and_copy_pattern(uint64_t old, uint64_t new, void *buf_arg, size_t size)
1173 1173  {
1174 1174          uint64_t *bufend = (uint64_t *)((char *)buf_arg + size);
1175 1175          uint64_t *buf;
1176 1176  
1177 1177          for (buf = buf_arg; buf < bufend; buf++) {
1178 1178                  if (*buf != old) {
1179 1179                          copy_pattern(old, buf_arg,
1180 1180                              (char *)buf - (char *)buf_arg);
1181 1181                          return (buf);
1182 1182                  }
1183 1183                  *buf = new;
1184 1184          }
1185 1185  
1186 1186          return (NULL);
1187 1187  }
1188 1188  
1189 1189  static void
1190 1190  kmem_cache_applyall(void (*func)(kmem_cache_t *), taskq_t *tq, int tqflag)
1191 1191  {
1192 1192          kmem_cache_t *cp;
1193 1193  
1194 1194          mutex_enter(&kmem_cache_lock);
1195 1195          for (cp = list_head(&kmem_caches); cp != NULL;
1196 1196              cp = list_next(&kmem_caches, cp))
1197 1197                  if (tq != NULL)
1198 1198                          (void) taskq_dispatch(tq, (task_func_t *)func, cp,
1199 1199                              tqflag);
1200 1200                  else
1201 1201                          func(cp);
1202 1202          mutex_exit(&kmem_cache_lock);
1203 1203  }
1204 1204  
1205 1205  static void
1206 1206  kmem_cache_applyall_id(void (*func)(kmem_cache_t *), taskq_t *tq, int tqflag)
1207 1207  {
1208 1208          kmem_cache_t *cp;
1209 1209  
1210 1210          mutex_enter(&kmem_cache_lock);
1211 1211          for (cp = list_head(&kmem_caches); cp != NULL;
1212 1212              cp = list_next(&kmem_caches, cp)) {
1213 1213                  if (!(cp->cache_cflags & KMC_IDENTIFIER))
1214 1214                          continue;
1215 1215                  if (tq != NULL)
1216 1216                          (void) taskq_dispatch(tq, (task_func_t *)func, cp,
1217 1217                              tqflag);
1218 1218                  else
1219 1219                          func(cp);
1220 1220          }
1221 1221          mutex_exit(&kmem_cache_lock);
1222 1222  }
1223 1223  
1224 1224  /*
1225 1225   * Debugging support.  Given a buffer address, find its slab.
1226 1226   */
1227 1227  static kmem_slab_t *
1228 1228  kmem_findslab(kmem_cache_t *cp, void *buf)
1229 1229  {
1230 1230          kmem_slab_t *sp;
1231 1231  
1232 1232          mutex_enter(&cp->cache_lock);
1233 1233          for (sp = list_head(&cp->cache_complete_slabs); sp != NULL;
1234 1234              sp = list_next(&cp->cache_complete_slabs, sp)) {
1235 1235                  if (KMEM_SLAB_MEMBER(sp, buf)) {
1236 1236                          mutex_exit(&cp->cache_lock);
1237 1237                          return (sp);
1238 1238                  }
1239 1239          }
1240 1240          for (sp = avl_first(&cp->cache_partial_slabs); sp != NULL;
1241 1241              sp = AVL_NEXT(&cp->cache_partial_slabs, sp)) {
1242 1242                  if (KMEM_SLAB_MEMBER(sp, buf)) {
1243 1243                          mutex_exit(&cp->cache_lock);
1244 1244                          return (sp);
1245 1245                  }
1246 1246          }
1247 1247          mutex_exit(&cp->cache_lock);
1248 1248  
1249 1249          return (NULL);
1250 1250  }
1251 1251  
1252 1252  static void
1253 1253  kmem_error(int error, kmem_cache_t *cparg, void *bufarg)
1254 1254  {
1255 1255          kmem_buftag_t *btp = NULL;
1256 1256          kmem_bufctl_t *bcp = NULL;
1257 1257          kmem_cache_t *cp = cparg;
1258 1258          kmem_slab_t *sp;
1259 1259          uint64_t *off;
1260 1260          void *buf = bufarg;
1261 1261  
1262 1262          kmem_logging = 0;       /* stop logging when a bad thing happens */
1263 1263  
1264 1264          kmem_panic_info.kmp_timestamp = gethrtime();
1265 1265  
1266 1266          sp = kmem_findslab(cp, buf);
1267 1267          if (sp == NULL) {
1268 1268                  for (cp = list_tail(&kmem_caches); cp != NULL;
1269 1269                      cp = list_prev(&kmem_caches, cp)) {
1270 1270                          if ((sp = kmem_findslab(cp, buf)) != NULL)
1271 1271                                  break;
1272 1272                  }
1273 1273          }
1274 1274  
1275 1275          if (sp == NULL) {
1276 1276                  cp = NULL;
1277 1277                  error = KMERR_BADADDR;
1278 1278          } else {
1279 1279                  if (cp != cparg)
1280 1280                          error = KMERR_BADCACHE;
1281 1281                  else
1282 1282                          buf = (char *)bufarg - ((uintptr_t)bufarg -
1283 1283                              (uintptr_t)sp->slab_base) % cp->cache_chunksize;
1284 1284                  if (buf != bufarg)
1285 1285                          error = KMERR_BADBASE;
1286 1286                  if (cp->cache_flags & KMF_BUFTAG)
1287 1287                          btp = KMEM_BUFTAG(cp, buf);
1288 1288                  if (cp->cache_flags & KMF_HASH) {
1289 1289                          mutex_enter(&cp->cache_lock);
1290 1290                          for (bcp = *KMEM_HASH(cp, buf); bcp; bcp = bcp->bc_next)
1291 1291                                  if (bcp->bc_addr == buf)
1292 1292                                          break;
1293 1293                          mutex_exit(&cp->cache_lock);
1294 1294                          if (bcp == NULL && btp != NULL)
1295 1295                                  bcp = btp->bt_bufctl;
1296 1296                          if (kmem_findslab(cp->cache_bufctl_cache, bcp) ==
1297 1297                              NULL || P2PHASE((uintptr_t)bcp, KMEM_ALIGN) ||
1298 1298                              bcp->bc_addr != buf) {
1299 1299                                  error = KMERR_BADBUFCTL;
1300 1300                                  bcp = NULL;
1301 1301                          }
1302 1302                  }
1303 1303          }
1304 1304  
1305 1305          kmem_panic_info.kmp_error = error;
1306 1306          kmem_panic_info.kmp_buffer = bufarg;
1307 1307          kmem_panic_info.kmp_realbuf = buf;
1308 1308          kmem_panic_info.kmp_cache = cparg;
1309 1309          kmem_panic_info.kmp_realcache = cp;
1310 1310          kmem_panic_info.kmp_slab = sp;
1311 1311          kmem_panic_info.kmp_bufctl = bcp;
1312 1312  
1313 1313          printf("kernel memory allocator: ");
1314 1314  
1315 1315          switch (error) {
1316 1316  
1317 1317          case KMERR_MODIFIED:
1318 1318                  printf("buffer modified after being freed\n");
1319 1319                  off = verify_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify);
1320 1320                  if (off == NULL)        /* shouldn't happen */
1321 1321                          off = buf;
1322 1322                  printf("modification occurred at offset 0x%lx "
1323 1323                      "(0x%llx replaced by 0x%llx)\n",
1324 1324                      (uintptr_t)off - (uintptr_t)buf,
1325 1325                      (longlong_t)KMEM_FREE_PATTERN, (longlong_t)*off);
1326 1326                  break;
1327 1327  
1328 1328          case KMERR_REDZONE:
1329 1329                  printf("redzone violation: write past end of buffer\n");
1330 1330                  break;
1331 1331  
1332 1332          case KMERR_BADADDR:
1333 1333                  printf("invalid free: buffer not in cache\n");
1334 1334                  break;
1335 1335  
1336 1336          case KMERR_DUPFREE:
1337 1337                  printf("duplicate free: buffer freed twice\n");
1338 1338                  break;
1339 1339  
1340 1340          case KMERR_BADBUFTAG:
1341 1341                  printf("boundary tag corrupted\n");
1342 1342                  printf("bcp ^ bxstat = %lx, should be %lx\n",
1343 1343                      (intptr_t)btp->bt_bufctl ^ btp->bt_bxstat,
1344 1344                      KMEM_BUFTAG_FREE);
1345 1345                  break;
1346 1346  
1347 1347          case KMERR_BADBUFCTL:
1348 1348                  printf("bufctl corrupted\n");
1349 1349                  break;
1350 1350  
1351 1351          case KMERR_BADCACHE:
1352 1352                  printf("buffer freed to wrong cache\n");
1353 1353                  printf("buffer was allocated from %s,\n", cp->cache_name);
1354 1354                  printf("caller attempting free to %s.\n", cparg->cache_name);
1355 1355                  break;
1356 1356  
1357 1357          case KMERR_BADSIZE:
1358 1358                  printf("bad free: free size (%u) != alloc size (%u)\n",
1359 1359                      KMEM_SIZE_DECODE(((uint32_t *)btp)[0]),
1360 1360                      KMEM_SIZE_DECODE(((uint32_t *)btp)[1]));
1361 1361                  break;
1362 1362  
1363 1363          case KMERR_BADBASE:
1364 1364                  printf("bad free: free address (%p) != alloc address (%p)\n",
1365 1365                      bufarg, buf);
1366 1366                  break;
1367 1367          }
1368 1368  
1369 1369          printf("buffer=%p  bufctl=%p  cache: %s\n",
1370 1370              bufarg, (void *)bcp, cparg->cache_name);
1371 1371  
1372 1372          if (bcp != NULL && (cp->cache_flags & KMF_AUDIT) &&
1373 1373              error != KMERR_BADBUFCTL) {
1374 1374                  int d;
1375 1375                  timestruc_t ts;
1376 1376                  kmem_bufctl_audit_t *bcap = (kmem_bufctl_audit_t *)bcp;
1377 1377  
1378 1378                  hrt2ts(kmem_panic_info.kmp_timestamp - bcap->bc_timestamp, &ts);
1379 1379                  printf("previous transaction on buffer %p:\n", buf);
1380 1380                  printf("thread=%p  time=T-%ld.%09ld  slab=%p  cache: %s\n",
1381 1381                      (void *)bcap->bc_thread, ts.tv_sec, ts.tv_nsec,
1382 1382                      (void *)sp, cp->cache_name);
1383 1383                  for (d = 0; d < MIN(bcap->bc_depth, KMEM_STACK_DEPTH); d++) {
1384 1384                          ulong_t off;
1385 1385                          char *sym = kobj_getsymname(bcap->bc_stack[d], &off);
1386 1386                          printf("%s+%lx\n", sym ? sym : "?", off);
1387 1387                  }
1388 1388          }
1389 1389          if (kmem_panic > 0)
1390 1390                  panic("kernel heap corruption detected");
1391 1391          if (kmem_panic == 0)
1392 1392                  debug_enter(NULL);
1393 1393          kmem_logging = 1;       /* resume logging */
1394 1394  }
1395 1395  
1396 1396  static kmem_log_header_t *
1397 1397  kmem_log_init(size_t logsize)
1398 1398  {
1399 1399          kmem_log_header_t *lhp;
1400 1400          int nchunks = 4 * max_ncpus;
1401 1401          size_t lhsize = (size_t)&((kmem_log_header_t *)0)->lh_cpu[max_ncpus];
1402 1402          int i;
1403 1403  
1404 1404          /*
1405 1405           * Make sure that lhp->lh_cpu[] is nicely aligned
1406 1406           * to prevent false sharing of cache lines.
1407 1407           */
1408 1408          lhsize = P2ROUNDUP(lhsize, KMEM_ALIGN);
1409 1409          lhp = vmem_xalloc(kmem_log_arena, lhsize, 64, P2NPHASE(lhsize, 64), 0,
1410 1410              NULL, NULL, VM_SLEEP);
1411 1411          bzero(lhp, lhsize);
1412 1412  
1413 1413          mutex_init(&lhp->lh_lock, NULL, MUTEX_DEFAULT, NULL);
1414 1414          lhp->lh_nchunks = nchunks;
1415 1415          lhp->lh_chunksize = P2ROUNDUP(logsize / nchunks + 1, PAGESIZE);
1416 1416          lhp->lh_base = vmem_alloc(kmem_log_arena,
1417 1417              lhp->lh_chunksize * nchunks, VM_SLEEP);
1418 1418          lhp->lh_free = vmem_alloc(kmem_log_arena,
1419 1419              nchunks * sizeof (int), VM_SLEEP);
1420 1420          bzero(lhp->lh_base, lhp->lh_chunksize * nchunks);
1421 1421  
1422 1422          for (i = 0; i < max_ncpus; i++) {
1423 1423                  kmem_cpu_log_header_t *clhp = &lhp->lh_cpu[i];
1424 1424                  mutex_init(&clhp->clh_lock, NULL, MUTEX_DEFAULT, NULL);
1425 1425                  clhp->clh_chunk = i;
1426 1426          }
1427 1427  
1428 1428          for (i = max_ncpus; i < nchunks; i++)
1429 1429                  lhp->lh_free[i] = i;
1430 1430  
1431 1431          lhp->lh_head = max_ncpus;
1432 1432          lhp->lh_tail = 0;
1433 1433  
1434 1434          return (lhp);
1435 1435  }
1436 1436  
1437 1437  static void *
1438 1438  kmem_log_enter(kmem_log_header_t *lhp, void *data, size_t size)
1439 1439  {
1440 1440          void *logspace;
1441 1441          kmem_cpu_log_header_t *clhp;
1442 1442  
1443 1443          if (lhp == NULL || kmem_logging == 0 || panicstr)
1444 1444                  return (NULL);
1445 1445  
1446 1446          clhp = &lhp->lh_cpu[CPU->cpu_seqid];
1447 1447  
1448 1448          mutex_enter(&clhp->clh_lock);
1449 1449          clhp->clh_hits++;
1450 1450          if (size > clhp->clh_avail) {
1451 1451                  mutex_enter(&lhp->lh_lock);
1452 1452                  lhp->lh_hits++;
1453 1453                  lhp->lh_free[lhp->lh_tail] = clhp->clh_chunk;
1454 1454                  lhp->lh_tail = (lhp->lh_tail + 1) % lhp->lh_nchunks;
1455 1455                  clhp->clh_chunk = lhp->lh_free[lhp->lh_head];
1456 1456                  lhp->lh_head = (lhp->lh_head + 1) % lhp->lh_nchunks;
1457 1457                  clhp->clh_current = lhp->lh_base +
1458 1458                      clhp->clh_chunk * lhp->lh_chunksize;
1459 1459                  clhp->clh_avail = lhp->lh_chunksize;
1460 1460                  if (size > lhp->lh_chunksize)
1461 1461                          size = lhp->lh_chunksize;
1462 1462                  mutex_exit(&lhp->lh_lock);
1463 1463          }
1464 1464          logspace = clhp->clh_current;
1465 1465          clhp->clh_current += size;
1466 1466          clhp->clh_avail -= size;
1467 1467          bcopy(data, logspace, size);
1468 1468          mutex_exit(&clhp->clh_lock);
1469 1469          return (logspace);
1470 1470  }
1471 1471  
1472 1472  #define KMEM_AUDIT(lp, cp, bcp)                                         \
1473 1473  {                                                                       \
1474 1474          kmem_bufctl_audit_t *_bcp = (kmem_bufctl_audit_t *)(bcp);       \
1475 1475          _bcp->bc_timestamp = gethrtime();                               \
1476 1476          _bcp->bc_thread = curthread;                                    \
1477 1477          _bcp->bc_depth = getpcstack(_bcp->bc_stack, KMEM_STACK_DEPTH);  \
1478 1478          _bcp->bc_lastlog = kmem_log_enter((lp), _bcp, sizeof (*_bcp));  \
1479 1479  }
1480 1480  
1481 1481  static void
1482 1482  kmem_log_event(kmem_log_header_t *lp, kmem_cache_t *cp,
1483 1483      kmem_slab_t *sp, void *addr)
1484 1484  {
1485 1485          kmem_bufctl_audit_t bca;
1486 1486  
1487 1487          bzero(&bca, sizeof (kmem_bufctl_audit_t));
1488 1488          bca.bc_addr = addr;
1489 1489          bca.bc_slab = sp;
1490 1490          bca.bc_cache = cp;
1491 1491          KMEM_AUDIT(lp, cp, &bca);
1492 1492  }
1493 1493  
1494 1494  /*
1495 1495   * Create a new slab for cache cp.
1496 1496   */
1497 1497  static kmem_slab_t *
1498 1498  kmem_slab_create(kmem_cache_t *cp, int kmflag)
1499 1499  {
1500 1500          size_t slabsize = cp->cache_slabsize;
1501 1501          size_t chunksize = cp->cache_chunksize;
1502 1502          int cache_flags = cp->cache_flags;
1503 1503          size_t color, chunks;
1504 1504          char *buf, *slab;
1505 1505          kmem_slab_t *sp;
1506 1506          kmem_bufctl_t *bcp;
1507 1507          vmem_t *vmp = cp->cache_arena;
1508 1508  
1509 1509          ASSERT(MUTEX_NOT_HELD(&cp->cache_lock));
1510 1510  
1511 1511          color = cp->cache_color + cp->cache_align;
1512 1512          if (color > cp->cache_maxcolor)
1513 1513                  color = cp->cache_mincolor;
1514 1514          cp->cache_color = color;
1515 1515  
1516 1516          slab = vmem_alloc(vmp, slabsize, kmflag & KM_VMFLAGS);
1517 1517  
1518 1518          if (slab == NULL)
1519 1519                  goto vmem_alloc_failure;
1520 1520  
1521 1521          ASSERT(P2PHASE((uintptr_t)slab, vmp->vm_quantum) == 0);
1522 1522  
1523 1523          /*
1524 1524           * Reverify what was already checked in kmem_cache_set_move(), since the
1525 1525           * consolidator depends (for correctness) on slabs being initialized
1526 1526           * with the 0xbaddcafe memory pattern (setting a low order bit usable by
1527 1527           * clients to distinguish uninitialized memory from known objects).
1528 1528           */
1529 1529          ASSERT((cp->cache_move == NULL) || !(cp->cache_cflags & KMC_NOTOUCH));
1530 1530          if (!(cp->cache_cflags & KMC_NOTOUCH))
1531 1531                  copy_pattern(KMEM_UNINITIALIZED_PATTERN, slab, slabsize);
1532 1532  
1533 1533          if (cache_flags & KMF_HASH) {
1534 1534                  if ((sp = kmem_cache_alloc(kmem_slab_cache, kmflag)) == NULL)
1535 1535                          goto slab_alloc_failure;
1536 1536                  chunks = (slabsize - color) / chunksize;
1537 1537          } else {
1538 1538                  sp = KMEM_SLAB(cp, slab);
1539 1539                  chunks = (slabsize - sizeof (kmem_slab_t) - color) / chunksize;
1540 1540          }
1541 1541  
1542 1542          sp->slab_cache  = cp;
1543 1543          sp->slab_head   = NULL;
1544 1544          sp->slab_refcnt = 0;
1545 1545          sp->slab_base   = buf = slab + color;
1546 1546          sp->slab_chunks = chunks;
1547 1547          sp->slab_stuck_offset = (uint32_t)-1;
1548 1548          sp->slab_later_count = 0;
1549 1549          sp->slab_flags = 0;
1550 1550  
1551 1551          ASSERT(chunks > 0);
1552 1552          while (chunks-- != 0) {
1553 1553                  if (cache_flags & KMF_HASH) {
1554 1554                          bcp = kmem_cache_alloc(cp->cache_bufctl_cache, kmflag);
1555 1555                          if (bcp == NULL)
1556 1556                                  goto bufctl_alloc_failure;
1557 1557                          if (cache_flags & KMF_AUDIT) {
1558 1558                                  kmem_bufctl_audit_t *bcap =
1559 1559                                      (kmem_bufctl_audit_t *)bcp;
1560 1560                                  bzero(bcap, sizeof (kmem_bufctl_audit_t));
1561 1561                                  bcap->bc_cache = cp;
1562 1562                          }
1563 1563                          bcp->bc_addr = buf;
1564 1564                          bcp->bc_slab = sp;
1565 1565                  } else {
1566 1566                          bcp = KMEM_BUFCTL(cp, buf);
1567 1567                  }
1568 1568                  if (cache_flags & KMF_BUFTAG) {
1569 1569                          kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
1570 1570                          btp->bt_redzone = KMEM_REDZONE_PATTERN;
1571 1571                          btp->bt_bufctl = bcp;
1572 1572                          btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_FREE;
1573 1573                          if (cache_flags & KMF_DEADBEEF) {
1574 1574                                  copy_pattern(KMEM_FREE_PATTERN, buf,
1575 1575                                      cp->cache_verify);
1576 1576                          }
1577 1577                  }
1578 1578                  bcp->bc_next = sp->slab_head;
1579 1579                  sp->slab_head = bcp;
1580 1580                  buf += chunksize;
1581 1581          }
1582 1582  
1583 1583          kmem_log_event(kmem_slab_log, cp, sp, slab);
1584 1584  
1585 1585          return (sp);
1586 1586  
1587 1587  bufctl_alloc_failure:
1588 1588  
1589 1589          while ((bcp = sp->slab_head) != NULL) {
1590 1590                  sp->slab_head = bcp->bc_next;
1591 1591                  kmem_cache_free(cp->cache_bufctl_cache, bcp);
1592 1592          }
1593 1593          kmem_cache_free(kmem_slab_cache, sp);
1594 1594  
1595 1595  slab_alloc_failure:
1596 1596  
1597 1597          vmem_free(vmp, slab, slabsize);
1598 1598  
1599 1599  vmem_alloc_failure:
1600 1600  
1601 1601          kmem_log_event(kmem_failure_log, cp, NULL, NULL);
1602 1602          atomic_inc_64(&cp->cache_alloc_fail);
1603 1603  
1604 1604          return (NULL);
1605 1605  }
1606 1606  
1607 1607  /*
1608 1608   * Destroy a slab.
1609 1609   */
1610 1610  static void
1611 1611  kmem_slab_destroy(kmem_cache_t *cp, kmem_slab_t *sp)
1612 1612  {
1613 1613          vmem_t *vmp = cp->cache_arena;
1614 1614          void *slab = (void *)P2ALIGN((uintptr_t)sp->slab_base, vmp->vm_quantum);
1615 1615  
1616 1616          ASSERT(MUTEX_NOT_HELD(&cp->cache_lock));
1617 1617          ASSERT(sp->slab_refcnt == 0);
1618 1618  
1619 1619          if (cp->cache_flags & KMF_HASH) {
1620 1620                  kmem_bufctl_t *bcp;
1621 1621                  while ((bcp = sp->slab_head) != NULL) {
1622 1622                          sp->slab_head = bcp->bc_next;
1623 1623                          kmem_cache_free(cp->cache_bufctl_cache, bcp);
1624 1624                  }
1625 1625                  kmem_cache_free(kmem_slab_cache, sp);
1626 1626          }
1627 1627          vmem_free(vmp, slab, cp->cache_slabsize);
1628 1628  }
1629 1629  
1630 1630  static void *
1631 1631  kmem_slab_alloc_impl(kmem_cache_t *cp, kmem_slab_t *sp, boolean_t prefill)
1632 1632  {
1633 1633          kmem_bufctl_t *bcp, **hash_bucket;
1634 1634          void *buf;
1635 1635          boolean_t new_slab = (sp->slab_refcnt == 0);
1636 1636  
1637 1637          ASSERT(MUTEX_HELD(&cp->cache_lock));
1638 1638          /*
1639 1639           * kmem_slab_alloc() drops cache_lock when it creates a new slab, so we
1640 1640           * can't ASSERT(avl_is_empty(&cp->cache_partial_slabs)) here when the
1641 1641           * slab is newly created.
1642 1642           */
1643 1643          ASSERT(new_slab || (KMEM_SLAB_IS_PARTIAL(sp) &&
1644 1644              (sp == avl_first(&cp->cache_partial_slabs))));
1645 1645          ASSERT(sp->slab_cache == cp);
1646 1646  
1647 1647          cp->cache_slab_alloc++;
1648 1648          cp->cache_bufslab--;
1649 1649          sp->slab_refcnt++;
1650 1650  
1651 1651          bcp = sp->slab_head;
1652 1652          sp->slab_head = bcp->bc_next;
1653 1653  
1654 1654          if (cp->cache_flags & KMF_HASH) {
1655 1655                  /*
1656 1656                   * Add buffer to allocated-address hash table.
1657 1657                   */
1658 1658                  buf = bcp->bc_addr;
1659 1659                  hash_bucket = KMEM_HASH(cp, buf);
1660 1660                  bcp->bc_next = *hash_bucket;
1661 1661                  *hash_bucket = bcp;
1662 1662                  if ((cp->cache_flags & (KMF_AUDIT | KMF_BUFTAG)) == KMF_AUDIT) {
1663 1663                          KMEM_AUDIT(kmem_transaction_log, cp, bcp);
1664 1664                  }
1665 1665          } else {
1666 1666                  buf = KMEM_BUF(cp, bcp);
1667 1667          }
1668 1668  
1669 1669          ASSERT(KMEM_SLAB_MEMBER(sp, buf));
1670 1670  
1671 1671          if (sp->slab_head == NULL) {
1672 1672                  ASSERT(KMEM_SLAB_IS_ALL_USED(sp));
1673 1673                  if (new_slab) {
1674 1674                          ASSERT(sp->slab_chunks == 1);
1675 1675                  } else {
1676 1676                          ASSERT(sp->slab_chunks > 1); /* the slab was partial */
1677 1677                          avl_remove(&cp->cache_partial_slabs, sp);
1678 1678                          sp->slab_later_count = 0; /* clear history */
1679 1679                          sp->slab_flags &= ~KMEM_SLAB_NOMOVE;
1680 1680                          sp->slab_stuck_offset = (uint32_t)-1;
1681 1681                  }
1682 1682                  list_insert_head(&cp->cache_complete_slabs, sp);
1683 1683                  cp->cache_complete_slab_count++;
1684 1684                  return (buf);
1685 1685          }
1686 1686  
1687 1687          ASSERT(KMEM_SLAB_IS_PARTIAL(sp));
1688 1688          /*
1689 1689           * Peek to see if the magazine layer is enabled before
1690 1690           * we prefill.  We're not holding the cpu cache lock,
1691 1691           * so the peek could be wrong, but there's no harm in it.
1692 1692           */
1693 1693          if (new_slab && prefill && (cp->cache_flags & KMF_PREFILL) &&
1694 1694              (KMEM_CPU_CACHE(cp)->cc_magsize != 0))  {
1695 1695                  kmem_slab_prefill(cp, sp);
1696 1696                  return (buf);
1697 1697          }
1698 1698  
1699 1699          if (new_slab) {
1700 1700                  avl_add(&cp->cache_partial_slabs, sp);
1701 1701                  return (buf);
1702 1702          }
1703 1703  
1704 1704          /*
1705 1705           * The slab is now more allocated than it was, so the
1706 1706           * order remains unchanged.
1707 1707           */
1708 1708          ASSERT(!avl_update(&cp->cache_partial_slabs, sp));
1709 1709          return (buf);
1710 1710  }
1711 1711  
1712 1712  /*
1713 1713   * Allocate a raw (unconstructed) buffer from cp's slab layer.
1714 1714   */
1715 1715  static void *
1716 1716  kmem_slab_alloc(kmem_cache_t *cp, int kmflag)
1717 1717  {
1718 1718          kmem_slab_t *sp;
1719 1719          void *buf;
1720 1720          boolean_t test_destructor;
1721 1721  
1722 1722          mutex_enter(&cp->cache_lock);
1723 1723          test_destructor = (cp->cache_slab_alloc == 0);
1724 1724          sp = avl_first(&cp->cache_partial_slabs);
1725 1725          if (sp == NULL) {
1726 1726                  ASSERT(cp->cache_bufslab == 0);
1727 1727  
1728 1728                  /*
1729 1729                   * The freelist is empty.  Create a new slab.
1730 1730                   */
1731 1731                  mutex_exit(&cp->cache_lock);
1732 1732                  if ((sp = kmem_slab_create(cp, kmflag)) == NULL) {
1733 1733                          return (NULL);
1734 1734                  }
1735 1735                  mutex_enter(&cp->cache_lock);
1736 1736                  cp->cache_slab_create++;
1737 1737                  if ((cp->cache_buftotal += sp->slab_chunks) > cp->cache_bufmax)
1738 1738                          cp->cache_bufmax = cp->cache_buftotal;
1739 1739                  cp->cache_bufslab += sp->slab_chunks;
1740 1740          }
1741 1741  
1742 1742          buf = kmem_slab_alloc_impl(cp, sp, B_TRUE);
1743 1743          ASSERT((cp->cache_slab_create - cp->cache_slab_destroy) ==
1744 1744              (cp->cache_complete_slab_count +
1745 1745              avl_numnodes(&cp->cache_partial_slabs) +
1746 1746              (cp->cache_defrag == NULL ? 0 : cp->cache_defrag->kmd_deadcount)));
1747 1747          mutex_exit(&cp->cache_lock);
1748 1748  
1749 1749          if (test_destructor && cp->cache_destructor != NULL) {
1750 1750                  /*
1751 1751                   * On the first kmem_slab_alloc(), assert that it is valid to
1752 1752                   * call the destructor on a newly constructed object without any
1753 1753                   * client involvement.
1754 1754                   */
1755 1755                  if ((cp->cache_constructor == NULL) ||
1756 1756                      cp->cache_constructor(buf, cp->cache_private,
1757 1757                      kmflag) == 0) {
1758 1758                          cp->cache_destructor(buf, cp->cache_private);
1759 1759                  }
1760 1760                  copy_pattern(KMEM_UNINITIALIZED_PATTERN, buf,
1761 1761                      cp->cache_bufsize);
1762 1762                  if (cp->cache_flags & KMF_DEADBEEF) {
1763 1763                          copy_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify);
1764 1764                  }
1765 1765          }
1766 1766  
1767 1767          return (buf);
1768 1768  }
1769 1769  
1770 1770  static void kmem_slab_move_yes(kmem_cache_t *, kmem_slab_t *, void *);
1771 1771  
1772 1772  /*
1773 1773   * Free a raw (unconstructed) buffer to cp's slab layer.
1774 1774   */
1775 1775  static void
1776 1776  kmem_slab_free(kmem_cache_t *cp, void *buf)
1777 1777  {
1778 1778          kmem_slab_t *sp;
1779 1779          kmem_bufctl_t *bcp, **prev_bcpp;
1780 1780  
1781 1781          ASSERT(buf != NULL);
1782 1782  
1783 1783          mutex_enter(&cp->cache_lock);
1784 1784          cp->cache_slab_free++;
1785 1785  
1786 1786          if (cp->cache_flags & KMF_HASH) {
1787 1787                  /*
1788 1788                   * Look up buffer in allocated-address hash table.
1789 1789                   */
1790 1790                  prev_bcpp = KMEM_HASH(cp, buf);
1791 1791                  while ((bcp = *prev_bcpp) != NULL) {
1792 1792                          if (bcp->bc_addr == buf) {
1793 1793                                  *prev_bcpp = bcp->bc_next;
1794 1794                                  sp = bcp->bc_slab;
1795 1795                                  break;
1796 1796                          }
1797 1797                          cp->cache_lookup_depth++;
1798 1798                          prev_bcpp = &bcp->bc_next;
1799 1799                  }
1800 1800          } else {
1801 1801                  bcp = KMEM_BUFCTL(cp, buf);
1802 1802                  sp = KMEM_SLAB(cp, buf);
1803 1803          }
1804 1804  
1805 1805          if (bcp == NULL || sp->slab_cache != cp || !KMEM_SLAB_MEMBER(sp, buf)) {
1806 1806                  mutex_exit(&cp->cache_lock);
1807 1807                  kmem_error(KMERR_BADADDR, cp, buf);
1808 1808                  return;
1809 1809          }
1810 1810  
1811 1811          if (KMEM_SLAB_OFFSET(sp, buf) == sp->slab_stuck_offset) {
1812 1812                  /*
1813 1813                   * If this is the buffer that prevented the consolidator from
1814 1814                   * clearing the slab, we can reset the slab flags now that the
1815 1815                   * buffer is freed. (It makes sense to do this in
1816 1816                   * kmem_cache_free(), where the client gives up ownership of the
1817 1817                   * buffer, but on the hot path the test is too expensive.)
1818 1818                   */
1819 1819                  kmem_slab_move_yes(cp, sp, buf);
1820 1820          }
1821 1821  
1822 1822          if ((cp->cache_flags & (KMF_AUDIT | KMF_BUFTAG)) == KMF_AUDIT) {
1823 1823                  if (cp->cache_flags & KMF_CONTENTS)
1824 1824                          ((kmem_bufctl_audit_t *)bcp)->bc_contents =
1825 1825                              kmem_log_enter(kmem_content_log, buf,
1826 1826                              cp->cache_contents);
1827 1827                  KMEM_AUDIT(kmem_transaction_log, cp, bcp);
1828 1828          }
1829 1829  
1830 1830          bcp->bc_next = sp->slab_head;
1831 1831          sp->slab_head = bcp;
1832 1832  
1833 1833          cp->cache_bufslab++;
1834 1834          ASSERT(sp->slab_refcnt >= 1);
1835 1835  
1836 1836          if (--sp->slab_refcnt == 0) {
1837 1837                  /*
1838 1838                   * There are no outstanding allocations from this slab,
1839 1839                   * so we can reclaim the memory.
1840 1840                   */
1841 1841                  if (sp->slab_chunks == 1) {
1842 1842                          list_remove(&cp->cache_complete_slabs, sp);
1843 1843                          cp->cache_complete_slab_count--;
1844 1844                  } else {
1845 1845                          avl_remove(&cp->cache_partial_slabs, sp);
1846 1846                  }
1847 1847  
1848 1848                  cp->cache_buftotal -= sp->slab_chunks;
1849 1849                  cp->cache_bufslab -= sp->slab_chunks;
1850 1850                  /*
1851 1851                   * Defer releasing the slab to the virtual memory subsystem
1852 1852                   * while there is a pending move callback, since we guarantee
1853 1853                   * that buffers passed to the move callback have only been
1854 1854                   * touched by kmem or by the client itself. Since the memory
1855 1855                   * patterns baddcafe (uninitialized) and deadbeef (freed) both
1856 1856                   * set at least one of the two lowest order bits, the client can
1857 1857                   * test those bits in the move callback to determine whether or
1858 1858                   * not it knows about the buffer (assuming that the client also
1859 1859                   * sets one of those low order bits whenever it frees a buffer).
1860 1860                   */
1861 1861                  if (cp->cache_defrag == NULL ||
1862 1862                      (avl_is_empty(&cp->cache_defrag->kmd_moves_pending) &&
1863 1863                      !(sp->slab_flags & KMEM_SLAB_MOVE_PENDING))) {
1864 1864                          cp->cache_slab_destroy++;
1865 1865                          mutex_exit(&cp->cache_lock);
1866 1866                          kmem_slab_destroy(cp, sp);
1867 1867                  } else {
1868 1868                          list_t *deadlist = &cp->cache_defrag->kmd_deadlist;
1869 1869                          /*
1870 1870                           * Slabs are inserted at both ends of the deadlist to
1871 1871                           * distinguish between slabs freed while move callbacks
1872 1872                           * are pending (list head) and a slab freed while the
1873 1873                           * lock is dropped in kmem_move_buffers() (list tail) so
1874 1874                           * that in both cases slab_destroy() is called from the
1875 1875                           * right context.
1876 1876                           */
1877 1877                          if (sp->slab_flags & KMEM_SLAB_MOVE_PENDING) {
1878 1878                                  list_insert_tail(deadlist, sp);
1879 1879                          } else {
1880 1880                                  list_insert_head(deadlist, sp);
1881 1881                          }
1882 1882                          cp->cache_defrag->kmd_deadcount++;
1883 1883                          mutex_exit(&cp->cache_lock);
1884 1884                  }
1885 1885                  return;
1886 1886          }
1887 1887  
1888 1888          if (bcp->bc_next == NULL) {
1889 1889                  /* Transition the slab from completely allocated to partial. */
1890 1890                  ASSERT(sp->slab_refcnt == (sp->slab_chunks - 1));
1891 1891                  ASSERT(sp->slab_chunks > 1);
1892 1892                  list_remove(&cp->cache_complete_slabs, sp);
1893 1893                  cp->cache_complete_slab_count--;
1894 1894                  avl_add(&cp->cache_partial_slabs, sp);
1895 1895          } else {
1896 1896                  (void) avl_update_gt(&cp->cache_partial_slabs, sp);
1897 1897          }
1898 1898  
1899 1899          ASSERT((cp->cache_slab_create - cp->cache_slab_destroy) ==
1900 1900              (cp->cache_complete_slab_count +
1901 1901              avl_numnodes(&cp->cache_partial_slabs) +
1902 1902              (cp->cache_defrag == NULL ? 0 : cp->cache_defrag->kmd_deadcount)));
1903 1903          mutex_exit(&cp->cache_lock);
1904 1904  }
1905 1905  
1906 1906  /*
1907 1907   * Return -1 if kmem_error, 1 if constructor fails, 0 if successful.
1908 1908   */
1909 1909  static int
1910 1910  kmem_cache_alloc_debug(kmem_cache_t *cp, void *buf, int kmflag, int construct,
1911 1911      caddr_t caller)
1912 1912  {
1913 1913          kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
1914 1914          kmem_bufctl_audit_t *bcp = (kmem_bufctl_audit_t *)btp->bt_bufctl;
1915 1915          uint32_t mtbf;
1916 1916  
1917 1917          if (btp->bt_bxstat != ((intptr_t)bcp ^ KMEM_BUFTAG_FREE)) {
1918 1918                  kmem_error(KMERR_BADBUFTAG, cp, buf);
1919 1919                  return (-1);
1920 1920          }
1921 1921  
1922 1922          btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_ALLOC;
1923 1923  
1924 1924          if ((cp->cache_flags & KMF_HASH) && bcp->bc_addr != buf) {
1925 1925                  kmem_error(KMERR_BADBUFCTL, cp, buf);
1926 1926                  return (-1);
1927 1927          }
1928 1928  
1929 1929          if (cp->cache_flags & KMF_DEADBEEF) {
1930 1930                  if (!construct && (cp->cache_flags & KMF_LITE)) {
1931 1931                          if (*(uint64_t *)buf != KMEM_FREE_PATTERN) {
1932 1932                                  kmem_error(KMERR_MODIFIED, cp, buf);
1933 1933                                  return (-1);
1934 1934                          }
1935 1935                          if (cp->cache_constructor != NULL)
1936 1936                                  *(uint64_t *)buf = btp->bt_redzone;
1937 1937                          else
1938 1938                                  *(uint64_t *)buf = KMEM_UNINITIALIZED_PATTERN;
1939 1939                  } else {
1940 1940                          construct = 1;
1941 1941                          if (verify_and_copy_pattern(KMEM_FREE_PATTERN,
1942 1942                              KMEM_UNINITIALIZED_PATTERN, buf,
1943 1943                              cp->cache_verify)) {
1944 1944                                  kmem_error(KMERR_MODIFIED, cp, buf);
1945 1945                                  return (-1);
1946 1946                          }
1947 1947                  }
1948 1948          }
1949 1949          btp->bt_redzone = KMEM_REDZONE_PATTERN;
1950 1950  
1951 1951          if ((mtbf = kmem_mtbf | cp->cache_mtbf) != 0 &&
1952 1952              gethrtime() % mtbf == 0 &&
1953 1953              (kmflag & (KM_NOSLEEP | KM_PANIC)) == KM_NOSLEEP) {
1954 1954                  kmem_log_event(kmem_failure_log, cp, NULL, NULL);
1955 1955                  if (!construct && cp->cache_destructor != NULL)
1956 1956                          cp->cache_destructor(buf, cp->cache_private);
1957 1957          } else {
1958 1958                  mtbf = 0;
1959 1959          }
1960 1960  
1961 1961          if (mtbf || (construct && cp->cache_constructor != NULL &&
1962 1962              cp->cache_constructor(buf, cp->cache_private, kmflag) != 0)) {
1963 1963                  atomic_inc_64(&cp->cache_alloc_fail);
1964 1964                  btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_FREE;
1965 1965                  if (cp->cache_flags & KMF_DEADBEEF)
1966 1966                          copy_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify);
1967 1967                  kmem_slab_free(cp, buf);
1968 1968                  return (1);
1969 1969          }
1970 1970  
1971 1971          if (cp->cache_flags & KMF_AUDIT) {
1972 1972                  KMEM_AUDIT(kmem_transaction_log, cp, bcp);
1973 1973          }
1974 1974  
1975 1975          if ((cp->cache_flags & KMF_LITE) &&
1976 1976              !(cp->cache_cflags & KMC_KMEM_ALLOC)) {
1977 1977                  KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, caller);
1978 1978          }
1979 1979  
1980 1980          return (0);
1981 1981  }
1982 1982  
1983 1983  static int
1984 1984  kmem_cache_free_debug(kmem_cache_t *cp, void *buf, caddr_t caller)
1985 1985  {
1986 1986          kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
1987 1987          kmem_bufctl_audit_t *bcp = (kmem_bufctl_audit_t *)btp->bt_bufctl;
1988 1988          kmem_slab_t *sp;
1989 1989  
1990 1990          if (btp->bt_bxstat != ((intptr_t)bcp ^ KMEM_BUFTAG_ALLOC)) {
1991 1991                  if (btp->bt_bxstat == ((intptr_t)bcp ^ KMEM_BUFTAG_FREE)) {
1992 1992                          kmem_error(KMERR_DUPFREE, cp, buf);
1993 1993                          return (-1);
1994 1994                  }
1995 1995                  sp = kmem_findslab(cp, buf);
1996 1996                  if (sp == NULL || sp->slab_cache != cp)
1997 1997                          kmem_error(KMERR_BADADDR, cp, buf);
1998 1998                  else
1999 1999                          kmem_error(KMERR_REDZONE, cp, buf);
2000 2000                  return (-1);
2001 2001          }
2002 2002  
2003 2003          btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_FREE;
2004 2004  
2005 2005          if ((cp->cache_flags & KMF_HASH) && bcp->bc_addr != buf) {
2006 2006                  kmem_error(KMERR_BADBUFCTL, cp, buf);
2007 2007                  return (-1);
2008 2008          }
2009 2009  
2010 2010          if (btp->bt_redzone != KMEM_REDZONE_PATTERN) {
2011 2011                  kmem_error(KMERR_REDZONE, cp, buf);
2012 2012                  return (-1);
2013 2013          }
2014 2014  
2015 2015          if (cp->cache_flags & KMF_AUDIT) {
2016 2016                  if (cp->cache_flags & KMF_CONTENTS)
2017 2017                          bcp->bc_contents = kmem_log_enter(kmem_content_log,
2018 2018                              buf, cp->cache_contents);
2019 2019                  KMEM_AUDIT(kmem_transaction_log, cp, bcp);
2020 2020          }
2021 2021  
2022 2022          if ((cp->cache_flags & KMF_LITE) &&
2023 2023              !(cp->cache_cflags & KMC_KMEM_ALLOC)) {
2024 2024                  KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, caller);
2025 2025          }
2026 2026  
2027 2027          if (cp->cache_flags & KMF_DEADBEEF) {
2028 2028                  if (cp->cache_flags & KMF_LITE)
2029 2029                          btp->bt_redzone = *(uint64_t *)buf;
2030 2030                  else if (cp->cache_destructor != NULL)
2031 2031                          cp->cache_destructor(buf, cp->cache_private);
2032 2032  
2033 2033                  copy_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify);
2034 2034          }
2035 2035  
2036 2036          return (0);
2037 2037  }
2038 2038  
2039 2039  /*
2040 2040   * Free each object in magazine mp to cp's slab layer, and free mp itself.
2041 2041   */
2042 2042  static void
2043 2043  kmem_magazine_destroy(kmem_cache_t *cp, kmem_magazine_t *mp, int nrounds)
2044 2044  {
2045 2045          int round;
2046 2046  
2047 2047          ASSERT(!list_link_active(&cp->cache_link) ||
2048 2048              taskq_member(kmem_taskq, curthread));
2049 2049  
2050 2050          for (round = 0; round < nrounds; round++) {
2051 2051                  void *buf = mp->mag_round[round];
2052 2052  
2053 2053                  if (cp->cache_flags & KMF_DEADBEEF) {
2054 2054                          if (verify_pattern(KMEM_FREE_PATTERN, buf,
2055 2055                              cp->cache_verify) != NULL) {
2056 2056                                  kmem_error(KMERR_MODIFIED, cp, buf);
2057 2057                                  continue;
2058 2058                          }
2059 2059                          if ((cp->cache_flags & KMF_LITE) &&
2060 2060                              cp->cache_destructor != NULL) {
2061 2061                                  kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
2062 2062                                  *(uint64_t *)buf = btp->bt_redzone;
2063 2063                                  cp->cache_destructor(buf, cp->cache_private);
2064 2064                                  *(uint64_t *)buf = KMEM_FREE_PATTERN;
2065 2065                          }
2066 2066                  } else if (cp->cache_destructor != NULL) {
2067 2067                          cp->cache_destructor(buf, cp->cache_private);
2068 2068                  }
2069 2069  
2070 2070                  kmem_slab_free(cp, buf);
2071 2071          }
2072 2072          ASSERT(KMEM_MAGAZINE_VALID(cp, mp));
2073 2073          kmem_cache_free(cp->cache_magtype->mt_cache, mp);
2074 2074  }
2075 2075  
2076 2076  /*
2077 2077   * Allocate a magazine from the depot.
2078 2078   */
2079 2079  static kmem_magazine_t *
2080 2080  kmem_depot_alloc(kmem_cache_t *cp, kmem_maglist_t *mlp)
2081 2081  {
2082 2082          kmem_magazine_t *mp;
2083 2083  
2084 2084          /*
2085 2085           * If we can't get the depot lock without contention,
2086 2086           * update our contention count.  We use the depot
2087 2087           * contention rate to determine whether we need to
2088 2088           * increase the magazine size for better scalability.
2089 2089           */
2090 2090          if (!mutex_tryenter(&cp->cache_depot_lock)) {
2091 2091                  mutex_enter(&cp->cache_depot_lock);
2092 2092                  cp->cache_depot_contention++;
2093 2093          }
2094 2094  
2095 2095          if ((mp = mlp->ml_list) != NULL) {
2096 2096                  ASSERT(KMEM_MAGAZINE_VALID(cp, mp));
2097 2097                  mlp->ml_list = mp->mag_next;
2098 2098                  if (--mlp->ml_total < mlp->ml_min)
2099 2099                          mlp->ml_min = mlp->ml_total;
2100 2100                  mlp->ml_alloc++;
2101 2101          }
2102 2102  
2103 2103          mutex_exit(&cp->cache_depot_lock);
2104 2104  
2105 2105          return (mp);
2106 2106  }
2107 2107  
2108 2108  /*
2109 2109   * Free a magazine to the depot.
2110 2110   */
2111 2111  static void
2112 2112  kmem_depot_free(kmem_cache_t *cp, kmem_maglist_t *mlp, kmem_magazine_t *mp)
2113 2113  {
2114 2114          mutex_enter(&cp->cache_depot_lock);
2115 2115          ASSERT(KMEM_MAGAZINE_VALID(cp, mp));
2116 2116          mp->mag_next = mlp->ml_list;
2117 2117          mlp->ml_list = mp;
2118 2118          mlp->ml_total++;
2119 2119          mutex_exit(&cp->cache_depot_lock);
2120 2120  }
2121 2121  
2122 2122  /*
2123 2123   * Update the working set statistics for cp's depot.
2124 2124   */
2125 2125  static void
2126 2126  kmem_depot_ws_update(kmem_cache_t *cp)
2127 2127  {
2128 2128          mutex_enter(&cp->cache_depot_lock);
2129 2129          cp->cache_full.ml_reaplimit = cp->cache_full.ml_min;
2130 2130          cp->cache_full.ml_min = cp->cache_full.ml_total;
2131 2131          cp->cache_empty.ml_reaplimit = cp->cache_empty.ml_min;
2132 2132          cp->cache_empty.ml_min = cp->cache_empty.ml_total;
2133 2133          mutex_exit(&cp->cache_depot_lock);
2134 2134  }
2135 2135  
2136 2136  /*
2137 2137   * Set the working set statistics for cp's depot to zero.  (Everything is
2138 2138   * eligible for reaping.)
2139 2139   */
2140 2140  static void
2141 2141  kmem_depot_ws_zero(kmem_cache_t *cp)
2142 2142  {
2143 2143          mutex_enter(&cp->cache_depot_lock);
2144 2144          cp->cache_full.ml_reaplimit = cp->cache_full.ml_total;
2145 2145          cp->cache_full.ml_min = cp->cache_full.ml_total;
2146 2146          cp->cache_empty.ml_reaplimit = cp->cache_empty.ml_total;
2147 2147          cp->cache_empty.ml_min = cp->cache_empty.ml_total;
2148 2148          mutex_exit(&cp->cache_depot_lock);
2149 2149  }
2150 2150  
2151 2151  /*
2152 2152   * The number of bytes to reap before we call kpreempt(). The default (1MB)
2153 2153   * causes us to preempt reaping up to hundreds of times per second. Using a
2154 2154   * larger value (1GB) causes this to have virtually no effect.
2155 2155   */
2156 2156  size_t kmem_reap_preempt_bytes = 1024 * 1024;
2157 2157  
2158 2158  /*
2159 2159   * Reap all magazines that have fallen out of the depot's working set.
2160 2160   */
2161 2161  static void
2162 2162  kmem_depot_ws_reap(kmem_cache_t *cp)
2163 2163  {
2164 2164          size_t bytes = 0;
2165 2165          long reap;
2166 2166          kmem_magazine_t *mp;
2167 2167  
2168 2168          ASSERT(!list_link_active(&cp->cache_link) ||
2169 2169              taskq_member(kmem_taskq, curthread));
2170 2170  
2171 2171          reap = MIN(cp->cache_full.ml_reaplimit, cp->cache_full.ml_min);
2172 2172          while (reap-- &&
2173 2173              (mp = kmem_depot_alloc(cp, &cp->cache_full)) != NULL) {
2174 2174                  kmem_magazine_destroy(cp, mp, cp->cache_magtype->mt_magsize);
2175 2175                  bytes += cp->cache_magtype->mt_magsize * cp->cache_bufsize;
2176 2176                  if (bytes > kmem_reap_preempt_bytes) {
2177 2177                          kpreempt(KPREEMPT_SYNC);
2178 2178                          bytes = 0;
2179 2179                  }
2180 2180          }
2181 2181  
2182 2182          reap = MIN(cp->cache_empty.ml_reaplimit, cp->cache_empty.ml_min);
2183 2183          while (reap-- &&
2184 2184              (mp = kmem_depot_alloc(cp, &cp->cache_empty)) != NULL) {
2185 2185                  kmem_magazine_destroy(cp, mp, 0);
2186 2186                  bytes += cp->cache_magtype->mt_magsize * cp->cache_bufsize;
2187 2187                  if (bytes > kmem_reap_preempt_bytes) {
2188 2188                          kpreempt(KPREEMPT_SYNC);
2189 2189                          bytes = 0;
2190 2190                  }
2191 2191          }
2192 2192  }
2193 2193  
2194 2194  static void
2195 2195  kmem_cpu_reload(kmem_cpu_cache_t *ccp, kmem_magazine_t *mp, int rounds)
2196 2196  {
2197 2197          ASSERT((ccp->cc_loaded == NULL && ccp->cc_rounds == -1) ||
2198 2198              (ccp->cc_loaded && ccp->cc_rounds + rounds == ccp->cc_magsize));
2199 2199          ASSERT(ccp->cc_magsize > 0);
2200 2200  
2201 2201          ccp->cc_ploaded = ccp->cc_loaded;
2202 2202          ccp->cc_prounds = ccp->cc_rounds;
2203 2203          ccp->cc_loaded = mp;
2204 2204          ccp->cc_rounds = rounds;
2205 2205  }
2206 2206  
2207 2207  /*
2208 2208   * Intercept kmem alloc/free calls during crash dump in order to avoid
2209 2209   * changing kmem state while memory is being saved to the dump device.
2210 2210   * Otherwise, ::kmem_verify will report "corrupt buffers".  Note that
2211 2211   * there are no locks because only one CPU calls kmem during a crash
2212 2212   * dump. To enable this feature, first create the associated vmem
2213 2213   * arena with VMC_DUMPSAFE.
2214 2214   */
2215 2215  static void *kmem_dump_start;   /* start of pre-reserved heap */
2216 2216  static void *kmem_dump_end;     /* end of heap area */
2217 2217  static void *kmem_dump_curr;    /* current free heap pointer */
2218 2218  static size_t kmem_dump_size;   /* size of heap area */
2219 2219  
2220 2220  /* append to each buf created in the pre-reserved heap */
2221 2221  typedef struct kmem_dumpctl {
2222 2222          void    *kdc_next;      /* cache dump free list linkage */
2223 2223  } kmem_dumpctl_t;
2224 2224  
2225 2225  #define KMEM_DUMPCTL(cp, buf)   \
2226 2226          ((kmem_dumpctl_t *)P2ROUNDUP((uintptr_t)(buf) + (cp)->cache_bufsize, \
2227 2227              sizeof (void *)))
2228 2228  
2229 2229  /* set non zero for full report */
2230 2230  uint_t kmem_dump_verbose = 0;
2231 2231  
2232 2232  /* stats for overize heap */
2233 2233  uint_t kmem_dump_oversize_allocs = 0;
2234 2234  uint_t kmem_dump_oversize_max = 0;
2235 2235  
2236 2236  static void
2237 2237  kmem_dumppr(char **pp, char *e, const char *format, ...)
2238 2238  {
2239 2239          char *p = *pp;
2240 2240  
2241 2241          if (p < e) {
2242 2242                  int n;
2243 2243                  va_list ap;
2244 2244  
2245 2245                  va_start(ap, format);
2246 2246                  n = vsnprintf(p, e - p, format, ap);
2247 2247                  va_end(ap);
2248 2248                  *pp = p + n;
2249 2249          }
2250 2250  }
2251 2251  
2252 2252  /*
2253 2253   * Called when dumpadm(8) configures dump parameters.
2254 2254   */
2255 2255  void
2256 2256  kmem_dump_init(size_t size)
2257 2257  {
2258 2258          /* Our caller ensures size is always set. */
2259 2259          ASSERT3U(size, >, 0);
2260 2260  
2261 2261          if (kmem_dump_start != NULL)
2262 2262                  kmem_free(kmem_dump_start, kmem_dump_size);
2263 2263  
2264 2264          kmem_dump_start = kmem_alloc(size, KM_SLEEP);
2265 2265          kmem_dump_size = size;
2266 2266          kmem_dump_curr = kmem_dump_start;
2267 2267          kmem_dump_end = (void *)((char *)kmem_dump_start + size);
2268 2268          copy_pattern(KMEM_UNINITIALIZED_PATTERN, kmem_dump_start, size);
2269 2269  }
2270 2270  
2271 2271  /*
2272 2272   * Set flag for each kmem_cache_t if is safe to use alternate dump
2273 2273   * memory. Called just before panic crash dump starts. Set the flag
2274 2274   * for the calling CPU.
2275 2275   */
2276 2276  void
2277 2277  kmem_dump_begin(void)
2278 2278  {
2279 2279          kmem_cache_t *cp;
2280 2280  
2281 2281          ASSERT(panicstr != NULL);
2282 2282  
2283 2283          for (cp = list_head(&kmem_caches); cp != NULL;
2284 2284              cp = list_next(&kmem_caches, cp)) {
2285 2285                  kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp);
2286 2286  
2287 2287                  if (cp->cache_arena->vm_cflags & VMC_DUMPSAFE) {
2288 2288                          cp->cache_flags |= KMF_DUMPDIVERT;
2289 2289                          ccp->cc_flags |= KMF_DUMPDIVERT;
2290 2290                          ccp->cc_dump_rounds = ccp->cc_rounds;
2291 2291                          ccp->cc_dump_prounds = ccp->cc_prounds;
2292 2292                          ccp->cc_rounds = ccp->cc_prounds = -1;
2293 2293                  } else {
2294 2294                          cp->cache_flags |= KMF_DUMPUNSAFE;
2295 2295                          ccp->cc_flags |= KMF_DUMPUNSAFE;
2296 2296                  }
2297 2297          }
2298 2298  }
2299 2299  
2300 2300  /*
2301 2301   * finished dump intercept
2302 2302   * print any warnings on the console
2303 2303   * return verbose information to dumpsys() in the given buffer
2304 2304   */
2305 2305  size_t
2306 2306  kmem_dump_finish(char *buf, size_t size)
2307 2307  {
2308 2308          int percent = 0;
2309 2309          size_t used;
2310 2310          char *e = buf + size;
2311 2311          char *p = buf;
2312 2312  
2313 2313          if (kmem_dump_curr == kmem_dump_end) {
2314 2314                  cmn_err(CE_WARN, "exceeded kmem_dump space of %lu "
2315 2315                      "bytes: kmem state in dump may be inconsistent",
2316 2316                      kmem_dump_size);
2317 2317          }
2318 2318  
2319 2319          if (kmem_dump_verbose == 0)
2320 2320                  return (0);
2321 2321  
2322 2322          used = (char *)kmem_dump_curr - (char *)kmem_dump_start;
2323 2323          percent = (used * 100) / kmem_dump_size;
2324 2324  
2325 2325          kmem_dumppr(&p, e, "%% heap used,%d\n", percent);
2326 2326          kmem_dumppr(&p, e, "used bytes,%ld\n", used);
2327 2327          kmem_dumppr(&p, e, "heap size,%ld\n", kmem_dump_size);
2328 2328          kmem_dumppr(&p, e, "Oversize allocs,%d\n",
2329 2329              kmem_dump_oversize_allocs);
2330 2330          kmem_dumppr(&p, e, "Oversize max size,%ld\n",
2331 2331              kmem_dump_oversize_max);
2332 2332  
2333 2333          /* return buffer size used */
2334 2334          if (p < e)
2335 2335                  bzero(p, e - p);
2336 2336          return (p - buf);
2337 2337  }
2338 2338  
2339 2339  /*
2340 2340   * Allocate a constructed object from alternate dump memory.
2341 2341   */
2342 2342  void *
2343 2343  kmem_cache_alloc_dump(kmem_cache_t *cp, int kmflag)
2344 2344  {
2345 2345          void *buf;
2346 2346          void *curr;
2347 2347          char *bufend;
2348 2348  
2349 2349          /* return a constructed object */
2350 2350          if ((buf = cp->cache_dump.kd_freelist) != NULL) {
2351 2351                  cp->cache_dump.kd_freelist = KMEM_DUMPCTL(cp, buf)->kdc_next;
2352 2352                  return (buf);
2353 2353          }
2354 2354  
2355 2355          /* create a new constructed object */
2356 2356          curr = kmem_dump_curr;
2357 2357          buf = (void *)P2ROUNDUP((uintptr_t)curr, cp->cache_align);
2358 2358          bufend = (char *)KMEM_DUMPCTL(cp, buf) + sizeof (kmem_dumpctl_t);
2359 2359  
2360 2360          /* hat layer objects cannot cross a page boundary */
2361 2361          if (cp->cache_align < PAGESIZE) {
2362 2362                  char *page = (char *)P2ROUNDUP((uintptr_t)buf, PAGESIZE);
2363 2363                  if (bufend > page) {
2364 2364                          bufend += page - (char *)buf;
2365 2365                          buf = (void *)page;
2366 2366                  }
2367 2367          }
2368 2368  
2369 2369          /* fall back to normal alloc if reserved area is used up */
2370 2370          if (bufend > (char *)kmem_dump_end) {
2371 2371                  kmem_dump_curr = kmem_dump_end;
2372 2372                  cp->cache_dump.kd_alloc_fails++;
2373 2373                  return (NULL);
2374 2374          }
2375 2375  
2376 2376          /*
2377 2377           * Must advance curr pointer before calling a constructor that
2378 2378           * may also allocate memory.
2379 2379           */
2380 2380          kmem_dump_curr = bufend;
2381 2381  
2382 2382          /* run constructor */
2383 2383          if (cp->cache_constructor != NULL &&
2384 2384              cp->cache_constructor(buf, cp->cache_private, kmflag)
2385 2385              != 0) {
2386 2386  #ifdef DEBUG
2387 2387                  printf("name='%s' cache=0x%p: kmem cache constructor failed\n",
2388 2388                      cp->cache_name, (void *)cp);
2389 2389  #endif
2390 2390                  /* reset curr pointer iff no allocs were done */
2391 2391                  if (kmem_dump_curr == bufend)
2392 2392                          kmem_dump_curr = curr;
2393 2393  
2394 2394                  cp->cache_dump.kd_alloc_fails++;
2395 2395                  /* fall back to normal alloc if the constructor fails */
2396 2396                  return (NULL);
2397 2397          }
2398 2398  
2399 2399          return (buf);
2400 2400  }
2401 2401  
2402 2402  /*
2403 2403   * Free a constructed object in alternate dump memory.
2404 2404   */
2405 2405  int
2406 2406  kmem_cache_free_dump(kmem_cache_t *cp, void *buf)
2407 2407  {
2408 2408          /* save constructed buffers for next time */
2409 2409          if ((char *)buf >= (char *)kmem_dump_start &&
2410 2410              (char *)buf < (char *)kmem_dump_end) {
2411 2411                  KMEM_DUMPCTL(cp, buf)->kdc_next = cp->cache_dump.kd_freelist;
2412 2412                  cp->cache_dump.kd_freelist = buf;
2413 2413                  return (0);
2414 2414          }
2415 2415  
2416 2416          /* just drop buffers that were allocated before dump started */
2417 2417          if (kmem_dump_curr < kmem_dump_end)
2418 2418                  return (0);
2419 2419  
2420 2420          /* fall back to normal free if reserved area is used up */
2421 2421          return (1);
2422 2422  }
2423 2423  
2424 2424  /*
2425 2425   * Allocate a constructed object from cache cp.
2426 2426   */
2427 2427  void *
2428 2428  kmem_cache_alloc(kmem_cache_t *cp, int kmflag)
2429 2429  {
2430 2430          kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp);
2431 2431          kmem_magazine_t *fmp;
2432 2432          void *buf;
2433 2433  
2434 2434          mutex_enter(&ccp->cc_lock);
2435 2435          for (;;) {
2436 2436                  /*
2437 2437                   * If there's an object available in the current CPU's
2438 2438                   * loaded magazine, just take it and return.
2439 2439                   */
2440 2440                  if (ccp->cc_rounds > 0) {
2441 2441                          buf = ccp->cc_loaded->mag_round[--ccp->cc_rounds];
2442 2442                          ccp->cc_alloc++;
2443 2443                          mutex_exit(&ccp->cc_lock);
2444 2444                          if (ccp->cc_flags & (KMF_BUFTAG | KMF_DUMPUNSAFE)) {
2445 2445                                  if (ccp->cc_flags & KMF_DUMPUNSAFE) {
2446 2446                                          ASSERT(!(ccp->cc_flags &
2447 2447                                              KMF_DUMPDIVERT));
2448 2448                                          cp->cache_dump.kd_unsafe++;
2449 2449                                  }
2450 2450                                  if ((ccp->cc_flags & KMF_BUFTAG) &&
2451 2451                                      kmem_cache_alloc_debug(cp, buf, kmflag, 0,
2452 2452                                      caller()) != 0) {
2453 2453                                          if (kmflag & KM_NOSLEEP)
2454 2454                                                  return (NULL);
2455 2455                                          mutex_enter(&ccp->cc_lock);
2456 2456                                          continue;
2457 2457                                  }
2458 2458                          }
2459 2459                          return (buf);
2460 2460                  }
2461 2461  
2462 2462                  /*
2463 2463                   * The loaded magazine is empty.  If the previously loaded
2464 2464                   * magazine was full, exchange them and try again.
2465 2465                   */
2466 2466                  if (ccp->cc_prounds > 0) {
2467 2467                          kmem_cpu_reload(ccp, ccp->cc_ploaded, ccp->cc_prounds);
2468 2468                          continue;
2469 2469                  }
2470 2470  
2471 2471                  /*
2472 2472                   * Return an alternate buffer at dump time to preserve
2473 2473                   * the heap.
2474 2474                   */
2475 2475                  if (ccp->cc_flags & (KMF_DUMPDIVERT | KMF_DUMPUNSAFE)) {
2476 2476                          if (ccp->cc_flags & KMF_DUMPUNSAFE) {
2477 2477                                  ASSERT(!(ccp->cc_flags & KMF_DUMPDIVERT));
2478 2478                                  /* log it so that we can warn about it */
2479 2479                                  cp->cache_dump.kd_unsafe++;
2480 2480                          } else {
2481 2481                                  if ((buf = kmem_cache_alloc_dump(cp, kmflag)) !=
2482 2482                                      NULL) {
2483 2483                                          mutex_exit(&ccp->cc_lock);
2484 2484                                          return (buf);
2485 2485                                  }
2486 2486                                  break;          /* fall back to slab layer */
2487 2487                          }
2488 2488                  }
2489 2489  
2490 2490                  /*
2491 2491                   * If the magazine layer is disabled, break out now.
2492 2492                   */
2493 2493                  if (ccp->cc_magsize == 0)
2494 2494                          break;
2495 2495  
2496 2496                  /*
2497 2497                   * Try to get a full magazine from the depot.
2498 2498                   */
2499 2499                  fmp = kmem_depot_alloc(cp, &cp->cache_full);
2500 2500                  if (fmp != NULL) {
2501 2501                          if (ccp->cc_ploaded != NULL)
2502 2502                                  kmem_depot_free(cp, &cp->cache_empty,
2503 2503                                      ccp->cc_ploaded);
2504 2504                          kmem_cpu_reload(ccp, fmp, ccp->cc_magsize);
2505 2505                          continue;
2506 2506                  }
2507 2507  
2508 2508                  /*
2509 2509                   * There are no full magazines in the depot,
2510 2510                   * so fall through to the slab layer.
2511 2511                   */
2512 2512                  break;
2513 2513          }
2514 2514          mutex_exit(&ccp->cc_lock);
2515 2515  
2516 2516          /*
2517 2517           * We couldn't allocate a constructed object from the magazine layer,
2518 2518           * so get a raw buffer from the slab layer and apply its constructor.
2519 2519           */
2520 2520          buf = kmem_slab_alloc(cp, kmflag);
2521 2521  
2522 2522          if (buf == NULL)
2523 2523                  return (NULL);
2524 2524  
2525 2525          if (cp->cache_flags & KMF_BUFTAG) {
2526 2526                  /*
2527 2527                   * Make kmem_cache_alloc_debug() apply the constructor for us.
2528 2528                   */
2529 2529                  int rc = kmem_cache_alloc_debug(cp, buf, kmflag, 1, caller());
2530 2530                  if (rc != 0) {
2531 2531                          if (kmflag & KM_NOSLEEP)
2532 2532                                  return (NULL);
2533 2533                          /*
2534 2534                           * kmem_cache_alloc_debug() detected corruption
2535 2535                           * but didn't panic (kmem_panic <= 0). We should not be
2536 2536                           * here because the constructor failed (indicated by a
2537 2537                           * return code of 1). Try again.
2538 2538                           */
2539 2539                          ASSERT(rc == -1);
2540 2540                          return (kmem_cache_alloc(cp, kmflag));
2541 2541                  }
2542 2542                  return (buf);
2543 2543          }
2544 2544  
2545 2545          if (cp->cache_constructor != NULL &&
2546 2546              cp->cache_constructor(buf, cp->cache_private, kmflag) != 0) {
2547 2547                  atomic_inc_64(&cp->cache_alloc_fail);
2548 2548                  kmem_slab_free(cp, buf);
2549 2549                  return (NULL);
2550 2550          }
2551 2551  
2552 2552          return (buf);
2553 2553  }
2554 2554  
2555 2555  /*
2556 2556   * The freed argument tells whether or not kmem_cache_free_debug() has already
2557 2557   * been called so that we can avoid the duplicate free error. For example, a
2558 2558   * buffer on a magazine has already been freed by the client but is still
2559 2559   * constructed.
2560 2560   */
2561 2561  static void
2562 2562  kmem_slab_free_constructed(kmem_cache_t *cp, void *buf, boolean_t freed)
2563 2563  {
2564 2564          if (!freed && (cp->cache_flags & KMF_BUFTAG))
2565 2565                  if (kmem_cache_free_debug(cp, buf, caller()) == -1)
2566 2566                          return;
2567 2567  
2568 2568          /*
2569 2569           * Note that if KMF_DEADBEEF is in effect and KMF_LITE is not,
2570 2570           * kmem_cache_free_debug() will have already applied the destructor.
2571 2571           */
2572 2572          if ((cp->cache_flags & (KMF_DEADBEEF | KMF_LITE)) != KMF_DEADBEEF &&
2573 2573              cp->cache_destructor != NULL) {
2574 2574                  if (cp->cache_flags & KMF_DEADBEEF) {   /* KMF_LITE implied */
2575 2575                          kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
2576 2576                          *(uint64_t *)buf = btp->bt_redzone;
2577 2577                          cp->cache_destructor(buf, cp->cache_private);
2578 2578                          *(uint64_t *)buf = KMEM_FREE_PATTERN;
2579 2579                  } else {
2580 2580                          cp->cache_destructor(buf, cp->cache_private);
2581 2581                  }
2582 2582          }
2583 2583  
2584 2584          kmem_slab_free(cp, buf);
2585 2585  }
2586 2586  
2587 2587  /*
2588 2588   * Used when there's no room to free a buffer to the per-CPU cache.
2589 2589   * Drops and re-acquires &ccp->cc_lock, and returns non-zero if the
2590 2590   * caller should try freeing to the per-CPU cache again.
2591 2591   * Note that we don't directly install the magazine in the cpu cache,
2592 2592   * since its state may have changed wildly while the lock was dropped.
2593 2593   */
2594 2594  static int
2595 2595  kmem_cpucache_magazine_alloc(kmem_cpu_cache_t *ccp, kmem_cache_t *cp)
2596 2596  {
2597 2597          kmem_magazine_t *emp;
2598 2598          kmem_magtype_t *mtp;
2599 2599  
2600 2600          ASSERT(MUTEX_HELD(&ccp->cc_lock));
2601 2601          ASSERT(((uint_t)ccp->cc_rounds == ccp->cc_magsize ||
2602 2602              ((uint_t)ccp->cc_rounds == -1)) &&
2603 2603              ((uint_t)ccp->cc_prounds == ccp->cc_magsize ||
2604 2604              ((uint_t)ccp->cc_prounds == -1)));
2605 2605  
2606 2606          emp = kmem_depot_alloc(cp, &cp->cache_empty);
2607 2607          if (emp != NULL) {
2608 2608                  if (ccp->cc_ploaded != NULL)
2609 2609                          kmem_depot_free(cp, &cp->cache_full,
2610 2610                              ccp->cc_ploaded);
2611 2611                  kmem_cpu_reload(ccp, emp, 0);
2612 2612                  return (1);
2613 2613          }
2614 2614          /*
2615 2615           * There are no empty magazines in the depot,
2616 2616           * so try to allocate a new one.  We must drop all locks
2617 2617           * across kmem_cache_alloc() because lower layers may
2618 2618           * attempt to allocate from this cache.
2619 2619           */
2620 2620          mtp = cp->cache_magtype;
2621 2621          mutex_exit(&ccp->cc_lock);
2622 2622          emp = kmem_cache_alloc(mtp->mt_cache, KM_NOSLEEP);
2623 2623          mutex_enter(&ccp->cc_lock);
2624 2624  
2625 2625          if (emp != NULL) {
2626 2626                  /*
2627 2627                   * We successfully allocated an empty magazine.
2628 2628                   * However, we had to drop ccp->cc_lock to do it,
2629 2629                   * so the cache's magazine size may have changed.
2630 2630                   * If so, free the magazine and try again.
2631 2631                   */
2632 2632                  if (ccp->cc_magsize != mtp->mt_magsize) {
2633 2633                          mutex_exit(&ccp->cc_lock);
2634 2634                          kmem_cache_free(mtp->mt_cache, emp);
2635 2635                          mutex_enter(&ccp->cc_lock);
2636 2636                          return (1);
2637 2637                  }
2638 2638  
2639 2639                  /*
2640 2640                   * We got a magazine of the right size.  Add it to
2641 2641                   * the depot and try the whole dance again.
2642 2642                   */
2643 2643                  kmem_depot_free(cp, &cp->cache_empty, emp);
2644 2644                  return (1);
2645 2645          }
2646 2646  
2647 2647          /*
2648 2648           * We couldn't allocate an empty magazine,
2649 2649           * so fall through to the slab layer.
2650 2650           */
2651 2651          return (0);
2652 2652  }
2653 2653  
2654 2654  /*
2655 2655   * Free a constructed object to cache cp.
2656 2656   */
2657 2657  void
2658 2658  kmem_cache_free(kmem_cache_t *cp, void *buf)
2659 2659  {
2660 2660          kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp);
2661 2661  
2662 2662          /*
2663 2663           * The client must not free either of the buffers passed to the move
2664 2664           * callback function.
2665 2665           */
2666 2666          ASSERT(cp->cache_defrag == NULL ||
2667 2667              cp->cache_defrag->kmd_thread != curthread ||
2668 2668              (buf != cp->cache_defrag->kmd_from_buf &&
2669 2669              buf != cp->cache_defrag->kmd_to_buf));
2670 2670  
2671 2671          if (ccp->cc_flags & (KMF_BUFTAG | KMF_DUMPDIVERT | KMF_DUMPUNSAFE)) {
2672 2672                  if (ccp->cc_flags & KMF_DUMPUNSAFE) {
2673 2673                          ASSERT(!(ccp->cc_flags & KMF_DUMPDIVERT));
2674 2674                          /* log it so that we can warn about it */
2675 2675                          cp->cache_dump.kd_unsafe++;
2676 2676                  } else if (KMEM_DUMPCC(ccp) && !kmem_cache_free_dump(cp, buf)) {
2677 2677                          return;
2678 2678                  }
2679 2679                  if (ccp->cc_flags & KMF_BUFTAG) {
2680 2680                          if (kmem_cache_free_debug(cp, buf, caller()) == -1)
2681 2681                                  return;
2682 2682                  }
2683 2683          }
2684 2684  
2685 2685          mutex_enter(&ccp->cc_lock);
2686 2686          /*
2687 2687           * Any changes to this logic should be reflected in kmem_slab_prefill()
2688 2688           */
2689 2689          for (;;) {
2690 2690                  /*
2691 2691                   * If there's a slot available in the current CPU's
2692 2692                   * loaded magazine, just put the object there and return.
2693 2693                   */
2694 2694                  if ((uint_t)ccp->cc_rounds < ccp->cc_magsize) {
2695 2695                          ccp->cc_loaded->mag_round[ccp->cc_rounds++] = buf;
2696 2696                          ccp->cc_free++;
2697 2697                          mutex_exit(&ccp->cc_lock);
2698 2698                          return;
2699 2699                  }
2700 2700  
2701 2701                  /*
2702 2702                   * The loaded magazine is full.  If the previously loaded
2703 2703                   * magazine was empty, exchange them and try again.
2704 2704                   */
2705 2705                  if (ccp->cc_prounds == 0) {
2706 2706                          kmem_cpu_reload(ccp, ccp->cc_ploaded, ccp->cc_prounds);
2707 2707                          continue;
2708 2708                  }
2709 2709  
2710 2710                  /*
2711 2711                   * If the magazine layer is disabled, break out now.
2712 2712                   */
2713 2713                  if (ccp->cc_magsize == 0)
2714 2714                          break;
2715 2715  
2716 2716                  if (!kmem_cpucache_magazine_alloc(ccp, cp)) {
2717 2717                          /*
2718 2718                           * We couldn't free our constructed object to the
2719 2719                           * magazine layer, so apply its destructor and free it
2720 2720                           * to the slab layer.
2721 2721                           */
2722 2722                          break;
2723 2723                  }
2724 2724          }
2725 2725          mutex_exit(&ccp->cc_lock);
2726 2726          kmem_slab_free_constructed(cp, buf, B_TRUE);
2727 2727  }
2728 2728  
2729 2729  static void
2730 2730  kmem_slab_prefill(kmem_cache_t *cp, kmem_slab_t *sp)
2731 2731  {
2732 2732          kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp);
2733 2733          int cache_flags = cp->cache_flags;
2734 2734  
2735 2735          kmem_bufctl_t *next, *head;
2736 2736          size_t nbufs;
2737 2737  
2738 2738          /*
2739 2739           * Completely allocate the newly created slab and put the pre-allocated
2740 2740           * buffers in magazines. Any of the buffers that cannot be put in
2741 2741           * magazines must be returned to the slab.
2742 2742           */
2743 2743          ASSERT(MUTEX_HELD(&cp->cache_lock));
2744 2744          ASSERT((cache_flags & (KMF_PREFILL|KMF_BUFTAG)) == KMF_PREFILL);
2745 2745          ASSERT(cp->cache_constructor == NULL);
2746 2746          ASSERT(sp->slab_cache == cp);
2747 2747          ASSERT(sp->slab_refcnt == 1);
2748 2748          ASSERT(sp->slab_head != NULL && sp->slab_chunks > sp->slab_refcnt);
2749 2749          ASSERT(avl_find(&cp->cache_partial_slabs, sp, NULL) == NULL);
2750 2750  
2751 2751          head = sp->slab_head;
2752 2752          nbufs = (sp->slab_chunks - sp->slab_refcnt);
2753 2753          sp->slab_head = NULL;
2754 2754          sp->slab_refcnt += nbufs;
2755 2755          cp->cache_bufslab -= nbufs;
2756 2756          cp->cache_slab_alloc += nbufs;
2757 2757          list_insert_head(&cp->cache_complete_slabs, sp);
2758 2758          cp->cache_complete_slab_count++;
2759 2759          mutex_exit(&cp->cache_lock);
2760 2760          mutex_enter(&ccp->cc_lock);
2761 2761  
2762 2762          while (head != NULL) {
2763 2763                  void *buf = KMEM_BUF(cp, head);
2764 2764                  /*
2765 2765                   * If there's a slot available in the current CPU's
2766 2766                   * loaded magazine, just put the object there and
2767 2767                   * continue.
2768 2768                   */
2769 2769                  if ((uint_t)ccp->cc_rounds < ccp->cc_magsize) {
2770 2770                          ccp->cc_loaded->mag_round[ccp->cc_rounds++] =
2771 2771                              buf;
2772 2772                          ccp->cc_free++;
2773 2773                          nbufs--;
2774 2774                          head = head->bc_next;
2775 2775                          continue;
2776 2776                  }
2777 2777  
2778 2778                  /*
2779 2779                   * The loaded magazine is full.  If the previously
2780 2780                   * loaded magazine was empty, exchange them and try
2781 2781                   * again.
2782 2782                   */
2783 2783                  if (ccp->cc_prounds == 0) {
2784 2784                          kmem_cpu_reload(ccp, ccp->cc_ploaded,
2785 2785                              ccp->cc_prounds);
2786 2786                          continue;
2787 2787                  }
2788 2788  
2789 2789                  /*
2790 2790                   * If the magazine layer is disabled, break out now.
2791 2791                   */
2792 2792  
2793 2793                  if (ccp->cc_magsize == 0) {
2794 2794                          break;
2795 2795                  }
2796 2796  
2797 2797                  if (!kmem_cpucache_magazine_alloc(ccp, cp))
2798 2798                          break;
2799 2799          }
2800 2800          mutex_exit(&ccp->cc_lock);
2801 2801          if (nbufs != 0) {
2802 2802                  ASSERT(head != NULL);
2803 2803  
2804 2804                  /*
2805 2805                   * If there was a failure, return remaining objects to
2806 2806                   * the slab
2807 2807                   */
2808 2808                  while (head != NULL) {
2809 2809                          ASSERT(nbufs != 0);
2810 2810                          next = head->bc_next;
2811 2811                          head->bc_next = NULL;
2812 2812                          kmem_slab_free(cp, KMEM_BUF(cp, head));
2813 2813                          head = next;
2814 2814                          nbufs--;
2815 2815                  }
2816 2816          }
2817 2817          ASSERT(head == NULL);
2818 2818          ASSERT(nbufs == 0);
2819 2819          mutex_enter(&cp->cache_lock);
2820 2820  }
2821 2821  
2822 2822  /*
2823 2823   * kmem_rezalloc() is currently considered private until we sort out how we want
2824 2824   * to handle realloc vs. reallocf style interfaces.
2825 2825   */
2826 2826  void *
2827 2827  kmem_rezalloc(void *oldbuf, size_t oldsize, size_t newsize, int kmflag)
2828 2828  {
2829 2829          void *newbuf = kmem_alloc(newsize, kmflag);
2830 2830          if (newbuf == NULL) {
2831 2831                  return (NULL);
2832 2832          }
2833 2833  
2834 2834          bcopy(oldbuf, newbuf, MIN(oldsize, newsize));
2835 2835          if (newsize > oldsize) {
2836 2836                  void *start = (void *)((uintptr_t)newbuf + oldsize);
2837 2837                  bzero(start, newsize - oldsize);
2838 2838          }
2839 2839  
2840 2840          if (oldbuf != NULL) {
2841 2841                  ASSERT3U(oldsize, !=, 0);
2842 2842                  kmem_free(oldbuf, oldsize);
2843 2843          }
2844 2844  
2845 2845          return (newbuf);
2846 2846  }
2847 2847  
2848 2848  void *
2849 2849  kmem_zalloc(size_t size, int kmflag)
2850 2850  {
2851 2851          size_t index;
2852 2852          void *buf;
2853 2853  
2854 2854          if ((index = ((size - 1) >> KMEM_ALIGN_SHIFT)) < KMEM_ALLOC_TABLE_MAX) {
2855 2855                  kmem_cache_t *cp = kmem_alloc_table[index];
2856 2856                  buf = kmem_cache_alloc(cp, kmflag);
2857 2857                  if (buf != NULL) {
2858 2858                          if ((cp->cache_flags & KMF_BUFTAG) && !KMEM_DUMP(cp)) {
2859 2859                                  kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
2860 2860                                  ((uint8_t *)buf)[size] = KMEM_REDZONE_BYTE;
2861 2861                                  ((uint32_t *)btp)[1] = KMEM_SIZE_ENCODE(size);
2862 2862  
2863 2863                                  if (cp->cache_flags & KMF_LITE) {
2864 2864                                          KMEM_BUFTAG_LITE_ENTER(btp,
2865 2865                                              kmem_lite_count, caller());
2866 2866                                  }
2867 2867                          }
2868 2868                          bzero(buf, size);
2869 2869                  }
2870 2870          } else {
2871 2871                  buf = kmem_alloc(size, kmflag);
2872 2872                  if (buf != NULL)
2873 2873                          bzero(buf, size);
2874 2874          }
2875 2875          return (buf);
2876 2876  }
2877 2877  
2878 2878  void *
2879 2879  kmem_alloc(size_t size, int kmflag)
2880 2880  {
2881 2881          size_t index;
2882 2882          kmem_cache_t *cp;
2883 2883          void *buf;
2884 2884  
2885 2885          if ((index = ((size - 1) >> KMEM_ALIGN_SHIFT)) < KMEM_ALLOC_TABLE_MAX) {
2886 2886                  cp = kmem_alloc_table[index];
2887 2887                  /* fall through to kmem_cache_alloc() */
2888 2888  
2889 2889          } else if ((index = ((size - 1) >> KMEM_BIG_SHIFT)) <
2890 2890              kmem_big_alloc_table_max) {
2891 2891                  cp = kmem_big_alloc_table[index];
2892 2892                  /* fall through to kmem_cache_alloc() */
2893 2893  
2894 2894          } else {
2895 2895                  if (size == 0) {
2896 2896                          if (kmflag != KM_SLEEP && !(kmflag & KM_PANIC))
2897 2897                                  return (NULL);
2898 2898  
2899 2899                          /*
2900 2900                           * If this is a sleeping allocation or one that has
2901 2901                           * been specified to panic on allocation failure, we
2902 2902                           * consider it to be deprecated behavior to allocate
2903 2903                           * 0 bytes.  If we have been configured to panic under
2904 2904                           * this condition, we panic; if to warn, we warn -- and
2905 2905                           * regardless, we log to the kmem_zerosized_log that
2906 2906                           * that this condition has occurred (which gives us
2907 2907                           * enough information to be able to debug it).
2908 2908                           */
2909 2909                          if (kmem_panic && kmem_panic_zerosized)
2910 2910                                  panic("attempted to kmem_alloc() size of 0");
2911 2911  
2912 2912                          if (kmem_warn_zerosized) {
2913 2913                                  cmn_err(CE_WARN, "kmem_alloc(): sleeping "
2914 2914                                      "allocation with size of 0; "
2915 2915                                      "see kmem_zerosized_log for details");
2916 2916                          }
2917 2917  
2918 2918                          kmem_log_event(kmem_zerosized_log, NULL, NULL, NULL);
2919 2919  
2920 2920                          return (NULL);
2921 2921                  }
2922 2922  
2923 2923                  buf = vmem_alloc(kmem_oversize_arena, size,
2924 2924                      kmflag & KM_VMFLAGS);
2925 2925                  if (buf == NULL)
2926 2926                          kmem_log_event(kmem_failure_log, NULL, NULL,
2927 2927                              (void *)size);
2928 2928                  else if (KMEM_DUMP(kmem_slab_cache)) {
2929 2929                          /* stats for dump intercept */
2930 2930                          kmem_dump_oversize_allocs++;
2931 2931                          if (size > kmem_dump_oversize_max)
2932 2932                                  kmem_dump_oversize_max = size;
2933 2933                  }
2934 2934                  return (buf);
2935 2935          }
2936 2936  
2937 2937          buf = kmem_cache_alloc(cp, kmflag);
2938 2938          if ((cp->cache_flags & KMF_BUFTAG) && !KMEM_DUMP(cp) && buf != NULL) {
2939 2939                  kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
2940 2940                  ((uint8_t *)buf)[size] = KMEM_REDZONE_BYTE;
2941 2941                  ((uint32_t *)btp)[1] = KMEM_SIZE_ENCODE(size);
2942 2942  
2943 2943                  if (cp->cache_flags & KMF_LITE) {
2944 2944                          KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, caller());
2945 2945                  }
2946 2946          }
2947 2947          return (buf);
2948 2948  }
2949 2949  
2950 2950  void
2951 2951  kmem_free(void *buf, size_t size)
2952 2952  {
2953 2953          size_t index;
2954 2954          kmem_cache_t *cp;
2955 2955  
2956 2956          if ((index = (size - 1) >> KMEM_ALIGN_SHIFT) < KMEM_ALLOC_TABLE_MAX) {
2957 2957                  cp = kmem_alloc_table[index];
2958 2958                  /* fall through to kmem_cache_free() */
2959 2959  
2960 2960          } else if ((index = ((size - 1) >> KMEM_BIG_SHIFT)) <
2961 2961              kmem_big_alloc_table_max) {
2962 2962                  cp = kmem_big_alloc_table[index];
2963 2963                  /* fall through to kmem_cache_free() */
2964 2964  
2965 2965          } else {
2966 2966                  EQUIV(buf == NULL, size == 0);
2967 2967                  if (buf == NULL && size == 0)
2968 2968                          return;
2969 2969                  vmem_free(kmem_oversize_arena, buf, size);
2970 2970                  return;
2971 2971          }
2972 2972  
2973 2973          if ((cp->cache_flags & KMF_BUFTAG) && !KMEM_DUMP(cp)) {
2974 2974                  kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf);
2975 2975                  uint32_t *ip = (uint32_t *)btp;
2976 2976                  if (ip[1] != KMEM_SIZE_ENCODE(size)) {
2977 2977                          if (*(uint64_t *)buf == KMEM_FREE_PATTERN) {
2978 2978                                  kmem_error(KMERR_DUPFREE, cp, buf);
2979 2979                                  return;
2980 2980                          }
2981 2981                          if (KMEM_SIZE_VALID(ip[1])) {
2982 2982                                  ip[0] = KMEM_SIZE_ENCODE(size);
2983 2983                                  kmem_error(KMERR_BADSIZE, cp, buf);
2984 2984                          } else {
2985 2985                                  kmem_error(KMERR_REDZONE, cp, buf);
2986 2986                          }
2987 2987                          return;
2988 2988                  }
2989 2989                  if (((uint8_t *)buf)[size] != KMEM_REDZONE_BYTE) {
2990 2990                          kmem_error(KMERR_REDZONE, cp, buf);
2991 2991                          return;
2992 2992                  }
2993 2993                  btp->bt_redzone = KMEM_REDZONE_PATTERN;
2994 2994                  if (cp->cache_flags & KMF_LITE) {
2995 2995                          KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count,
2996 2996                              caller());
2997 2997                  }
2998 2998          }
2999 2999          kmem_cache_free(cp, buf);
3000 3000  }
3001 3001  
3002 3002  void *
3003 3003  kmem_firewall_va_alloc(vmem_t *vmp, size_t size, int vmflag)
3004 3004  {
3005 3005          size_t realsize = size + vmp->vm_quantum;
3006 3006          void *addr;
3007 3007  
3008 3008          /*
3009 3009           * Annoying edge case: if 'size' is just shy of ULONG_MAX, adding
3010 3010           * vm_quantum will cause integer wraparound.  Check for this, and
3011 3011           * blow off the firewall page in this case.  Note that such a
3012 3012           * giant allocation (the entire kernel address space) can never
3013 3013           * be satisfied, so it will either fail immediately (VM_NOSLEEP)
3014 3014           * or sleep forever (VM_SLEEP).  Thus, there is no need for a
3015 3015           * corresponding check in kmem_firewall_va_free().
3016 3016           */
3017 3017          if (realsize < size)
3018 3018                  realsize = size;
3019 3019  
3020 3020          /*
3021 3021           * While boot still owns resource management, make sure that this
3022 3022           * redzone virtual address allocation is properly accounted for in
3023 3023           * OBPs "virtual-memory" "available" lists because we're
3024 3024           * effectively claiming them for a red zone.  If we don't do this,
3025 3025           * the available lists become too fragmented and too large for the
3026 3026           * current boot/kernel memory list interface.
3027 3027           */
3028 3028          addr = vmem_alloc(vmp, realsize, vmflag | VM_NEXTFIT);
3029 3029  
3030 3030          if (addr != NULL && kvseg.s_base == NULL && realsize != size)
3031 3031                  (void) boot_virt_alloc((char *)addr + size, vmp->vm_quantum);
3032 3032  
3033 3033          return (addr);
3034 3034  }
3035 3035  
3036 3036  void
3037 3037  kmem_firewall_va_free(vmem_t *vmp, void *addr, size_t size)
3038 3038  {
3039 3039          ASSERT((kvseg.s_base == NULL ?
3040 3040              va_to_pfn((char *)addr + size) :
3041 3041              hat_getpfnum(kas.a_hat, (caddr_t)addr + size)) == PFN_INVALID);
3042 3042  
3043 3043          vmem_free(vmp, addr, size + vmp->vm_quantum);
3044 3044  }
3045 3045  
3046 3046  /*
3047 3047   * Try to allocate at least `size' bytes of memory without sleeping or
3048 3048   * panicking. Return actual allocated size in `asize'. If allocation failed,
3049 3049   * try final allocation with sleep or panic allowed.
3050 3050   */
3051 3051  void *
3052 3052  kmem_alloc_tryhard(size_t size, size_t *asize, int kmflag)
3053 3053  {
3054 3054          void *p;
3055 3055  
3056 3056          *asize = P2ROUNDUP(size, KMEM_ALIGN);
3057 3057          do {
3058 3058                  p = kmem_alloc(*asize, (kmflag | KM_NOSLEEP) & ~KM_PANIC);
3059 3059                  if (p != NULL)
3060 3060                          return (p);
3061 3061                  *asize += KMEM_ALIGN;
3062 3062          } while (*asize <= PAGESIZE);
3063 3063  
3064 3064          *asize = P2ROUNDUP(size, KMEM_ALIGN);
3065 3065          return (kmem_alloc(*asize, kmflag));
3066 3066  }
3067 3067  
3068 3068  /*
3069 3069   * Reclaim all unused memory from a cache.
3070 3070   */
3071 3071  static void
3072 3072  kmem_cache_reap(kmem_cache_t *cp)
3073 3073  {
3074 3074          ASSERT(taskq_member(kmem_taskq, curthread));
3075 3075          cp->cache_reap++;
3076 3076  
3077 3077          /*
3078 3078           * Ask the cache's owner to free some memory if possible.
3079 3079           * The idea is to handle things like the inode cache, which
3080 3080           * typically sits on a bunch of memory that it doesn't truly
3081 3081           * *need*.  Reclaim policy is entirely up to the owner; this
3082 3082           * callback is just an advisory plea for help.
3083 3083           */
3084 3084          if (cp->cache_reclaim != NULL) {
3085 3085                  long delta;
3086 3086  
3087 3087                  /*
3088 3088                   * Reclaimed memory should be reapable (not included in the
3089 3089                   * depot's working set).
3090 3090                   */
3091 3091                  delta = cp->cache_full.ml_total;
3092 3092                  cp->cache_reclaim(cp->cache_private);
3093 3093                  delta = cp->cache_full.ml_total - delta;
3094 3094                  if (delta > 0) {
3095 3095                          mutex_enter(&cp->cache_depot_lock);
3096 3096                          cp->cache_full.ml_reaplimit += delta;
3097 3097                          cp->cache_full.ml_min += delta;
3098 3098                          mutex_exit(&cp->cache_depot_lock);
3099 3099                  }
3100 3100          }
3101 3101  
3102 3102          kmem_depot_ws_reap(cp);
3103 3103  
3104 3104          if (cp->cache_defrag != NULL && !kmem_move_noreap) {
3105 3105                  kmem_cache_defrag(cp);
3106 3106          }
3107 3107  }
3108 3108  
3109 3109  static void
3110 3110  kmem_reap_timeout(void *flag_arg)
3111 3111  {
3112 3112          uint32_t *flag = (uint32_t *)flag_arg;
3113 3113  
3114 3114          ASSERT(flag == &kmem_reaping || flag == &kmem_reaping_idspace);
3115 3115          *flag = 0;
3116 3116  }
3117 3117  
3118 3118  static void
3119 3119  kmem_reap_done(void *flag)
3120 3120  {
3121 3121          if (!callout_init_done) {
3122 3122                  /* can't schedule a timeout at this point */
3123 3123                  kmem_reap_timeout(flag);
3124 3124          } else {
3125 3125                  (void) timeout(kmem_reap_timeout, flag, kmem_reap_interval);
3126 3126          }
3127 3127  }
3128 3128  
3129 3129  static void
3130 3130  kmem_reap_start(void *flag)
3131 3131  {
3132 3132          ASSERT(flag == &kmem_reaping || flag == &kmem_reaping_idspace);
3133 3133  
3134 3134          if (flag == &kmem_reaping) {
3135 3135                  kmem_cache_applyall(kmem_cache_reap, kmem_taskq, TQ_NOSLEEP);
3136 3136                  /*
3137 3137                   * if we have segkp under heap, reap segkp cache.
3138 3138                   */
3139 3139                  if (segkp_fromheap)
3140 3140                          segkp_cache_free();
3141 3141          }
3142 3142          else
3143 3143                  kmem_cache_applyall_id(kmem_cache_reap, kmem_taskq, TQ_NOSLEEP);
3144 3144  
3145 3145          /*
3146 3146           * We use taskq_dispatch() to schedule a timeout to clear
3147 3147           * the flag so that kmem_reap() becomes self-throttling:
3148 3148           * we won't reap again until the current reap completes *and*
3149 3149           * at least kmem_reap_interval ticks have elapsed.
3150 3150           */
3151 3151          if (taskq_dispatch(kmem_taskq, kmem_reap_done, flag, TQ_NOSLEEP) ==
3152 3152              TASKQID_INVALID)
3153 3153                  kmem_reap_done(flag);
3154 3154  }
3155 3155  
3156 3156  static void
3157 3157  kmem_reap_common(void *flag_arg)
3158 3158  {
3159 3159          uint32_t *flag = (uint32_t *)flag_arg;
3160 3160  
3161 3161          if (MUTEX_HELD(&kmem_cache_lock) || kmem_taskq == NULL ||
3162 3162              atomic_cas_32(flag, 0, 1) != 0)
3163 3163                  return;
3164 3164  
3165 3165          /*
3166 3166           * It may not be kosher to do memory allocation when a reap is called
3167 3167           * (for example, if vmem_populate() is in the call chain).  So we
3168 3168           * start the reap going with a TQ_NOALLOC dispatch.  If the dispatch
3169 3169           * fails, we reset the flag, and the next reap will try again.
3170 3170           */
3171 3171          if (taskq_dispatch(kmem_taskq, kmem_reap_start, flag, TQ_NOALLOC) ==
3172 3172              TASKQID_INVALID)
3173 3173                  *flag = 0;
3174 3174  }
3175 3175  
3176 3176  /*
3177 3177   * Reclaim all unused memory from all caches.  Called from the VM system
3178 3178   * when memory gets tight.
3179 3179   */
3180 3180  void
3181 3181  kmem_reap(void)
3182 3182  {
3183 3183          kmem_reap_common(&kmem_reaping);
3184 3184  }
3185 3185  
3186 3186  /*
3187 3187   * Reclaim all unused memory from identifier arenas, called when a vmem
3188 3188   * arena not back by memory is exhausted.  Since reaping memory-backed caches
3189 3189   * cannot help with identifier exhaustion, we avoid both a large amount of
3190 3190   * work and unwanted side-effects from reclaim callbacks.
3191 3191   */
3192 3192  void
3193 3193  kmem_reap_idspace(void)
3194 3194  {
3195 3195          kmem_reap_common(&kmem_reaping_idspace);
3196 3196  }
3197 3197  
3198 3198  /*
3199 3199   * Purge all magazines from a cache and set its magazine limit to zero.
3200 3200   * All calls are serialized by the kmem_taskq lock, except for the final
3201 3201   * call from kmem_cache_destroy().
3202 3202   */
3203 3203  static void
3204 3204  kmem_cache_magazine_purge(kmem_cache_t *cp)
3205 3205  {
3206 3206          kmem_cpu_cache_t *ccp;
3207 3207          kmem_magazine_t *mp, *pmp;
3208 3208          int rounds, prounds, cpu_seqid;
3209 3209  
3210 3210          ASSERT(!list_link_active(&cp->cache_link) ||
3211 3211              taskq_member(kmem_taskq, curthread));
3212 3212          ASSERT(MUTEX_NOT_HELD(&cp->cache_lock));
3213 3213  
3214 3214          for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) {
3215 3215                  ccp = &cp->cache_cpu[cpu_seqid];
3216 3216  
3217 3217                  mutex_enter(&ccp->cc_lock);
3218 3218                  mp = ccp->cc_loaded;
3219 3219                  pmp = ccp->cc_ploaded;
3220 3220                  rounds = ccp->cc_rounds;
3221 3221                  prounds = ccp->cc_prounds;
3222 3222                  ccp->cc_loaded = NULL;
3223 3223                  ccp->cc_ploaded = NULL;
3224 3224                  ccp->cc_rounds = -1;
3225 3225                  ccp->cc_prounds = -1;
3226 3226                  ccp->cc_magsize = 0;
3227 3227                  mutex_exit(&ccp->cc_lock);
3228 3228  
3229 3229                  if (mp)
3230 3230                          kmem_magazine_destroy(cp, mp, rounds);
3231 3231                  if (pmp)
3232 3232                          kmem_magazine_destroy(cp, pmp, prounds);
3233 3233          }
3234 3234  
3235 3235          kmem_depot_ws_zero(cp);
3236 3236          kmem_depot_ws_reap(cp);
3237 3237  }
3238 3238  
3239 3239  /*
3240 3240   * Enable per-cpu magazines on a cache.
3241 3241   */
3242 3242  static void
3243 3243  kmem_cache_magazine_enable(kmem_cache_t *cp)
3244 3244  {
3245 3245          int cpu_seqid;
3246 3246  
3247 3247          if (cp->cache_flags & KMF_NOMAGAZINE)
3248 3248                  return;
3249 3249  
3250 3250          for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) {
3251 3251                  kmem_cpu_cache_t *ccp = &cp->cache_cpu[cpu_seqid];
3252 3252                  mutex_enter(&ccp->cc_lock);
3253 3253                  ccp->cc_magsize = cp->cache_magtype->mt_magsize;
3254 3254                  mutex_exit(&ccp->cc_lock);
3255 3255          }
3256 3256  
3257 3257  }
3258 3258  
3259 3259  /*
3260 3260   * Allow our caller to determine if there are running reaps.
3261 3261   *
3262 3262   * This call is very conservative and may return B_TRUE even when
3263 3263   * reaping activity isn't active. If it returns B_FALSE, then reaping
3264 3264   * activity is definitely inactive.
3265 3265   */
3266 3266  boolean_t
3267 3267  kmem_cache_reap_active(void)
3268 3268  {
3269 3269          return (!taskq_empty(kmem_taskq));
3270 3270  }
3271 3271  
3272 3272  /*
3273 3273   * Reap (almost) everything soon.
3274 3274   *
3275 3275   * Note: this does not wait for the reap-tasks to complete. Caller
3276 3276   * should use kmem_cache_reap_active() (above) and/or moderation to
3277 3277   * avoid scheduling too many reap-tasks.
3278 3278   */
3279 3279  void
3280 3280  kmem_cache_reap_soon(kmem_cache_t *cp)
3281 3281  {
3282 3282          ASSERT(list_link_active(&cp->cache_link));
3283 3283  
3284 3284          kmem_depot_ws_zero(cp);
3285 3285  
3286 3286          (void) taskq_dispatch(kmem_taskq,
3287 3287              (task_func_t *)kmem_depot_ws_reap, cp, TQ_SLEEP);
3288 3288  }
3289 3289  
3290 3290  /*
3291 3291   * Recompute a cache's magazine size.  The trade-off is that larger magazines
3292 3292   * provide a higher transfer rate with the depot, while smaller magazines
3293 3293   * reduce memory consumption.  Magazine resizing is an expensive operation;
3294 3294   * it should not be done frequently.
3295 3295   *
3296 3296   * Changes to the magazine size are serialized by the kmem_taskq lock.
3297 3297   *
3298 3298   * Note: at present this only grows the magazine size.  It might be useful
3299 3299   * to allow shrinkage too.
3300 3300   */
3301 3301  static void
3302 3302  kmem_cache_magazine_resize(kmem_cache_t *cp)
3303 3303  {
3304 3304          kmem_magtype_t *mtp = cp->cache_magtype;
3305 3305  
3306 3306          ASSERT(taskq_member(kmem_taskq, curthread));
3307 3307  
3308 3308          if (cp->cache_chunksize < mtp->mt_maxbuf) {
3309 3309                  kmem_cache_magazine_purge(cp);
3310 3310                  mutex_enter(&cp->cache_depot_lock);
3311 3311                  cp->cache_magtype = ++mtp;
3312 3312                  cp->cache_depot_contention_prev =
3313 3313                      cp->cache_depot_contention + INT_MAX;
3314 3314                  mutex_exit(&cp->cache_depot_lock);
3315 3315                  kmem_cache_magazine_enable(cp);
3316 3316          }
3317 3317  }
3318 3318  
3319 3319  /*
3320 3320   * Rescale a cache's hash table, so that the table size is roughly the
3321 3321   * cache size.  We want the average lookup time to be extremely small.
3322 3322   */
3323 3323  static void
3324 3324  kmem_hash_rescale(kmem_cache_t *cp)
3325 3325  {
3326 3326          kmem_bufctl_t **old_table, **new_table, *bcp;
3327 3327          size_t old_size, new_size, h;
3328 3328  
3329 3329          ASSERT(taskq_member(kmem_taskq, curthread));
3330 3330  
3331 3331          new_size = MAX(KMEM_HASH_INITIAL,
3332 3332              1 << (highbit(3 * cp->cache_buftotal + 4) - 2));
3333 3333          old_size = cp->cache_hash_mask + 1;
3334 3334  
3335 3335          if ((old_size >> 1) <= new_size && new_size <= (old_size << 1))
3336 3336                  return;
3337 3337  
3338 3338          new_table = vmem_alloc(kmem_hash_arena, new_size * sizeof (void *),
3339 3339              VM_NOSLEEP);
3340 3340          if (new_table == NULL)
3341 3341                  return;
3342 3342          bzero(new_table, new_size * sizeof (void *));
3343 3343  
3344 3344          mutex_enter(&cp->cache_lock);
3345 3345  
3346 3346          old_size = cp->cache_hash_mask + 1;
3347 3347          old_table = cp->cache_hash_table;
3348 3348  
3349 3349          cp->cache_hash_mask = new_size - 1;
3350 3350          cp->cache_hash_table = new_table;
3351 3351          cp->cache_rescale++;
3352 3352  
3353 3353          for (h = 0; h < old_size; h++) {
3354 3354                  bcp = old_table[h];
3355 3355                  while (bcp != NULL) {
3356 3356                          void *addr = bcp->bc_addr;
3357 3357                          kmem_bufctl_t *next_bcp = bcp->bc_next;
3358 3358                          kmem_bufctl_t **hash_bucket = KMEM_HASH(cp, addr);
3359 3359                          bcp->bc_next = *hash_bucket;
3360 3360                          *hash_bucket = bcp;
3361 3361                          bcp = next_bcp;
3362 3362                  }
3363 3363          }
3364 3364  
3365 3365          mutex_exit(&cp->cache_lock);
3366 3366  
3367 3367          vmem_free(kmem_hash_arena, old_table, old_size * sizeof (void *));
3368 3368  }
3369 3369  
3370 3370  /*
3371 3371   * Perform periodic maintenance on a cache: hash rescaling, depot working-set
3372 3372   * update, magazine resizing, and slab consolidation.
3373 3373   */
3374 3374  static void
3375 3375  kmem_cache_update(kmem_cache_t *cp)
3376 3376  {
3377 3377          int need_hash_rescale = 0;
3378 3378          int need_magazine_resize = 0;
3379 3379  
3380 3380          ASSERT(MUTEX_HELD(&kmem_cache_lock));
3381 3381  
3382 3382          /*
3383 3383           * If the cache has become much larger or smaller than its hash table,
3384 3384           * fire off a request to rescale the hash table.
3385 3385           */
3386 3386          mutex_enter(&cp->cache_lock);
3387 3387  
3388 3388          if ((cp->cache_flags & KMF_HASH) &&
3389 3389              (cp->cache_buftotal > (cp->cache_hash_mask << 1) ||
3390 3390              (cp->cache_buftotal < (cp->cache_hash_mask >> 1) &&
3391 3391              cp->cache_hash_mask > KMEM_HASH_INITIAL)))
3392 3392                  need_hash_rescale = 1;
3393 3393  
3394 3394          mutex_exit(&cp->cache_lock);
3395 3395  
3396 3396          /*
3397 3397           * Update the depot working set statistics.
3398 3398           */
3399 3399          kmem_depot_ws_update(cp);
3400 3400  
3401 3401          /*
3402 3402           * If there's a lot of contention in the depot,
3403 3403           * increase the magazine size.
3404 3404           */
3405 3405          mutex_enter(&cp->cache_depot_lock);
3406 3406  
3407 3407          if (cp->cache_chunksize < cp->cache_magtype->mt_maxbuf &&
3408 3408              (int)(cp->cache_depot_contention -
3409 3409              cp->cache_depot_contention_prev) > kmem_depot_contention)
3410 3410                  need_magazine_resize = 1;
3411 3411  
3412 3412          cp->cache_depot_contention_prev = cp->cache_depot_contention;
3413 3413  
3414 3414          mutex_exit(&cp->cache_depot_lock);
3415 3415  
3416 3416          if (need_hash_rescale)
3417 3417                  (void) taskq_dispatch(kmem_taskq,
3418 3418                      (task_func_t *)kmem_hash_rescale, cp, TQ_NOSLEEP);
3419 3419  
3420 3420          if (need_magazine_resize)
3421 3421                  (void) taskq_dispatch(kmem_taskq,
3422 3422                      (task_func_t *)kmem_cache_magazine_resize, cp, TQ_NOSLEEP);
3423 3423  
3424 3424          if (cp->cache_defrag != NULL)
3425 3425                  (void) taskq_dispatch(kmem_taskq,
3426 3426                      (task_func_t *)kmem_cache_scan, cp, TQ_NOSLEEP);
3427 3427  }
3428 3428  
3429 3429  static void kmem_update(void *);
3430 3430  
3431 3431  static void
3432 3432  kmem_update_timeout(void *dummy)
3433 3433  {
3434 3434          (void) timeout(kmem_update, dummy, kmem_reap_interval);
3435 3435  }
3436 3436  
3437 3437  static void
3438 3438  kmem_update(void *dummy)
3439 3439  {
3440 3440          kmem_cache_applyall(kmem_cache_update, NULL, TQ_NOSLEEP);
3441 3441  
3442 3442          /*
3443 3443           * We use taskq_dispatch() to reschedule the timeout so that
3444 3444           * kmem_update() becomes self-throttling: it won't schedule
3445 3445           * new tasks until all previous tasks have completed.
3446 3446           */
3447 3447          if (taskq_dispatch(kmem_taskq, kmem_update_timeout, dummy, TQ_NOSLEEP)
3448 3448              == TASKQID_INVALID)
3449 3449                  kmem_update_timeout(NULL);
3450 3450  }
3451 3451  
3452 3452  static int
3453 3453  kmem_cache_kstat_update(kstat_t *ksp, int rw)
3454 3454  {
3455 3455          struct kmem_cache_kstat *kmcp = &kmem_cache_kstat;
3456 3456          kmem_cache_t *cp = ksp->ks_private;
3457 3457          uint64_t cpu_buf_avail;
3458 3458          uint64_t buf_avail = 0;
3459 3459          int cpu_seqid;
3460 3460          long reap;
3461 3461  
3462 3462          ASSERT(MUTEX_HELD(&kmem_cache_kstat_lock));
3463 3463  
3464 3464          if (rw == KSTAT_WRITE)
3465 3465                  return (EACCES);
3466 3466  
3467 3467          mutex_enter(&cp->cache_lock);
3468 3468  
3469 3469          kmcp->kmc_alloc_fail.value.ui64         = cp->cache_alloc_fail;
3470 3470          kmcp->kmc_alloc.value.ui64              = cp->cache_slab_alloc;
3471 3471          kmcp->kmc_free.value.ui64               = cp->cache_slab_free;
3472 3472          kmcp->kmc_slab_alloc.value.ui64         = cp->cache_slab_alloc;
3473 3473          kmcp->kmc_slab_free.value.ui64          = cp->cache_slab_free;
3474 3474  
3475 3475          for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) {
3476 3476                  kmem_cpu_cache_t *ccp = &cp->cache_cpu[cpu_seqid];
3477 3477  
3478 3478                  mutex_enter(&ccp->cc_lock);
3479 3479  
3480 3480                  cpu_buf_avail = 0;
3481 3481                  if (ccp->cc_rounds > 0)
3482 3482                          cpu_buf_avail += ccp->cc_rounds;
3483 3483                  if (ccp->cc_prounds > 0)
3484 3484                          cpu_buf_avail += ccp->cc_prounds;
3485 3485  
3486 3486                  kmcp->kmc_alloc.value.ui64      += ccp->cc_alloc;
3487 3487                  kmcp->kmc_free.value.ui64       += ccp->cc_free;
3488 3488                  buf_avail                       += cpu_buf_avail;
3489 3489  
3490 3490                  mutex_exit(&ccp->cc_lock);
3491 3491          }
3492 3492  
3493 3493          mutex_enter(&cp->cache_depot_lock);
3494 3494  
3495 3495          kmcp->kmc_depot_alloc.value.ui64        = cp->cache_full.ml_alloc;
3496 3496          kmcp->kmc_depot_free.value.ui64         = cp->cache_empty.ml_alloc;
3497 3497          kmcp->kmc_depot_contention.value.ui64   = cp->cache_depot_contention;
3498 3498          kmcp->kmc_full_magazines.value.ui64     = cp->cache_full.ml_total;
3499 3499          kmcp->kmc_empty_magazines.value.ui64    = cp->cache_empty.ml_total;
3500 3500          kmcp->kmc_magazine_size.value.ui64      =
3501 3501              (cp->cache_flags & KMF_NOMAGAZINE) ?
3502 3502              0 : cp->cache_magtype->mt_magsize;
3503 3503  
3504 3504          kmcp->kmc_alloc.value.ui64              += cp->cache_full.ml_alloc;
3505 3505          kmcp->kmc_free.value.ui64               += cp->cache_empty.ml_alloc;
3506 3506          buf_avail += cp->cache_full.ml_total * cp->cache_magtype->mt_magsize;
3507 3507  
3508 3508          reap = MIN(cp->cache_full.ml_reaplimit, cp->cache_full.ml_min);
3509 3509          reap = MIN(reap, cp->cache_full.ml_total);
3510 3510  
3511 3511          mutex_exit(&cp->cache_depot_lock);
3512 3512  
3513 3513          kmcp->kmc_buf_size.value.ui64   = cp->cache_bufsize;
3514 3514          kmcp->kmc_align.value.ui64      = cp->cache_align;
3515 3515          kmcp->kmc_chunk_size.value.ui64 = cp->cache_chunksize;
3516 3516          kmcp->kmc_slab_size.value.ui64  = cp->cache_slabsize;
3517 3517          kmcp->kmc_buf_constructed.value.ui64 = buf_avail;
3518 3518          buf_avail += cp->cache_bufslab;
3519 3519          kmcp->kmc_buf_avail.value.ui64  = buf_avail;
3520 3520          kmcp->kmc_buf_inuse.value.ui64  = cp->cache_buftotal - buf_avail;
3521 3521          kmcp->kmc_buf_total.value.ui64  = cp->cache_buftotal;
3522 3522          kmcp->kmc_buf_max.value.ui64    = cp->cache_bufmax;
3523 3523          kmcp->kmc_slab_create.value.ui64        = cp->cache_slab_create;
3524 3524          kmcp->kmc_slab_destroy.value.ui64       = cp->cache_slab_destroy;
3525 3525          kmcp->kmc_hash_size.value.ui64  = (cp->cache_flags & KMF_HASH) ?
3526 3526              cp->cache_hash_mask + 1 : 0;
3527 3527          kmcp->kmc_hash_lookup_depth.value.ui64  = cp->cache_lookup_depth;
3528 3528          kmcp->kmc_hash_rescale.value.ui64       = cp->cache_rescale;
3529 3529          kmcp->kmc_vmem_source.value.ui64        = cp->cache_arena->vm_id;
3530 3530          kmcp->kmc_reap.value.ui64       = cp->cache_reap;
3531 3531  
3532 3532          if (cp->cache_defrag == NULL) {
3533 3533                  kmcp->kmc_move_callbacks.value.ui64     = 0;
3534 3534                  kmcp->kmc_move_yes.value.ui64           = 0;
3535 3535                  kmcp->kmc_move_no.value.ui64            = 0;
3536 3536                  kmcp->kmc_move_later.value.ui64         = 0;
3537 3537                  kmcp->kmc_move_dont_need.value.ui64     = 0;
3538 3538                  kmcp->kmc_move_dont_know.value.ui64     = 0;
3539 3539                  kmcp->kmc_move_hunt_found.value.ui64    = 0;
3540 3540                  kmcp->kmc_move_slabs_freed.value.ui64   = 0;
3541 3541                  kmcp->kmc_defrag.value.ui64             = 0;
3542 3542                  kmcp->kmc_scan.value.ui64               = 0;
3543 3543                  kmcp->kmc_move_reclaimable.value.ui64   = 0;
3544 3544          } else {
3545 3545                  int64_t reclaimable;
3546 3546  
3547 3547                  kmem_defrag_t *kd = cp->cache_defrag;
3548 3548                  kmcp->kmc_move_callbacks.value.ui64     = kd->kmd_callbacks;
3549 3549                  kmcp->kmc_move_yes.value.ui64           = kd->kmd_yes;
3550 3550                  kmcp->kmc_move_no.value.ui64            = kd->kmd_no;
3551 3551                  kmcp->kmc_move_later.value.ui64         = kd->kmd_later;
3552 3552                  kmcp->kmc_move_dont_need.value.ui64     = kd->kmd_dont_need;
3553 3553                  kmcp->kmc_move_dont_know.value.ui64     = kd->kmd_dont_know;
3554 3554                  kmcp->kmc_move_hunt_found.value.ui64    = 0;
3555 3555                  kmcp->kmc_move_slabs_freed.value.ui64   = kd->kmd_slabs_freed;
3556 3556                  kmcp->kmc_defrag.value.ui64             = kd->kmd_defrags;
3557 3557                  kmcp->kmc_scan.value.ui64               = kd->kmd_scans;
3558 3558  
3559 3559                  reclaimable = cp->cache_bufslab - (cp->cache_maxchunks - 1);
3560 3560                  reclaimable = MAX(reclaimable, 0);
3561 3561                  reclaimable += ((uint64_t)reap * cp->cache_magtype->mt_magsize);
3562 3562                  kmcp->kmc_move_reclaimable.value.ui64   = reclaimable;
3563 3563          }
3564 3564  
3565 3565          mutex_exit(&cp->cache_lock);
3566 3566          return (0);
3567 3567  }
3568 3568  
3569 3569  /*
3570 3570   * Return a named statistic about a particular cache.
3571 3571   * This shouldn't be called very often, so it's currently designed for
3572 3572   * simplicity (leverages existing kstat support) rather than efficiency.
3573 3573   */
3574 3574  uint64_t
3575 3575  kmem_cache_stat(kmem_cache_t *cp, char *name)
3576 3576  {
3577 3577          int i;
3578 3578          kstat_t *ksp = cp->cache_kstat;
3579 3579          kstat_named_t *knp = (kstat_named_t *)&kmem_cache_kstat;
3580 3580          uint64_t value = 0;
3581 3581  
3582 3582          if (ksp != NULL) {
3583 3583                  mutex_enter(&kmem_cache_kstat_lock);
3584 3584                  (void) kmem_cache_kstat_update(ksp, KSTAT_READ);
3585 3585                  for (i = 0; i < ksp->ks_ndata; i++) {
3586 3586                          if (strcmp(knp[i].name, name) == 0) {
3587 3587                                  value = knp[i].value.ui64;
3588 3588                                  break;
3589 3589                          }
3590 3590                  }
3591 3591                  mutex_exit(&kmem_cache_kstat_lock);
3592 3592          }
3593 3593          return (value);
3594 3594  }
3595 3595  
3596 3596  /*
3597 3597   * Return an estimate of currently available kernel heap memory.
3598 3598   * On 32-bit systems, physical memory may exceed virtual memory,
3599 3599   * we just truncate the result at 1GB.
3600 3600   */
3601 3601  size_t
3602 3602  kmem_avail(void)
3603 3603  {
3604 3604          spgcnt_t rmem = availrmem - tune.t_minarmem;
3605 3605          spgcnt_t fmem = freemem - minfree;
3606 3606  
3607 3607          return ((size_t)ptob(MIN(MAX(MIN(rmem, fmem), 0),
3608 3608              1 << (30 - PAGESHIFT))));
3609 3609  }
3610 3610  
3611 3611  /*
3612 3612   * Return the maximum amount of memory that is (in theory) allocatable
3613 3613   * from the heap. This may be used as an estimate only since there
3614 3614   * is no guarentee this space will still be available when an allocation
3615 3615   * request is made, nor that the space may be allocated in one big request
3616 3616   * due to kernel heap fragmentation.
3617 3617   */
3618 3618  size_t
3619 3619  kmem_maxavail(void)
3620 3620  {
3621 3621          spgcnt_t pmem = availrmem - tune.t_minarmem;
3622 3622          spgcnt_t vmem = btop(vmem_size(heap_arena, VMEM_FREE));
3623 3623  
3624 3624          return ((size_t)ptob(MAX(MIN(pmem, vmem), 0)));
3625 3625  }
3626 3626  
3627 3627  /*
3628 3628   * Indicate whether memory-intensive kmem debugging is enabled.
3629 3629   */
3630 3630  int
3631 3631  kmem_debugging(void)
3632 3632  {
3633 3633          return (kmem_flags & (KMF_AUDIT | KMF_REDZONE));
3634 3634  }
3635 3635  
3636 3636  /* binning function, sorts finely at the two extremes */
3637 3637  #define KMEM_PARTIAL_SLAB_WEIGHT(sp, binshift)                          \
3638 3638          ((((sp)->slab_refcnt <= (binshift)) ||                          \
3639 3639              (((sp)->slab_chunks - (sp)->slab_refcnt) <= (binshift)))    \
3640 3640              ? -(sp)->slab_refcnt                                        \
3641 3641              : -((binshift) + ((sp)->slab_refcnt >> (binshift))))
3642 3642  
3643 3643  /*
3644 3644   * Minimizing the number of partial slabs on the freelist minimizes
3645 3645   * fragmentation (the ratio of unused buffers held by the slab layer). There are
3646 3646   * two ways to get a slab off of the freelist: 1) free all the buffers on the
3647 3647   * slab, and 2) allocate all the buffers on the slab. It follows that we want
3648 3648   * the most-used slabs at the front of the list where they have the best chance
3649 3649   * of being completely allocated, and the least-used slabs at a safe distance
3650 3650   * from the front to improve the odds that the few remaining buffers will all be
3651 3651   * freed before another allocation can tie up the slab. For that reason a slab
3652 3652   * with a higher slab_refcnt sorts less than than a slab with a lower
3653 3653   * slab_refcnt.
3654 3654   *
3655 3655   * However, if a slab has at least one buffer that is deemed unfreeable, we
3656 3656   * would rather have that slab at the front of the list regardless of
3657 3657   * slab_refcnt, since even one unfreeable buffer makes the entire slab
3658 3658   * unfreeable. If the client returns KMEM_CBRC_NO in response to a cache_move()
3659 3659   * callback, the slab is marked unfreeable for as long as it remains on the
3660 3660   * freelist.
3661 3661   */
3662 3662  static int
3663 3663  kmem_partial_slab_cmp(const void *p0, const void *p1)
3664 3664  {
3665 3665          const kmem_cache_t *cp;
3666 3666          const kmem_slab_t *s0 = p0;
3667 3667          const kmem_slab_t *s1 = p1;
3668 3668          int w0, w1;
3669 3669          size_t binshift;
3670 3670  
3671 3671          ASSERT(KMEM_SLAB_IS_PARTIAL(s0));
3672 3672          ASSERT(KMEM_SLAB_IS_PARTIAL(s1));
3673 3673          ASSERT(s0->slab_cache == s1->slab_cache);
3674 3674          cp = s1->slab_cache;
3675 3675          ASSERT(MUTEX_HELD(&cp->cache_lock));
3676 3676          binshift = cp->cache_partial_binshift;
3677 3677  
3678 3678          /* weight of first slab */
3679 3679          w0 = KMEM_PARTIAL_SLAB_WEIGHT(s0, binshift);
3680 3680          if (s0->slab_flags & KMEM_SLAB_NOMOVE) {
3681 3681                  w0 -= cp->cache_maxchunks;
3682 3682          }
3683 3683  
3684 3684          /* weight of second slab */
3685 3685          w1 = KMEM_PARTIAL_SLAB_WEIGHT(s1, binshift);
3686 3686          if (s1->slab_flags & KMEM_SLAB_NOMOVE) {
3687 3687                  w1 -= cp->cache_maxchunks;
3688 3688          }
3689 3689  
3690 3690          if (w0 < w1)
3691 3691                  return (-1);
3692 3692          if (w0 > w1)
3693 3693                  return (1);
3694 3694  
3695 3695          /* compare pointer values */
3696 3696          if ((uintptr_t)s0 < (uintptr_t)s1)
3697 3697                  return (-1);
3698 3698          if ((uintptr_t)s0 > (uintptr_t)s1)
3699 3699                  return (1);
3700 3700  
3701 3701          return (0);
3702 3702  }
3703 3703  
3704 3704  /*
3705 3705   * It must be valid to call the destructor (if any) on a newly created object.
3706 3706   * That is, the constructor (if any) must leave the object in a valid state for
3707 3707   * the destructor.
3708 3708   */
3709 3709  kmem_cache_t *
3710 3710  kmem_cache_create(
3711 3711          char *name,             /* descriptive name for this cache */
3712 3712          size_t bufsize,         /* size of the objects it manages */
3713 3713          size_t align,           /* required object alignment */
3714 3714          int (*constructor)(void *, void *, int), /* object constructor */
3715 3715          void (*destructor)(void *, void *),     /* object destructor */
3716 3716          void (*reclaim)(void *), /* memory reclaim callback */
3717 3717          void *private,          /* pass-thru arg for constr/destr/reclaim */
3718 3718          vmem_t *vmp,            /* vmem source for slab allocation */
3719 3719          int cflags)             /* cache creation flags */
3720 3720  {
3721 3721          int cpu_seqid;
3722 3722          size_t chunksize;
3723 3723          kmem_cache_t *cp;
3724 3724          kmem_magtype_t *mtp;
3725 3725          size_t csize = KMEM_CACHE_SIZE(max_ncpus);
3726 3726  
3727 3727  #ifdef  DEBUG
3728 3728          /*
3729 3729           * Cache names should conform to the rules for valid C identifiers
3730 3730           */
3731 3731          if (!strident_valid(name)) {
3732 3732                  cmn_err(CE_CONT,
3733 3733                      "kmem_cache_create: '%s' is an invalid cache name\n"
3734 3734                      "cache names must conform to the rules for "
3735 3735                      "C identifiers\n", name);
3736 3736          }
3737 3737  #endif  /* DEBUG */
3738 3738  
3739 3739          if (vmp == NULL)
3740 3740                  vmp = kmem_default_arena;
3741 3741  
3742 3742          /*
3743 3743           * If this kmem cache has an identifier vmem arena as its source, mark
3744 3744           * it such to allow kmem_reap_idspace().
3745 3745           */
3746 3746          ASSERT(!(cflags & KMC_IDENTIFIER));   /* consumer should not set this */
3747 3747          if (vmp->vm_cflags & VMC_IDENTIFIER)
3748 3748                  cflags |= KMC_IDENTIFIER;
3749 3749  
3750 3750          /*
3751 3751           * Get a kmem_cache structure.  We arrange that cp->cache_cpu[]
3752 3752           * is aligned on a KMEM_CPU_CACHE_SIZE boundary to prevent
3753 3753           * false sharing of per-CPU data.
3754 3754           */
3755 3755          cp = vmem_xalloc(kmem_cache_arena, csize, KMEM_CPU_CACHE_SIZE,
3756 3756              P2NPHASE(csize, KMEM_CPU_CACHE_SIZE), 0, NULL, NULL, VM_SLEEP);
3757 3757          bzero(cp, csize);
3758 3758          list_link_init(&cp->cache_link);
3759 3759  
3760 3760          if (align == 0)
3761 3761                  align = KMEM_ALIGN;
3762 3762  
3763 3763          /*
3764 3764           * If we're not at least KMEM_ALIGN aligned, we can't use free
3765 3765           * memory to hold bufctl information (because we can't safely
3766 3766           * perform word loads and stores on it).
3767 3767           */
3768 3768          if (align < KMEM_ALIGN)
3769 3769                  cflags |= KMC_NOTOUCH;
3770 3770  
3771 3771          if (!ISP2(align) || align > vmp->vm_quantum)
3772 3772                  panic("kmem_cache_create: bad alignment %lu", align);
3773 3773  
3774 3774          mutex_enter(&kmem_flags_lock);
3775 3775          if (kmem_flags & KMF_RANDOMIZE)
3776 3776                  kmem_flags = (((kmem_flags | ~KMF_RANDOM) + 1) & KMF_RANDOM) |
3777 3777                      KMF_RANDOMIZE;
3778 3778          cp->cache_flags = (kmem_flags | cflags) & KMF_DEBUG;
3779 3779          mutex_exit(&kmem_flags_lock);
3780 3780  
3781 3781          /*
3782 3782           * Make sure all the various flags are reasonable.
3783 3783           */
3784 3784          ASSERT(!(cflags & KMC_NOHASH) || !(cflags & KMC_NOTOUCH));
3785 3785  
3786 3786          if (cp->cache_flags & KMF_LITE) {
3787 3787                  if (bufsize >= kmem_lite_minsize &&
3788 3788                      align <= kmem_lite_maxalign &&
3789 3789                      P2PHASE(bufsize, kmem_lite_maxalign) != 0) {
3790 3790                          cp->cache_flags |= KMF_BUFTAG;
3791 3791                          cp->cache_flags &= ~(KMF_AUDIT | KMF_FIREWALL);
3792 3792                  } else {
3793 3793                          cp->cache_flags &= ~KMF_DEBUG;
3794 3794                  }
3795 3795          }
3796 3796  
3797 3797          if (cp->cache_flags & KMF_DEADBEEF)
3798 3798                  cp->cache_flags |= KMF_REDZONE;
3799 3799  
3800 3800          if ((cflags & KMC_QCACHE) && (cp->cache_flags & KMF_AUDIT))
3801 3801                  cp->cache_flags |= KMF_NOMAGAZINE;
3802 3802  
3803 3803          if (cflags & KMC_NODEBUG)
3804 3804                  cp->cache_flags &= ~KMF_DEBUG;
3805 3805  
3806 3806          if (cflags & KMC_NOTOUCH)
3807 3807                  cp->cache_flags &= ~KMF_TOUCH;
3808 3808  
3809 3809          if (cflags & KMC_PREFILL)
3810 3810                  cp->cache_flags |= KMF_PREFILL;
3811 3811  
3812 3812          if (cflags & KMC_NOHASH)
3813 3813                  cp->cache_flags &= ~(KMF_AUDIT | KMF_FIREWALL);
3814 3814  
3815 3815          if (cflags & KMC_NOMAGAZINE)
3816 3816                  cp->cache_flags |= KMF_NOMAGAZINE;
3817 3817  
3818 3818          if ((cp->cache_flags & KMF_AUDIT) && !(cflags & KMC_NOTOUCH))
3819 3819                  cp->cache_flags |= KMF_REDZONE;
3820 3820  
3821 3821          if (!(cp->cache_flags & KMF_AUDIT))
3822 3822                  cp->cache_flags &= ~KMF_CONTENTS;
3823 3823  
3824 3824          if ((cp->cache_flags & KMF_BUFTAG) && bufsize >= kmem_minfirewall &&
3825 3825              !(cp->cache_flags & KMF_LITE) && !(cflags & KMC_NOHASH))
3826 3826                  cp->cache_flags |= KMF_FIREWALL;
3827 3827  
3828 3828          if (vmp != kmem_default_arena || kmem_firewall_arena == NULL)
3829 3829                  cp->cache_flags &= ~KMF_FIREWALL;
3830 3830  
3831 3831          if (cp->cache_flags & KMF_FIREWALL) {
3832 3832                  cp->cache_flags &= ~KMF_BUFTAG;
3833 3833                  cp->cache_flags |= KMF_NOMAGAZINE;
3834 3834                  ASSERT(vmp == kmem_default_arena);
3835 3835                  vmp = kmem_firewall_arena;
3836 3836          }
3837 3837  
3838 3838          /*
3839 3839           * Set cache properties.
3840 3840           */
3841 3841          (void) strncpy(cp->cache_name, name, KMEM_CACHE_NAMELEN);
3842 3842          strident_canon(cp->cache_name, KMEM_CACHE_NAMELEN + 1);
3843 3843          cp->cache_bufsize = bufsize;
3844 3844          cp->cache_align = align;
3845 3845          cp->cache_constructor = constructor;
3846 3846          cp->cache_destructor = destructor;
3847 3847          cp->cache_reclaim = reclaim;
3848 3848          cp->cache_private = private;
3849 3849          cp->cache_arena = vmp;
3850 3850          cp->cache_cflags = cflags;
3851 3851  
3852 3852          /*
3853 3853           * Determine the chunk size.
3854 3854           */
3855 3855          chunksize = bufsize;
3856 3856  
3857 3857          if (align >= KMEM_ALIGN) {
3858 3858                  chunksize = P2ROUNDUP(chunksize, KMEM_ALIGN);
3859 3859                  cp->cache_bufctl = chunksize - KMEM_ALIGN;
3860 3860          }
3861 3861  
3862 3862          if (cp->cache_flags & KMF_BUFTAG) {
3863 3863                  cp->cache_bufctl = chunksize;
3864 3864                  cp->cache_buftag = chunksize;
3865 3865                  if (cp->cache_flags & KMF_LITE)
3866 3866                          chunksize += KMEM_BUFTAG_LITE_SIZE(kmem_lite_count);
3867 3867                  else
3868 3868                          chunksize += sizeof (kmem_buftag_t);
3869 3869          }
3870 3870  
3871 3871          if (cp->cache_flags & KMF_DEADBEEF) {
3872 3872                  cp->cache_verify = MIN(cp->cache_buftag, kmem_maxverify);
3873 3873                  if (cp->cache_flags & KMF_LITE)
3874 3874                          cp->cache_verify = sizeof (uint64_t);
3875 3875          }
3876 3876  
3877 3877          cp->cache_contents = MIN(cp->cache_bufctl, kmem_content_maxsave);
3878 3878  
3879 3879          cp->cache_chunksize = chunksize = P2ROUNDUP(chunksize, align);
3880 3880  
3881 3881          /*
3882 3882           * Now that we know the chunk size, determine the optimal slab size.
3883 3883           */
3884 3884          if (vmp == kmem_firewall_arena) {
3885 3885                  cp->cache_slabsize = P2ROUNDUP(chunksize, vmp->vm_quantum);
3886 3886                  cp->cache_mincolor = cp->cache_slabsize - chunksize;
3887 3887                  cp->cache_maxcolor = cp->cache_mincolor;
3888 3888                  cp->cache_flags |= KMF_HASH;
3889 3889                  ASSERT(!(cp->cache_flags & KMF_BUFTAG));
3890 3890          } else if ((cflags & KMC_NOHASH) || (!(cflags & KMC_NOTOUCH) &&
3891 3891              !(cp->cache_flags & KMF_AUDIT) &&
3892 3892              chunksize < vmp->vm_quantum / KMEM_VOID_FRACTION)) {
3893 3893                  cp->cache_slabsize = vmp->vm_quantum;
3894 3894                  cp->cache_mincolor = 0;
3895 3895                  cp->cache_maxcolor =
3896 3896                      (cp->cache_slabsize - sizeof (kmem_slab_t)) % chunksize;
3897 3897                  ASSERT(chunksize + sizeof (kmem_slab_t) <= cp->cache_slabsize);
3898 3898                  ASSERT(!(cp->cache_flags & KMF_AUDIT));
3899 3899          } else {
3900 3900                  size_t chunks, bestfit, waste, slabsize;
3901 3901                  size_t minwaste = LONG_MAX;
3902 3902  
3903 3903                  bestfit = 0;
3904 3904                  for (chunks = 1; chunks <= KMEM_VOID_FRACTION; chunks++) {
3905 3905                          slabsize = P2ROUNDUP(chunksize * chunks,
3906 3906                              vmp->vm_quantum);
3907 3907                          chunks = slabsize / chunksize;
3908 3908                          waste = (slabsize % chunksize) / chunks;
3909 3909                          if (waste < minwaste) {
3910 3910                                  minwaste = waste;
3911 3911                                  bestfit = slabsize;
3912 3912                          }
3913 3913                  }
3914 3914                  if (cflags & KMC_QCACHE)
3915 3915                          bestfit = VMEM_QCACHE_SLABSIZE(vmp->vm_qcache_max);
3916 3916                  cp->cache_slabsize = bestfit;
3917 3917                  cp->cache_mincolor = 0;
3918 3918                  cp->cache_maxcolor = bestfit % chunksize;
3919 3919                  cp->cache_flags |= KMF_HASH;
3920 3920          }
3921 3921  
3922 3922          cp->cache_maxchunks = (cp->cache_slabsize / cp->cache_chunksize);
3923 3923          cp->cache_partial_binshift = highbit(cp->cache_maxchunks / 16) + 1;
3924 3924  
3925 3925          /*
3926 3926           * Disallowing prefill when either the DEBUG or HASH flag is set or when
3927 3927           * there is a constructor avoids some tricky issues with debug setup
3928 3928           * that may be revisited later. We cannot allow prefill in a
3929 3929           * metadata cache because of potential recursion.
3930 3930           */
3931 3931          if (vmp == kmem_msb_arena ||
3932 3932              cp->cache_flags & (KMF_HASH | KMF_BUFTAG) ||
3933 3933              cp->cache_constructor != NULL)
3934 3934                  cp->cache_flags &= ~KMF_PREFILL;
3935 3935  
3936 3936          if (cp->cache_flags & KMF_HASH) {
3937 3937                  ASSERT(!(cflags & KMC_NOHASH));
3938 3938                  cp->cache_bufctl_cache = (cp->cache_flags & KMF_AUDIT) ?
3939 3939                      kmem_bufctl_audit_cache : kmem_bufctl_cache;
3940 3940          }
3941 3941  
3942 3942          if (cp->cache_maxcolor >= vmp->vm_quantum)
3943 3943                  cp->cache_maxcolor = vmp->vm_quantum - 1;
3944 3944  
3945 3945          cp->cache_color = cp->cache_mincolor;
3946 3946  
3947 3947          /*
3948 3948           * Initialize the rest of the slab layer.
3949 3949           */
3950 3950          mutex_init(&cp->cache_lock, NULL, MUTEX_DEFAULT, NULL);
3951 3951  
3952 3952          avl_create(&cp->cache_partial_slabs, kmem_partial_slab_cmp,
3953 3953              sizeof (kmem_slab_t), offsetof(kmem_slab_t, slab_link));
3954 3954          /* LINTED: E_TRUE_LOGICAL_EXPR */
3955 3955          ASSERT(sizeof (list_node_t) <= sizeof (avl_node_t));
3956 3956          /* reuse partial slab AVL linkage for complete slab list linkage */
3957 3957          list_create(&cp->cache_complete_slabs,
3958 3958              sizeof (kmem_slab_t), offsetof(kmem_slab_t, slab_link));
3959 3959  
3960 3960          if (cp->cache_flags & KMF_HASH) {
3961 3961                  cp->cache_hash_table = vmem_alloc(kmem_hash_arena,
3962 3962                      KMEM_HASH_INITIAL * sizeof (void *), VM_SLEEP);
3963 3963                  bzero(cp->cache_hash_table,
3964 3964                      KMEM_HASH_INITIAL * sizeof (void *));
3965 3965                  cp->cache_hash_mask = KMEM_HASH_INITIAL - 1;
3966 3966                  cp->cache_hash_shift = highbit((ulong_t)chunksize) - 1;
3967 3967          }
3968 3968  
3969 3969          /*
3970 3970           * Initialize the depot.
3971 3971           */
3972 3972          mutex_init(&cp->cache_depot_lock, NULL, MUTEX_DEFAULT, NULL);
3973 3973  
3974 3974          for (mtp = kmem_magtype; chunksize <= mtp->mt_minbuf; mtp++)
3975 3975                  continue;
3976 3976  
3977 3977          cp->cache_magtype = mtp;
3978 3978  
3979 3979          /*
3980 3980           * Initialize the CPU layer.
3981 3981           */
3982 3982          for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) {
3983 3983                  kmem_cpu_cache_t *ccp = &cp->cache_cpu[cpu_seqid];
3984 3984                  mutex_init(&ccp->cc_lock, NULL, MUTEX_DEFAULT, NULL);
3985 3985                  ccp->cc_flags = cp->cache_flags;
3986 3986                  ccp->cc_rounds = -1;
3987 3987                  ccp->cc_prounds = -1;
3988 3988          }
3989 3989  
3990 3990          /*
3991 3991           * Create the cache's kstats.
3992 3992           */
3993 3993          if ((cp->cache_kstat = kstat_create("unix", 0, cp->cache_name,
3994 3994              "kmem_cache", KSTAT_TYPE_NAMED,
3995 3995              sizeof (kmem_cache_kstat) / sizeof (kstat_named_t),
3996 3996              KSTAT_FLAG_VIRTUAL)) != NULL) {
3997 3997                  cp->cache_kstat->ks_data = &kmem_cache_kstat;
3998 3998                  cp->cache_kstat->ks_update = kmem_cache_kstat_update;
3999 3999                  cp->cache_kstat->ks_private = cp;
4000 4000                  cp->cache_kstat->ks_lock = &kmem_cache_kstat_lock;
4001 4001                  kstat_install(cp->cache_kstat);
4002 4002          }
4003 4003  
4004 4004          /*
4005 4005           * Add the cache to the global list.  This makes it visible
4006 4006           * to kmem_update(), so the cache must be ready for business.
4007 4007           */
4008 4008          mutex_enter(&kmem_cache_lock);
4009 4009          list_insert_tail(&kmem_caches, cp);
4010 4010          mutex_exit(&kmem_cache_lock);
4011 4011  
4012 4012          if (kmem_ready)
4013 4013                  kmem_cache_magazine_enable(cp);
4014 4014  
4015 4015          return (cp);
4016 4016  }
4017 4017  
4018 4018  static int
4019 4019  kmem_move_cmp(const void *buf, const void *p)
4020 4020  {
4021 4021          const kmem_move_t *kmm = p;
4022 4022          uintptr_t v1 = (uintptr_t)buf;
4023 4023          uintptr_t v2 = (uintptr_t)kmm->kmm_from_buf;
4024 4024          return (v1 < v2 ? -1 : (v1 > v2 ? 1 : 0));
4025 4025  }
4026 4026  
4027 4027  static void
4028 4028  kmem_reset_reclaim_threshold(kmem_defrag_t *kmd)
4029 4029  {
4030 4030          kmd->kmd_reclaim_numer = 1;
4031 4031  }
4032 4032  
4033 4033  /*
4034 4034   * Initially, when choosing candidate slabs for buffers to move, we want to be
4035 4035   * very selective and take only slabs that are less than
4036 4036   * (1 / KMEM_VOID_FRACTION) allocated. If we have difficulty finding candidate
4037 4037   * slabs, then we raise the allocation ceiling incrementally. The reclaim
4038 4038   * threshold is reset to (1 / KMEM_VOID_FRACTION) as soon as the cache is no
4039 4039   * longer fragmented.
4040 4040   */
4041 4041  static void
4042 4042  kmem_adjust_reclaim_threshold(kmem_defrag_t *kmd, int direction)
4043 4043  {
4044 4044          if (direction > 0) {
4045 4045                  /* make it easier to find a candidate slab */
4046 4046                  if (kmd->kmd_reclaim_numer < (KMEM_VOID_FRACTION - 1)) {
4047 4047                          kmd->kmd_reclaim_numer++;
4048 4048                  }
4049 4049          } else {
4050 4050                  /* be more selective */
4051 4051                  if (kmd->kmd_reclaim_numer > 1) {
4052 4052                          kmd->kmd_reclaim_numer--;
4053 4053                  }
4054 4054          }
4055 4055  }
4056 4056  
4057 4057  void
4058 4058  kmem_cache_set_move(kmem_cache_t *cp,
4059 4059      kmem_cbrc_t (*move)(void *, void *, size_t, void *))
4060 4060  {
4061 4061          kmem_defrag_t *defrag;
4062 4062  
4063 4063          ASSERT(move != NULL);
4064 4064          /*
4065 4065           * The consolidator does not support NOTOUCH caches because kmem cannot
4066 4066           * initialize their slabs with the 0xbaddcafe memory pattern, which sets
4067 4067           * a low order bit usable by clients to distinguish uninitialized memory
4068 4068           * from known objects (see kmem_slab_create).
4069 4069           */
4070 4070          ASSERT(!(cp->cache_cflags & KMC_NOTOUCH));
4071 4071          ASSERT(!(cp->cache_cflags & KMC_IDENTIFIER));
4072 4072  
4073 4073          /*
4074 4074           * We should not be holding anyone's cache lock when calling
4075 4075           * kmem_cache_alloc(), so allocate in all cases before acquiring the
4076 4076           * lock.
4077 4077           */
4078 4078          defrag = kmem_cache_alloc(kmem_defrag_cache, KM_SLEEP);
4079 4079  
4080 4080          mutex_enter(&cp->cache_lock);
4081 4081  
4082 4082          if (KMEM_IS_MOVABLE(cp)) {
4083 4083                  if (cp->cache_move == NULL) {
4084 4084                          ASSERT(cp->cache_slab_alloc == 0);
4085 4085  
4086 4086                          cp->cache_defrag = defrag;
4087 4087                          defrag = NULL; /* nothing to free */
4088 4088                          bzero(cp->cache_defrag, sizeof (kmem_defrag_t));
4089 4089                          avl_create(&cp->cache_defrag->kmd_moves_pending,
4090 4090                              kmem_move_cmp, sizeof (kmem_move_t),
4091 4091                              offsetof(kmem_move_t, kmm_entry));
4092 4092                          /* LINTED: E_TRUE_LOGICAL_EXPR */
4093 4093                          ASSERT(sizeof (list_node_t) <= sizeof (avl_node_t));
4094 4094                          /* reuse the slab's AVL linkage for deadlist linkage */
4095 4095                          list_create(&cp->cache_defrag->kmd_deadlist,
4096 4096                              sizeof (kmem_slab_t),
4097 4097                              offsetof(kmem_slab_t, slab_link));
4098 4098                          kmem_reset_reclaim_threshold(cp->cache_defrag);
4099 4099                  }
4100 4100                  cp->cache_move = move;
4101 4101          }
4102 4102  
4103 4103          mutex_exit(&cp->cache_lock);
4104 4104  
4105 4105          if (defrag != NULL) {
4106 4106                  kmem_cache_free(kmem_defrag_cache, defrag); /* unused */
4107 4107          }
4108 4108  }
4109 4109  
4110 4110  void
4111 4111  kmem_cache_destroy(kmem_cache_t *cp)
4112 4112  {
4113 4113          int cpu_seqid;
4114 4114  
4115 4115          /*
4116 4116           * Remove the cache from the global cache list so that no one else
4117 4117           * can schedule tasks on its behalf, wait for any pending tasks to
4118 4118           * complete, purge the cache, and then destroy it.
4119 4119           */
4120 4120          mutex_enter(&kmem_cache_lock);
4121 4121          list_remove(&kmem_caches, cp);
4122 4122          mutex_exit(&kmem_cache_lock);
4123 4123  
4124 4124          if (kmem_taskq != NULL)
4125 4125                  taskq_wait(kmem_taskq);
4126 4126  
4127 4127          if (kmem_move_taskq != NULL && cp->cache_defrag != NULL)
4128 4128                  taskq_wait(kmem_move_taskq);
4129 4129  
4130 4130          kmem_cache_magazine_purge(cp);
4131 4131  
4132 4132          mutex_enter(&cp->cache_lock);
4133 4133          if (cp->cache_buftotal != 0)
4134 4134                  cmn_err(CE_WARN, "kmem_cache_destroy: '%s' (%p) not empty",
4135 4135                      cp->cache_name, (void *)cp);
4136 4136          if (cp->cache_defrag != NULL) {
4137 4137                  avl_destroy(&cp->cache_defrag->kmd_moves_pending);
4138 4138                  list_destroy(&cp->cache_defrag->kmd_deadlist);
4139 4139                  kmem_cache_free(kmem_defrag_cache, cp->cache_defrag);
4140 4140                  cp->cache_defrag = NULL;
4141 4141          }
4142 4142          /*
4143 4143           * The cache is now dead.  There should be no further activity.  We
4144 4144           * enforce this by setting land mines in the constructor, destructor,
4145 4145           * reclaim, and move routines that induce a kernel text fault if
4146 4146           * invoked.
4147 4147           */
4148 4148          cp->cache_constructor = (int (*)(void *, void *, int))1;
4149 4149          cp->cache_destructor = (void (*)(void *, void *))2;
4150 4150          cp->cache_reclaim = (void (*)(void *))3;
4151 4151          cp->cache_move = (kmem_cbrc_t (*)(void *, void *, size_t, void *))4;
4152 4152          mutex_exit(&cp->cache_lock);
4153 4153  
4154 4154          kstat_delete(cp->cache_kstat);
4155 4155  
4156 4156          if (cp->cache_hash_table != NULL)
4157 4157                  vmem_free(kmem_hash_arena, cp->cache_hash_table,
4158 4158                      (cp->cache_hash_mask + 1) * sizeof (void *));
4159 4159  
4160 4160          for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++)
4161 4161                  mutex_destroy(&cp->cache_cpu[cpu_seqid].cc_lock);
4162 4162  
4163 4163          mutex_destroy(&cp->cache_depot_lock);
4164 4164          mutex_destroy(&cp->cache_lock);
4165 4165  
4166 4166          vmem_free(kmem_cache_arena, cp, KMEM_CACHE_SIZE(max_ncpus));
4167 4167  }
4168 4168  
4169 4169  /*ARGSUSED*/
4170 4170  static int
4171 4171  kmem_cpu_setup(cpu_setup_t what, int id, void *arg)
4172 4172  {
4173 4173          ASSERT(MUTEX_HELD(&cpu_lock));
4174 4174          if (what == CPU_UNCONFIG) {
4175 4175                  kmem_cache_applyall(kmem_cache_magazine_purge,
4176 4176                      kmem_taskq, TQ_SLEEP);
4177 4177                  kmem_cache_applyall(kmem_cache_magazine_enable,
4178 4178                      kmem_taskq, TQ_SLEEP);
4179 4179          }
4180 4180          return (0);
4181 4181  }
4182 4182  
4183 4183  static void
4184 4184  kmem_alloc_caches_create(const int *array, size_t count,
4185 4185      kmem_cache_t **alloc_table, size_t maxbuf, uint_t shift)
4186 4186  {
4187 4187          char name[KMEM_CACHE_NAMELEN + 1];
4188 4188          size_t table_unit = (1 << shift); /* range of one alloc_table entry */
4189 4189          size_t size = table_unit;
4190 4190          int i;
4191 4191  
4192 4192          for (i = 0; i < count; i++) {
4193 4193                  size_t cache_size = array[i];
4194 4194                  size_t align = KMEM_ALIGN;
4195 4195                  kmem_cache_t *cp;
4196 4196  
4197 4197                  /* if the table has an entry for maxbuf, we're done */
4198 4198                  if (size > maxbuf)
4199 4199                          break;
4200 4200  
4201 4201                  /* cache size must be a multiple of the table unit */
4202 4202                  ASSERT(P2PHASE(cache_size, table_unit) == 0);
4203 4203  
4204 4204                  /*
4205 4205                   * If they allocate a multiple of the coherency granularity,
4206 4206                   * they get a coherency-granularity-aligned address.
4207 4207                   */
4208 4208                  if (IS_P2ALIGNED(cache_size, 64))
4209 4209                          align = 64;
4210 4210                  if (IS_P2ALIGNED(cache_size, PAGESIZE))
4211 4211                          align = PAGESIZE;
4212 4212                  (void) snprintf(name, sizeof (name),
4213 4213                      "kmem_alloc_%lu", cache_size);
4214 4214                  cp = kmem_cache_create(name, cache_size, align,
4215 4215                      NULL, NULL, NULL, NULL, NULL, KMC_KMEM_ALLOC);
4216 4216  
4217 4217                  while (size <= cache_size) {
4218 4218                          alloc_table[(size - 1) >> shift] = cp;
4219 4219                          size += table_unit;
4220 4220                  }
4221 4221          }
4222 4222  
4223 4223          ASSERT(size > maxbuf);          /* i.e. maxbuf <= max(cache_size) */
4224 4224  }
4225 4225  
4226 4226  static void
4227 4227  kmem_cache_init(int pass, int use_large_pages)
4228 4228  {
4229 4229          int i;
4230 4230          size_t maxbuf;
4231 4231          kmem_magtype_t *mtp;
4232 4232  
4233 4233          for (i = 0; i < sizeof (kmem_magtype) / sizeof (*mtp); i++) {
4234 4234                  char name[KMEM_CACHE_NAMELEN + 1];
4235 4235  
4236 4236                  mtp = &kmem_magtype[i];
4237 4237                  (void) sprintf(name, "kmem_magazine_%d", mtp->mt_magsize);
4238 4238                  mtp->mt_cache = kmem_cache_create(name,
4239 4239                      (mtp->mt_magsize + 1) * sizeof (void *),
4240 4240                      mtp->mt_align, NULL, NULL, NULL, NULL,
4241 4241                      kmem_msb_arena, KMC_NOHASH);
4242 4242          }
4243 4243  
4244 4244          kmem_slab_cache = kmem_cache_create("kmem_slab_cache",
4245 4245              sizeof (kmem_slab_t), 0, NULL, NULL, NULL, NULL,
4246 4246              kmem_msb_arena, KMC_NOHASH);
4247 4247  
4248 4248          kmem_bufctl_cache = kmem_cache_create("kmem_bufctl_cache",
4249 4249              sizeof (kmem_bufctl_t), 0, NULL, NULL, NULL, NULL,
4250 4250              kmem_msb_arena, KMC_NOHASH);
4251 4251  
4252 4252          kmem_bufctl_audit_cache = kmem_cache_create("kmem_bufctl_audit_cache",
4253 4253              sizeof (kmem_bufctl_audit_t), 0, NULL, NULL, NULL, NULL,
4254 4254              kmem_msb_arena, KMC_NOHASH);
4255 4255  
4256 4256          if (pass == 2) {
4257 4257                  kmem_va_arena = vmem_create("kmem_va",
4258 4258                      NULL, 0, PAGESIZE,
4259 4259                      vmem_alloc, vmem_free, heap_arena,
4260 4260                      8 * PAGESIZE, VM_SLEEP);
4261 4261  
4262 4262                  if (use_large_pages) {
4263 4263                          kmem_default_arena = vmem_xcreate("kmem_default",
4264 4264                              NULL, 0, PAGESIZE,
4265 4265                              segkmem_alloc_lp, segkmem_free_lp, kmem_va_arena,
4266 4266                              0, VMC_DUMPSAFE | VM_SLEEP);
4267 4267                  } else {
4268 4268                          kmem_default_arena = vmem_create("kmem_default",
4269 4269                              NULL, 0, PAGESIZE,
4270 4270                              segkmem_alloc, segkmem_free, kmem_va_arena,
4271 4271                              0, VMC_DUMPSAFE | VM_SLEEP);
4272 4272                  }
4273 4273  
4274 4274                  /* Figure out what our maximum cache size is */
4275 4275                  maxbuf = kmem_max_cached;
4276 4276                  if (maxbuf <= KMEM_MAXBUF) {
4277 4277                          maxbuf = 0;
4278 4278                          kmem_max_cached = KMEM_MAXBUF;
4279 4279                  } else {
4280 4280                          size_t size = 0;
4281 4281                          size_t max =
4282 4282                              sizeof (kmem_big_alloc_sizes) / sizeof (int);
4283 4283                          /*
4284 4284                           * Round maxbuf up to an existing cache size.  If maxbuf
4285 4285                           * is larger than the largest cache, we truncate it to
4286 4286                           * the largest cache's size.
4287 4287                           */
4288 4288                          for (i = 0; i < max; i++) {
4289 4289                                  size = kmem_big_alloc_sizes[i];
4290 4290                                  if (maxbuf <= size)
4291 4291                                          break;
4292 4292                          }
4293 4293                          kmem_max_cached = maxbuf = size;
4294 4294                  }
4295 4295  
4296 4296                  /*
4297 4297                   * The big alloc table may not be completely overwritten, so
4298 4298                   * we clear out any stale cache pointers from the first pass.
4299 4299                   */
4300 4300                  bzero(kmem_big_alloc_table, sizeof (kmem_big_alloc_table));
4301 4301          } else {
4302 4302                  /*
4303 4303                   * During the first pass, the kmem_alloc_* caches
4304 4304                   * are treated as metadata.
4305 4305                   */
4306 4306                  kmem_default_arena = kmem_msb_arena;
4307 4307                  maxbuf = KMEM_BIG_MAXBUF_32BIT;
4308 4308          }
4309 4309  
4310 4310          /*
4311 4311           * Set up the default caches to back kmem_alloc()
4312 4312           */
4313 4313          kmem_alloc_caches_create(
4314 4314              kmem_alloc_sizes, sizeof (kmem_alloc_sizes) / sizeof (int),
4315 4315              kmem_alloc_table, KMEM_MAXBUF, KMEM_ALIGN_SHIFT);
4316 4316  
4317 4317          kmem_alloc_caches_create(
4318 4318              kmem_big_alloc_sizes, sizeof (kmem_big_alloc_sizes) / sizeof (int),
4319 4319              kmem_big_alloc_table, maxbuf, KMEM_BIG_SHIFT);
4320 4320  
4321 4321          kmem_big_alloc_table_max = maxbuf >> KMEM_BIG_SHIFT;
4322 4322  }
4323 4323  
4324 4324  void
4325 4325  kmem_init(void)
4326 4326  {
4327 4327          kmem_cache_t *cp;
4328 4328          int old_kmem_flags = kmem_flags;
4329 4329          int use_large_pages = 0;
4330 4330          size_t maxverify, minfirewall;
4331 4331  
4332 4332          kstat_init();
4333 4333  
4334 4334          /*
4335 4335           * Don't do firewalled allocations if the heap is less than 1TB
4336 4336           * (i.e. on a 32-bit kernel)
4337 4337           * The resulting VM_NEXTFIT allocations would create too much
4338 4338           * fragmentation in a small heap.
4339 4339           */
4340 4340  #if defined(_LP64)
4341 4341          maxverify = minfirewall = PAGESIZE / 2;
4342 4342  #else
4343 4343          maxverify = minfirewall = ULONG_MAX;
4344 4344  #endif
4345 4345  
4346 4346          /* LINTED */
4347 4347          ASSERT(sizeof (kmem_cpu_cache_t) == KMEM_CPU_CACHE_SIZE);
4348 4348  
4349 4349          list_create(&kmem_caches, sizeof (kmem_cache_t),
4350 4350              offsetof(kmem_cache_t, cache_link));
4351 4351  
4352 4352          kmem_metadata_arena = vmem_create("kmem_metadata", NULL, 0, PAGESIZE,
4353 4353              vmem_alloc, vmem_free, heap_arena, 8 * PAGESIZE,
4354 4354              VM_SLEEP | VMC_NO_QCACHE);
4355 4355  
4356 4356          kmem_msb_arena = vmem_create("kmem_msb", NULL, 0,
4357 4357              PAGESIZE, segkmem_alloc, segkmem_free, kmem_metadata_arena, 0,
4358 4358              VMC_DUMPSAFE | VM_SLEEP);
4359 4359  
4360 4360          kmem_cache_arena = vmem_create("kmem_cache", NULL, 0, KMEM_ALIGN,
4361 4361              segkmem_alloc, segkmem_free, kmem_metadata_arena, 0, VM_SLEEP);
4362 4362  
4363 4363          kmem_hash_arena = vmem_create("kmem_hash", NULL, 0, KMEM_ALIGN,
4364 4364              segkmem_alloc, segkmem_free, kmem_metadata_arena, 0, VM_SLEEP);
4365 4365  
4366 4366          kmem_log_arena = vmem_create("kmem_log", NULL, 0, KMEM_ALIGN,
4367 4367              segkmem_alloc, segkmem_free, heap_arena, 0, VM_SLEEP);
4368 4368  
4369 4369          kmem_firewall_va_arena = vmem_create("kmem_firewall_va",
4370 4370              NULL, 0, PAGESIZE,
4371 4371              kmem_firewall_va_alloc, kmem_firewall_va_free, heap_arena,
4372 4372              0, VM_SLEEP);
4373 4373  
4374 4374          kmem_firewall_arena = vmem_create("kmem_firewall", NULL, 0, PAGESIZE,
4375 4375              segkmem_alloc, segkmem_free, kmem_firewall_va_arena, 0,
4376 4376              VMC_DUMPSAFE | VM_SLEEP);
4377 4377  
4378 4378          /* temporary oversize arena for mod_read_system_file */
4379 4379          kmem_oversize_arena = vmem_create("kmem_oversize", NULL, 0, PAGESIZE,
4380 4380              segkmem_alloc, segkmem_free, heap_arena, 0, VM_SLEEP);
4381 4381  
4382 4382          kmem_reap_interval = 15 * hz;
4383 4383  
4384 4384          /*
4385 4385           * Read /etc/system.  This is a chicken-and-egg problem because
4386 4386           * kmem_flags may be set in /etc/system, but mod_read_system_file()
4387 4387           * needs to use the allocator.  The simplest solution is to create
4388 4388           * all the standard kmem caches, read /etc/system, destroy all the
4389 4389           * caches we just created, and then create them all again in light
4390 4390           * of the (possibly) new kmem_flags and other kmem tunables.
4391 4391           */
4392 4392          kmem_cache_init(1, 0);
4393 4393  
4394 4394          mod_read_system_file(boothowto & RB_ASKNAME);
4395 4395  
4396 4396          while ((cp = list_tail(&kmem_caches)) != NULL)
4397 4397                  kmem_cache_destroy(cp);
4398 4398  
4399 4399          vmem_destroy(kmem_oversize_arena);
4400 4400  
4401 4401          if (old_kmem_flags & KMF_STICKY)
4402 4402                  kmem_flags = old_kmem_flags;
4403 4403  
4404 4404          if (!(kmem_flags & KMF_AUDIT))
4405 4405                  vmem_seg_size = offsetof(vmem_seg_t, vs_thread);
4406 4406  
4407 4407          if (kmem_maxverify == 0)
4408 4408                  kmem_maxverify = maxverify;
4409 4409  
4410 4410          if (kmem_minfirewall == 0)
4411 4411                  kmem_minfirewall = minfirewall;
4412 4412  
4413 4413          /*
4414 4414           * give segkmem a chance to figure out if we are using large pages
4415 4415           * for the kernel heap
4416 4416           */
4417 4417          use_large_pages = segkmem_lpsetup();
4418 4418  
4419 4419          /*
4420 4420           * To protect against corruption, we keep the actual number of callers
4421 4421           * KMF_LITE records seperate from the tunable.  We arbitrarily clamp
4422 4422           * to 16, since the overhead for small buffers quickly gets out of
4423 4423           * hand.
4424 4424           *
4425 4425           * The real limit would depend on the needs of the largest KMC_NOHASH
4426 4426           * cache.
4427 4427           */
4428 4428          kmem_lite_count = MIN(MAX(0, kmem_lite_pcs), 16);
4429 4429          kmem_lite_pcs = kmem_lite_count;
4430 4430  
4431 4431          /*
4432 4432           * Normally, we firewall oversized allocations when possible, but
4433 4433           * if we are using large pages for kernel memory, and we don't have
4434 4434           * any non-LITE debugging flags set, we want to allocate oversized
4435 4435           * buffers from large pages, and so skip the firewalling.
4436 4436           */
4437 4437          if (use_large_pages &&
4438 4438              ((kmem_flags & KMF_LITE) || !(kmem_flags & KMF_DEBUG))) {
4439 4439                  kmem_oversize_arena = vmem_xcreate("kmem_oversize", NULL, 0,
4440 4440                      PAGESIZE, segkmem_alloc_lp, segkmem_free_lp, heap_arena,
4441 4441                      0, VMC_DUMPSAFE | VM_SLEEP);
4442 4442          } else {
4443 4443                  kmem_oversize_arena = vmem_create("kmem_oversize",
4444 4444                      NULL, 0, PAGESIZE,
4445 4445                      segkmem_alloc, segkmem_free, kmem_minfirewall < ULONG_MAX?
4446 4446                      kmem_firewall_va_arena : heap_arena, 0, VMC_DUMPSAFE |
4447 4447                      VM_SLEEP);
4448 4448          }
4449 4449  
4450 4450          kmem_cache_init(2, use_large_pages);
4451 4451  
4452 4452          if (kmem_flags & (KMF_AUDIT | KMF_RANDOMIZE)) {
4453 4453                  if (kmem_transaction_log_size == 0)
4454 4454                          kmem_transaction_log_size = kmem_maxavail() / 50;
4455 4455                  kmem_transaction_log = kmem_log_init(kmem_transaction_log_size);
4456 4456          }
4457 4457  
4458 4458          if (kmem_flags & (KMF_CONTENTS | KMF_RANDOMIZE)) {
4459 4459                  if (kmem_content_log_size == 0)
4460 4460                          kmem_content_log_size = kmem_maxavail() / 50;
4461 4461                  kmem_content_log = kmem_log_init(kmem_content_log_size);
4462 4462          }
4463 4463  
4464 4464          kmem_failure_log = kmem_log_init(kmem_failure_log_size);
4465 4465          kmem_slab_log = kmem_log_init(kmem_slab_log_size);
4466 4466          kmem_zerosized_log = kmem_log_init(kmem_zerosized_log_size);
4467 4467  
4468 4468          /*
4469 4469           * Initialize STREAMS message caches so allocb() is available.
4470 4470           * This allows us to initialize the logging framework (cmn_err(9F),
4471 4471           * strlog(9F), etc) so we can start recording messages.
4472 4472           */
4473 4473          streams_msg_init();
4474 4474  
4475 4475          /*
4476 4476           * Initialize the ZSD framework in Zones so modules loaded henceforth
4477 4477           * can register their callbacks.
4478 4478           */
4479 4479          zone_zsd_init();
4480 4480  
4481 4481          log_init();
4482 4482          taskq_init();
4483 4483  
4484 4484          /*
4485 4485           * Warn about invalid or dangerous values of kmem_flags.
4486 4486           * Always warn about unsupported values.
4487 4487           */
4488 4488          if (((kmem_flags & ~(KMF_AUDIT | KMF_DEADBEEF | KMF_REDZONE |
4489 4489              KMF_CONTENTS | KMF_LITE)) != 0) ||
4490 4490              ((kmem_flags & KMF_LITE) && kmem_flags != KMF_LITE))
4491 4491                  cmn_err(CE_WARN, "kmem_flags set to unsupported value 0x%x.",
4492 4492                      kmem_flags);
4493 4493  
4494 4494  #ifdef DEBUG
4495 4495          if ((kmem_flags & KMF_DEBUG) == 0)
4496 4496                  cmn_err(CE_NOTE, "kmem debugging disabled.");
4497 4497  #else
4498 4498          /*
4499 4499           * For non-debug kernels, the only "normal" flags are 0, KMF_LITE,
4500 4500           * KMF_REDZONE, and KMF_CONTENTS (the last because it is only enabled
4501 4501           * if KMF_AUDIT is set). We should warn the user about the performance
4502 4502           * penalty of KMF_AUDIT or KMF_DEADBEEF if they are set and KMF_LITE
4503 4503           * isn't set (since that disables AUDIT).
4504 4504           */
4505 4505          if (!(kmem_flags & KMF_LITE) &&
4506 4506              (kmem_flags & (KMF_AUDIT | KMF_DEADBEEF)) != 0)
4507 4507                  cmn_err(CE_WARN, "High-overhead kmem debugging features "
4508 4508                      "enabled (kmem_flags = 0x%x).  Performance degradation "
4509 4509                      "and large memory overhead possible.", kmem_flags);
4510 4510  #endif /* not DEBUG */
4511 4511  
4512 4512          kmem_cache_applyall(kmem_cache_magazine_enable, NULL, TQ_SLEEP);
4513 4513  
4514 4514          kmem_ready = 1;
4515 4515  
4516 4516          /*
4517 4517           * Initialize the platform-specific aligned/DMA memory allocator.
4518 4518           */
4519 4519          ka_init();
4520 4520  
4521 4521          /*
4522 4522           * Initialize 32-bit ID cache.
4523 4523           */
4524 4524          id32_init();
4525 4525  
4526 4526          /*
4527 4527           * Initialize the networking stack so modules loaded can
4528 4528           * register their callbacks.
4529 4529           */
4530 4530          netstack_init();
4531 4531  }
4532 4532  
4533 4533  static void
4534 4534  kmem_move_init(void)
4535 4535  {
4536 4536          kmem_defrag_cache = kmem_cache_create("kmem_defrag_cache",
4537 4537              sizeof (kmem_defrag_t), 0, NULL, NULL, NULL, NULL,
4538 4538              kmem_msb_arena, KMC_NOHASH);
4539 4539          kmem_move_cache = kmem_cache_create("kmem_move_cache",
4540 4540              sizeof (kmem_move_t), 0, NULL, NULL, NULL, NULL,
4541 4541              kmem_msb_arena, KMC_NOHASH);
4542 4542  
4543 4543          /*
4544 4544           * kmem guarantees that move callbacks are sequential and that even
4545 4545           * across multiple caches no two moves ever execute simultaneously.
4546 4546           * Move callbacks are processed on a separate taskq so that client code
4547 4547           * does not interfere with internal maintenance tasks.
4548 4548           */
4549 4549          kmem_move_taskq = taskq_create_instance("kmem_move_taskq", 0, 1,
4550 4550              minclsyspri, 100, INT_MAX, TASKQ_PREPOPULATE);
4551 4551  }
4552 4552  
4553 4553  void
4554 4554  kmem_thread_init(void)
4555 4555  {
4556 4556          kmem_move_init();
4557 4557  
4558 4558          /*
4559 4559           * This taskq is used for various kmem maintenance functions, including
4560 4560           * kmem_reap().   When maintenance is required on every cache,
4561 4561           * kmem_cache_applyall() dispatches one task per cache onto this queue.
4562 4562           *
4563 4563           * In the case of kmem_reap(), the system may be under increasingly
4564 4564           * dire memory pressure and may not be able to allocate a new task
4565 4565           * entry.  The count of entries to prepopulate (below) should cover at
4566 4566           * least as many caches as we generally expect to exist on the system
4567 4567           * so that they may all be scheduled for reaping under those
4568 4568           * conditions.
4569 4569           */
4570 4570          kmem_taskq = taskq_create_instance("kmem_taskq", 0, 1, minclsyspri,
4571 4571              600, INT_MAX, TASKQ_PREPOPULATE);
4572 4572  }
4573 4573  
4574 4574  void
4575 4575  kmem_mp_init(void)
4576 4576  {
4577 4577          mutex_enter(&cpu_lock);
4578 4578          register_cpu_setup_func(kmem_cpu_setup, NULL);
4579 4579          mutex_exit(&cpu_lock);
4580 4580  
4581 4581          kmem_update_timeout(NULL);
4582 4582  
4583 4583          taskq_mp_init();
4584 4584  }
4585 4585  
4586 4586  /*
4587 4587   * Return the slab of the allocated buffer, or NULL if the buffer is not
4588 4588   * allocated. This function may be called with a known slab address to determine
4589 4589   * whether or not the buffer is allocated, or with a NULL slab address to obtain
4590 4590   * an allocated buffer's slab.
4591 4591   */
4592 4592  static kmem_slab_t *
4593 4593  kmem_slab_allocated(kmem_cache_t *cp, kmem_slab_t *sp, void *buf)
4594 4594  {
4595 4595          kmem_bufctl_t *bcp, *bufbcp;
4596 4596  
4597 4597          ASSERT(MUTEX_HELD(&cp->cache_lock));
4598 4598          ASSERT(sp == NULL || KMEM_SLAB_MEMBER(sp, buf));
4599 4599  
4600 4600          if (cp->cache_flags & KMF_HASH) {
4601 4601                  for (bcp = *KMEM_HASH(cp, buf);
4602 4602                      (bcp != NULL) && (bcp->bc_addr != buf);
4603 4603                      bcp = bcp->bc_next) {
4604 4604                          continue;
4605 4605                  }
4606 4606                  ASSERT(sp != NULL && bcp != NULL ? sp == bcp->bc_slab : 1);
4607 4607                  return (bcp == NULL ? NULL : bcp->bc_slab);
4608 4608          }
4609 4609  
4610 4610          if (sp == NULL) {
4611 4611                  sp = KMEM_SLAB(cp, buf);
4612 4612          }
4613 4613          bufbcp = KMEM_BUFCTL(cp, buf);
4614 4614          for (bcp = sp->slab_head;
4615 4615              (bcp != NULL) && (bcp != bufbcp);
4616 4616              bcp = bcp->bc_next) {
4617 4617                  continue;
4618 4618          }
4619 4619          return (bcp == NULL ? sp : NULL);
4620 4620  }
4621 4621  
4622 4622  static boolean_t
4623 4623  kmem_slab_is_reclaimable(kmem_cache_t *cp, kmem_slab_t *sp, int flags)
4624 4624  {
4625 4625          long refcnt = sp->slab_refcnt;
4626 4626  
4627 4627          ASSERT(cp->cache_defrag != NULL);
4628 4628  
4629 4629          /*
4630 4630           * For code coverage we want to be able to move an object within the
4631 4631           * same slab (the only partial slab) even if allocating the destination
4632 4632           * buffer resulted in a completely allocated slab.
4633 4633           */
4634 4634          if (flags & KMM_DEBUG) {
4635 4635                  return ((flags & KMM_DESPERATE) ||
4636 4636                      ((sp->slab_flags & KMEM_SLAB_NOMOVE) == 0));
4637 4637          }
4638 4638  
4639 4639          /* If we're desperate, we don't care if the client said NO. */
4640 4640          if (flags & KMM_DESPERATE) {
4641 4641                  return (refcnt < sp->slab_chunks); /* any partial */
4642 4642          }
4643 4643  
4644 4644          if (sp->slab_flags & KMEM_SLAB_NOMOVE) {
4645 4645                  return (B_FALSE);
4646 4646          }
4647 4647  
4648 4648          if ((refcnt == 1) || kmem_move_any_partial) {
4649 4649                  return (refcnt < sp->slab_chunks);
4650 4650          }
4651 4651  
4652 4652          /*
4653 4653           * The reclaim threshold is adjusted at each kmem_cache_scan() so that
4654 4654           * slabs with a progressively higher percentage of used buffers can be
4655 4655           * reclaimed until the cache as a whole is no longer fragmented.
4656 4656           *
4657 4657           *      sp->slab_refcnt   kmd_reclaim_numer
4658 4658           *      --------------- < ------------------
4659 4659           *      sp->slab_chunks   KMEM_VOID_FRACTION
4660 4660           */
4661 4661          return ((refcnt * KMEM_VOID_FRACTION) <
4662 4662              (sp->slab_chunks * cp->cache_defrag->kmd_reclaim_numer));
4663 4663  }
4664 4664  
4665 4665  /*
4666 4666   * May be called from the kmem_move_taskq, from kmem_cache_move_notify_task(),
4667 4667   * or when the buffer is freed.
4668 4668   */
4669 4669  static void
4670 4670  kmem_slab_move_yes(kmem_cache_t *cp, kmem_slab_t *sp, void *from_buf)
4671 4671  {
4672 4672          ASSERT(MUTEX_HELD(&cp->cache_lock));
4673 4673          ASSERT(KMEM_SLAB_MEMBER(sp, from_buf));
4674 4674  
4675 4675          if (!KMEM_SLAB_IS_PARTIAL(sp)) {
4676 4676                  return;
4677 4677          }
4678 4678  
4679 4679          if (sp->slab_flags & KMEM_SLAB_NOMOVE) {
4680 4680                  if (KMEM_SLAB_OFFSET(sp, from_buf) == sp->slab_stuck_offset) {
4681 4681                          avl_remove(&cp->cache_partial_slabs, sp);
4682 4682                          sp->slab_flags &= ~KMEM_SLAB_NOMOVE;
4683 4683                          sp->slab_stuck_offset = (uint32_t)-1;
4684 4684                          avl_add(&cp->cache_partial_slabs, sp);
4685 4685                  }
4686 4686          } else {
4687 4687                  sp->slab_later_count = 0;
4688 4688                  sp->slab_stuck_offset = (uint32_t)-1;
4689 4689          }
4690 4690  }
4691 4691  
4692 4692  static void
4693 4693  kmem_slab_move_no(kmem_cache_t *cp, kmem_slab_t *sp, void *from_buf)
4694 4694  {
4695 4695          ASSERT(taskq_member(kmem_move_taskq, curthread));
4696 4696          ASSERT(MUTEX_HELD(&cp->cache_lock));
4697 4697          ASSERT(KMEM_SLAB_MEMBER(sp, from_buf));
4698 4698  
4699 4699          if (!KMEM_SLAB_IS_PARTIAL(sp)) {
4700 4700                  return;
4701 4701          }
4702 4702  
4703 4703          avl_remove(&cp->cache_partial_slabs, sp);
4704 4704          sp->slab_later_count = 0;
4705 4705          sp->slab_flags |= KMEM_SLAB_NOMOVE;
4706 4706          sp->slab_stuck_offset = KMEM_SLAB_OFFSET(sp, from_buf);
4707 4707          avl_add(&cp->cache_partial_slabs, sp);
4708 4708  }
4709 4709  
4710 4710  static void kmem_move_end(kmem_cache_t *, kmem_move_t *);
4711 4711  
4712 4712  /*
4713 4713   * The move callback takes two buffer addresses, the buffer to be moved, and a
4714 4714   * newly allocated and constructed buffer selected by kmem as the destination.
4715 4715   * It also takes the size of the buffer and an optional user argument specified
4716 4716   * at cache creation time. kmem guarantees that the buffer to be moved has not
4717 4717   * been unmapped by the virtual memory subsystem. Beyond that, it cannot
4718 4718   * guarantee the present whereabouts of the buffer to be moved, so it is up to
4719 4719   * the client to safely determine whether or not it is still using the buffer.
4720 4720   * The client must not free either of the buffers passed to the move callback,
4721 4721   * since kmem wants to free them directly to the slab layer. The client response
4722 4722   * tells kmem which of the two buffers to free:
4723 4723   *
4724 4724   * YES          kmem frees the old buffer (the move was successful)
4725 4725   * NO           kmem frees the new buffer, marks the slab of the old buffer
4726 4726   *              non-reclaimable to avoid bothering the client again
4727 4727   * LATER        kmem frees the new buffer, increments slab_later_count
4728 4728   * DONT_KNOW    kmem frees the new buffer
4729 4729   * DONT_NEED    kmem frees both the old buffer and the new buffer
4730 4730   *
4731 4731   * The pending callback argument now being processed contains both of the
4732 4732   * buffers (old and new) passed to the move callback function, the slab of the
4733 4733   * old buffer, and flags related to the move request, such as whether or not the
4734 4734   * system was desperate for memory.
4735 4735   *
4736 4736   * Slabs are not freed while there is a pending callback, but instead are kept
4737 4737   * on a deadlist, which is drained after the last callback completes. This means
4738 4738   * that slabs are safe to access until kmem_move_end(), no matter how many of
4739 4739   * their buffers have been freed. Once slab_refcnt reaches zero, it stays at
4740 4740   * zero for as long as the slab remains on the deadlist and until the slab is
4741 4741   * freed.
4742 4742   */
4743 4743  static void
4744 4744  kmem_move_buffer(kmem_move_t *callback)
4745 4745  {
4746 4746          kmem_cbrc_t response;
4747 4747          kmem_slab_t *sp = callback->kmm_from_slab;
4748 4748          kmem_cache_t *cp = sp->slab_cache;
4749 4749          boolean_t free_on_slab;
4750 4750  
4751 4751          ASSERT(taskq_member(kmem_move_taskq, curthread));
4752 4752          ASSERT(MUTEX_NOT_HELD(&cp->cache_lock));
4753 4753          ASSERT(KMEM_SLAB_MEMBER(sp, callback->kmm_from_buf));
4754 4754  
4755 4755          /*
4756 4756           * The number of allocated buffers on the slab may have changed since we
4757 4757           * last checked the slab's reclaimability (when the pending move was
4758 4758           * enqueued), or the client may have responded NO when asked to move
4759 4759           * another buffer on the same slab.
4760 4760           */
4761 4761          if (!kmem_slab_is_reclaimable(cp, sp, callback->kmm_flags)) {
4762 4762                  kmem_slab_free(cp, callback->kmm_to_buf);
4763 4763                  kmem_move_end(cp, callback);
4764 4764                  return;
4765 4765          }
4766 4766  
4767 4767          /*
4768 4768           * Checking the slab layer is easy, so we might as well do that here
4769 4769           * in case we can avoid bothering the client.
4770 4770           */
4771 4771          mutex_enter(&cp->cache_lock);
4772 4772          free_on_slab = (kmem_slab_allocated(cp, sp,
4773 4773              callback->kmm_from_buf) == NULL);
4774 4774          mutex_exit(&cp->cache_lock);
4775 4775  
4776 4776          if (free_on_slab) {
4777 4777                  kmem_slab_free(cp, callback->kmm_to_buf);
4778 4778                  kmem_move_end(cp, callback);
4779 4779                  return;
4780 4780          }
4781 4781  
4782 4782          if (cp->cache_flags & KMF_BUFTAG) {
4783 4783                  /*
4784 4784                   * Make kmem_cache_alloc_debug() apply the constructor for us.
4785 4785                   */
4786 4786                  if (kmem_cache_alloc_debug(cp, callback->kmm_to_buf,
4787 4787                      KM_NOSLEEP, 1, caller()) != 0) {
4788 4788                          kmem_move_end(cp, callback);
4789 4789                          return;
4790 4790                  }
4791 4791          } else if (cp->cache_constructor != NULL &&
4792 4792              cp->cache_constructor(callback->kmm_to_buf, cp->cache_private,
4793 4793              KM_NOSLEEP) != 0) {
4794 4794                  atomic_inc_64(&cp->cache_alloc_fail);
4795 4795                  kmem_slab_free(cp, callback->kmm_to_buf);
4796 4796                  kmem_move_end(cp, callback);
4797 4797                  return;
4798 4798          }
4799 4799  
4800 4800          cp->cache_defrag->kmd_callbacks++;
4801 4801          cp->cache_defrag->kmd_thread = curthread;
4802 4802          cp->cache_defrag->kmd_from_buf = callback->kmm_from_buf;
4803 4803          cp->cache_defrag->kmd_to_buf = callback->kmm_to_buf;
4804 4804          DTRACE_PROBE2(kmem__move__start, kmem_cache_t *, cp, kmem_move_t *,
4805 4805              callback);
4806 4806  
4807 4807          response = cp->cache_move(callback->kmm_from_buf,
4808 4808              callback->kmm_to_buf, cp->cache_bufsize, cp->cache_private);
4809 4809  
4810 4810          DTRACE_PROBE3(kmem__move__end, kmem_cache_t *, cp, kmem_move_t *,
4811 4811              callback, kmem_cbrc_t, response);
4812 4812          cp->cache_defrag->kmd_thread = NULL;
4813 4813          cp->cache_defrag->kmd_from_buf = NULL;
4814 4814          cp->cache_defrag->kmd_to_buf = NULL;
4815 4815  
4816 4816          if (response == KMEM_CBRC_YES) {
4817 4817                  cp->cache_defrag->kmd_yes++;
4818 4818                  kmem_slab_free_constructed(cp, callback->kmm_from_buf, B_FALSE);
4819 4819                  /* slab safe to access until kmem_move_end() */
4820 4820                  if (sp->slab_refcnt == 0)
4821 4821                          cp->cache_defrag->kmd_slabs_freed++;
4822 4822                  mutex_enter(&cp->cache_lock);
4823 4823                  kmem_slab_move_yes(cp, sp, callback->kmm_from_buf);
4824 4824                  mutex_exit(&cp->cache_lock);
4825 4825                  kmem_move_end(cp, callback);
4826 4826                  return;
4827 4827          }
4828 4828  
4829 4829          switch (response) {
4830 4830          case KMEM_CBRC_NO:
4831 4831                  cp->cache_defrag->kmd_no++;
4832 4832                  mutex_enter(&cp->cache_lock);
4833 4833                  kmem_slab_move_no(cp, sp, callback->kmm_from_buf);
4834 4834                  mutex_exit(&cp->cache_lock);
4835 4835                  break;
4836 4836          case KMEM_CBRC_LATER:
4837 4837                  cp->cache_defrag->kmd_later++;
4838 4838                  mutex_enter(&cp->cache_lock);
4839 4839                  if (!KMEM_SLAB_IS_PARTIAL(sp)) {
4840 4840                          mutex_exit(&cp->cache_lock);
4841 4841                          break;
4842 4842                  }
4843 4843  
4844 4844                  if (++sp->slab_later_count >= KMEM_DISBELIEF) {
4845 4845                          kmem_slab_move_no(cp, sp, callback->kmm_from_buf);
4846 4846                  } else if (!(sp->slab_flags & KMEM_SLAB_NOMOVE)) {
4847 4847                          sp->slab_stuck_offset = KMEM_SLAB_OFFSET(sp,
4848 4848                              callback->kmm_from_buf);
4849 4849                  }
4850 4850                  mutex_exit(&cp->cache_lock);
4851 4851                  break;
4852 4852          case KMEM_CBRC_DONT_NEED:
4853 4853                  cp->cache_defrag->kmd_dont_need++;
4854 4854                  kmem_slab_free_constructed(cp, callback->kmm_from_buf, B_FALSE);
4855 4855                  if (sp->slab_refcnt == 0)
4856 4856                          cp->cache_defrag->kmd_slabs_freed++;
4857 4857                  mutex_enter(&cp->cache_lock);
4858 4858                  kmem_slab_move_yes(cp, sp, callback->kmm_from_buf);
4859 4859                  mutex_exit(&cp->cache_lock);
4860 4860                  break;
4861 4861          case KMEM_CBRC_DONT_KNOW:
4862 4862                  /*
4863 4863                   * If we don't know if we can move this buffer or not, we'll
4864 4864                   * just assume that we can't:  if the buffer is in fact free,
4865 4865                   * then it is sitting in one of the per-CPU magazines or in
4866 4866                   * a full magazine in the depot layer.  Either way, because
4867 4867                   * defrag is induced in the same logic that reaps a cache,
4868 4868                   * it's likely that full magazines will be returned to the
4869 4869                   * system soon (thereby accomplishing what we're trying to
4870 4870                   * accomplish here: return those magazines to their slabs).
4871 4871                   * Given this, any work that we might do now to locate a buffer
4872 4872                   * in a magazine is wasted (and expensive!) work; we bump
4873 4873                   * a counter in this case and otherwise assume that we can't
4874 4874                   * move it.
4875 4875                   */
4876 4876                  cp->cache_defrag->kmd_dont_know++;
4877 4877                  break;
4878 4878          default:
4879 4879                  panic("'%s' (%p) unexpected move callback response %d\n",
4880 4880                      cp->cache_name, (void *)cp, response);
4881 4881          }
4882 4882  
4883 4883          kmem_slab_free_constructed(cp, callback->kmm_to_buf, B_FALSE);
4884 4884          kmem_move_end(cp, callback);
4885 4885  }
4886 4886  
4887 4887  /* Return B_FALSE if there is insufficient memory for the move request. */
4888 4888  static boolean_t
4889 4889  kmem_move_begin(kmem_cache_t *cp, kmem_slab_t *sp, void *buf, int flags)
4890 4890  {
4891 4891          void *to_buf;
4892 4892          avl_index_t index;
4893 4893          kmem_move_t *callback, *pending;
4894 4894          ulong_t n;
4895 4895  
4896 4896          ASSERT(taskq_member(kmem_taskq, curthread));
4897 4897          ASSERT(MUTEX_NOT_HELD(&cp->cache_lock));
4898 4898          ASSERT(sp->slab_flags & KMEM_SLAB_MOVE_PENDING);
4899 4899  
4900 4900          callback = kmem_cache_alloc(kmem_move_cache, KM_NOSLEEP);
4901 4901  
4902 4902          if (callback == NULL)
4903 4903                  return (B_FALSE);
4904 4904  
4905 4905          callback->kmm_from_slab = sp;
4906 4906          callback->kmm_from_buf = buf;
4907 4907          callback->kmm_flags = flags;
4908 4908  
4909 4909          mutex_enter(&cp->cache_lock);
4910 4910  
4911 4911          n = avl_numnodes(&cp->cache_partial_slabs);
4912 4912          if ((n == 0) || ((n == 1) && !(flags & KMM_DEBUG))) {
4913 4913                  mutex_exit(&cp->cache_lock);
4914 4914                  kmem_cache_free(kmem_move_cache, callback);
4915 4915                  return (B_TRUE); /* there is no need for the move request */
4916 4916          }
4917 4917  
4918 4918          pending = avl_find(&cp->cache_defrag->kmd_moves_pending, buf, &index);
4919 4919          if (pending != NULL) {
4920 4920                  /*
4921 4921                   * If the move is already pending and we're desperate now,
4922 4922                   * update the move flags.
4923 4923                   */
4924 4924                  if (flags & KMM_DESPERATE) {
4925 4925                          pending->kmm_flags |= KMM_DESPERATE;
4926 4926                  }
4927 4927                  mutex_exit(&cp->cache_lock);
4928 4928                  kmem_cache_free(kmem_move_cache, callback);
4929 4929                  return (B_TRUE);
4930 4930          }
4931 4931  
4932 4932          to_buf = kmem_slab_alloc_impl(cp, avl_first(&cp->cache_partial_slabs),
4933 4933              B_FALSE);
4934 4934          callback->kmm_to_buf = to_buf;
4935 4935          avl_insert(&cp->cache_defrag->kmd_moves_pending, callback, index);
4936 4936  
4937 4937          mutex_exit(&cp->cache_lock);
4938 4938  
4939 4939          if (taskq_dispatch(kmem_move_taskq, (task_func_t *)kmem_move_buffer,
4940 4940              callback, TQ_NOSLEEP) == TASKQID_INVALID) {
4941 4941                  mutex_enter(&cp->cache_lock);
4942 4942                  avl_remove(&cp->cache_defrag->kmd_moves_pending, callback);
4943 4943                  mutex_exit(&cp->cache_lock);
4944 4944                  kmem_slab_free(cp, to_buf);
4945 4945                  kmem_cache_free(kmem_move_cache, callback);
4946 4946                  return (B_FALSE);
4947 4947          }
4948 4948  
4949 4949          return (B_TRUE);
4950 4950  }
4951 4951  
4952 4952  static void
4953 4953  kmem_move_end(kmem_cache_t *cp, kmem_move_t *callback)
4954 4954  {
4955 4955          avl_index_t index;
4956 4956  
4957 4957          ASSERT(cp->cache_defrag != NULL);
4958 4958          ASSERT(taskq_member(kmem_move_taskq, curthread));
4959 4959          ASSERT(MUTEX_NOT_HELD(&cp->cache_lock));
4960 4960  
4961 4961          mutex_enter(&cp->cache_lock);
4962 4962          VERIFY(avl_find(&cp->cache_defrag->kmd_moves_pending,
4963 4963              callback->kmm_from_buf, &index) != NULL);
4964 4964          avl_remove(&cp->cache_defrag->kmd_moves_pending, callback);
4965 4965          if (avl_is_empty(&cp->cache_defrag->kmd_moves_pending)) {
4966 4966                  list_t *deadlist = &cp->cache_defrag->kmd_deadlist;
4967 4967                  kmem_slab_t *sp;
4968 4968  
4969 4969                  /*
4970 4970                   * The last pending move completed. Release all slabs from the
4971 4971                   * front of the dead list except for any slab at the tail that
4972 4972                   * needs to be released from the context of kmem_move_buffers().
4973 4973                   * kmem deferred unmapping the buffers on these slabs in order
4974 4974                   * to guarantee that buffers passed to the move callback have
4975 4975                   * been touched only by kmem or by the client itself.
4976 4976                   */
4977 4977                  while ((sp = list_remove_head(deadlist)) != NULL) {
4978 4978                          if (sp->slab_flags & KMEM_SLAB_MOVE_PENDING) {
4979 4979                                  list_insert_tail(deadlist, sp);
4980 4980                                  break;
4981 4981                          }
4982 4982                          cp->cache_defrag->kmd_deadcount--;
4983 4983                          cp->cache_slab_destroy++;
4984 4984                          mutex_exit(&cp->cache_lock);
4985 4985                          kmem_slab_destroy(cp, sp);
4986 4986                          mutex_enter(&cp->cache_lock);
4987 4987                  }
4988 4988          }
4989 4989          mutex_exit(&cp->cache_lock);
4990 4990          kmem_cache_free(kmem_move_cache, callback);
4991 4991  }
4992 4992  
4993 4993  /*
4994 4994   * Move buffers from least used slabs first by scanning backwards from the end
4995 4995   * of the partial slab list. Scan at most max_scan candidate slabs and move
4996 4996   * buffers from at most max_slabs slabs (0 for all partial slabs in both cases).
4997 4997   * If desperate to reclaim memory, move buffers from any partial slab, otherwise
4998 4998   * skip slabs with a ratio of allocated buffers at or above the current
4999 4999   * threshold. Return the number of unskipped slabs (at most max_slabs, -1 if the
5000 5000   * scan is aborted) so that the caller can adjust the reclaimability threshold
5001 5001   * depending on how many reclaimable slabs it finds.
5002 5002   *
5003 5003   * kmem_move_buffers() drops and reacquires cache_lock every time it issues a
5004 5004   * move request, since it is not valid for kmem_move_begin() to call
5005 5005   * kmem_cache_alloc() or taskq_dispatch() with cache_lock held.
5006 5006   */
5007 5007  static int
5008 5008  kmem_move_buffers(kmem_cache_t *cp, size_t max_scan, size_t max_slabs,
5009 5009      int flags)
5010 5010  {
5011 5011          kmem_slab_t *sp;
5012 5012          void *buf;
5013 5013          int i, j; /* slab index, buffer index */
5014 5014          int s; /* reclaimable slabs */
5015 5015          int b; /* allocated (movable) buffers on reclaimable slab */
5016 5016          boolean_t success;
5017 5017          int refcnt;
5018 5018          int nomove;
5019 5019  
5020 5020          ASSERT(taskq_member(kmem_taskq, curthread));
5021 5021          ASSERT(MUTEX_HELD(&cp->cache_lock));
5022 5022          ASSERT(kmem_move_cache != NULL);
5023 5023          ASSERT(cp->cache_move != NULL && cp->cache_defrag != NULL);
5024 5024          ASSERT((flags & KMM_DEBUG) ? !avl_is_empty(&cp->cache_partial_slabs) :
5025 5025              avl_numnodes(&cp->cache_partial_slabs) > 1);
5026 5026  
5027 5027          if (kmem_move_blocked) {
5028 5028                  return (0);
5029 5029          }
5030 5030  
5031 5031          if (kmem_move_fulltilt) {
5032 5032                  flags |= KMM_DESPERATE;
5033 5033          }
5034 5034  
5035 5035          if (max_scan == 0 || (flags & KMM_DESPERATE)) {
5036 5036                  /*
5037 5037                   * Scan as many slabs as needed to find the desired number of
5038 5038                   * candidate slabs.
5039 5039                   */
5040 5040                  max_scan = (size_t)-1;
5041 5041          }
5042 5042  
5043 5043          if (max_slabs == 0 || (flags & KMM_DESPERATE)) {
5044 5044                  /* Find as many candidate slabs as possible. */
5045 5045                  max_slabs = (size_t)-1;
5046 5046          }
5047 5047  
5048 5048          sp = avl_last(&cp->cache_partial_slabs);
5049 5049          ASSERT(KMEM_SLAB_IS_PARTIAL(sp));
5050 5050          for (i = 0, s = 0; (i < max_scan) && (s < max_slabs) && (sp != NULL) &&
5051 5051              ((sp != avl_first(&cp->cache_partial_slabs)) ||
5052 5052              (flags & KMM_DEBUG));
5053 5053              sp = AVL_PREV(&cp->cache_partial_slabs, sp), i++) {
5054 5054  
5055 5055                  if (!kmem_slab_is_reclaimable(cp, sp, flags)) {
5056 5056                          continue;
5057 5057                  }
5058 5058                  s++;
5059 5059  
5060 5060                  /* Look for allocated buffers to move. */
5061 5061                  for (j = 0, b = 0, buf = sp->slab_base;
5062 5062                      (j < sp->slab_chunks) && (b < sp->slab_refcnt);
5063 5063                      buf = (((char *)buf) + cp->cache_chunksize), j++) {
5064 5064  
5065 5065                          if (kmem_slab_allocated(cp, sp, buf) == NULL) {
5066 5066                                  continue;
5067 5067                          }
5068 5068  
5069 5069                          b++;
5070 5070  
5071 5071                          /*
5072 5072                           * Prevent the slab from being destroyed while we drop
5073 5073                           * cache_lock and while the pending move is not yet
5074 5074                           * registered. Flag the pending move while
5075 5075                           * kmd_moves_pending may still be empty, since we can't
5076 5076                           * yet rely on a non-zero pending move count to prevent
5077 5077                           * the slab from being destroyed.
5078 5078                           */
5079 5079                          ASSERT(!(sp->slab_flags & KMEM_SLAB_MOVE_PENDING));
5080 5080                          sp->slab_flags |= KMEM_SLAB_MOVE_PENDING;
5081 5081                          /*
5082 5082                           * Recheck refcnt and nomove after reacquiring the lock,
5083 5083                           * since these control the order of partial slabs, and
5084 5084                           * we want to know if we can pick up the scan where we
5085 5085                           * left off.
5086 5086                           */
5087 5087                          refcnt = sp->slab_refcnt;
5088 5088                          nomove = (sp->slab_flags & KMEM_SLAB_NOMOVE);
5089 5089                          mutex_exit(&cp->cache_lock);
5090 5090  
5091 5091                          success = kmem_move_begin(cp, sp, buf, flags);
5092 5092  
5093 5093                          /*
5094 5094                           * Now, before the lock is reacquired, kmem could
5095 5095                           * process all pending move requests and purge the
5096 5096                           * deadlist, so that upon reacquiring the lock, sp has
5097 5097                           * been remapped. Or, the client may free all the
5098 5098                           * objects on the slab while the pending moves are still
5099 5099                           * on the taskq. Therefore, the KMEM_SLAB_MOVE_PENDING
5100 5100                           * flag causes the slab to be put at the end of the
5101 5101                           * deadlist and prevents it from being destroyed, since
5102 5102                           * we plan to destroy it here after reacquiring the
5103 5103                           * lock.
5104 5104                           */
5105 5105                          mutex_enter(&cp->cache_lock);
5106 5106                          ASSERT(sp->slab_flags & KMEM_SLAB_MOVE_PENDING);
5107 5107                          sp->slab_flags &= ~KMEM_SLAB_MOVE_PENDING;
5108 5108  
5109 5109                          if (sp->slab_refcnt == 0) {
5110 5110                                  list_t *deadlist =
5111 5111                                      &cp->cache_defrag->kmd_deadlist;
5112 5112                                  list_remove(deadlist, sp);
5113 5113  
5114 5114                                  if (!avl_is_empty(
5115 5115                                      &cp->cache_defrag->kmd_moves_pending)) {
5116 5116                                          /*
5117 5117                                           * A pending move makes it unsafe to
5118 5118                                           * destroy the slab, because even though
5119 5119                                           * the move is no longer needed, the
5120 5120                                           * context where that is determined
5121 5121                                           * requires the slab to exist.
5122 5122                                           * Fortunately, a pending move also
5123 5123                                           * means we don't need to destroy the
5124 5124                                           * slab here, since it will get
5125 5125                                           * destroyed along with any other slabs
5126 5126                                           * on the deadlist after the last
5127 5127                                           * pending move completes.
5128 5128                                           */
5129 5129                                          list_insert_head(deadlist, sp);
5130 5130                                          return (-1);
5131 5131                                  }
5132 5132  
5133 5133                                  /*
5134 5134                                   * Destroy the slab now if it was completely
5135 5135                                   * freed while we dropped cache_lock and there
5136 5136                                   * are no pending moves. Since slab_refcnt
5137 5137                                   * cannot change once it reaches zero, no new
5138 5138                                   * pending moves from that slab are possible.
5139 5139                                   */
5140 5140                                  cp->cache_defrag->kmd_deadcount--;
5141 5141                                  cp->cache_slab_destroy++;
5142 5142                                  mutex_exit(&cp->cache_lock);
5143 5143                                  kmem_slab_destroy(cp, sp);
5144 5144                                  mutex_enter(&cp->cache_lock);
5145 5145                                  /*
5146 5146                                   * Since we can't pick up the scan where we left
5147 5147                                   * off, abort the scan and say nothing about the
5148 5148                                   * number of reclaimable slabs.
5149 5149                                   */
5150 5150                                  return (-1);
5151 5151                          }
5152 5152  
5153 5153                          if (!success) {
5154 5154                                  /*
5155 5155                                   * Abort the scan if there is not enough memory
5156 5156                                   * for the request and say nothing about the
5157 5157                                   * number of reclaimable slabs.
5158 5158                                   */
5159 5159                                  return (-1);
5160 5160                          }
5161 5161  
5162 5162                          /*
5163 5163                           * The slab's position changed while the lock was
5164 5164                           * dropped, so we don't know where we are in the
5165 5165                           * sequence any more.
5166 5166                           */
5167 5167                          if (sp->slab_refcnt != refcnt) {
5168 5168                                  /*
5169 5169                                   * If this is a KMM_DEBUG move, the slab_refcnt
5170 5170                                   * may have changed because we allocated a
5171 5171                                   * destination buffer on the same slab. In that
5172 5172                                   * case, we're not interested in counting it.
5173 5173                                   */
5174 5174                                  return (-1);
5175 5175                          }
5176 5176                          if ((sp->slab_flags & KMEM_SLAB_NOMOVE) != nomove)
5177 5177                                  return (-1);
5178 5178  
5179 5179                          /*
5180 5180                           * Generating a move request allocates a destination
5181 5181                           * buffer from the slab layer, bumping the first partial
5182 5182                           * slab if it is completely allocated. If the current
5183 5183                           * slab becomes the first partial slab as a result, we
5184 5184                           * can't continue to scan backwards.
5185 5185                           *
5186 5186                           * If this is a KMM_DEBUG move and we allocated the
5187 5187                           * destination buffer from the last partial slab, then
5188 5188                           * the buffer we're moving is on the same slab and our
5189 5189                           * slab_refcnt has changed, causing us to return before
5190 5190                           * reaching here if there are no partial slabs left.
5191 5191                           */
5192 5192                          ASSERT(!avl_is_empty(&cp->cache_partial_slabs));
5193 5193                          if (sp == avl_first(&cp->cache_partial_slabs)) {
5194 5194                                  /*
5195 5195                                   * We're not interested in a second KMM_DEBUG
5196 5196                                   * move.
5197 5197                                   */
5198 5198                                  goto end_scan;
5199 5199                          }
5200 5200                  }
5201 5201          }
5202 5202  end_scan:
5203 5203  
5204 5204          return (s);
5205 5205  }
5206 5206  
5207 5207  typedef struct kmem_move_notify_args {
5208 5208          kmem_cache_t *kmna_cache;
5209 5209          void *kmna_buf;
5210 5210  } kmem_move_notify_args_t;
5211 5211  
5212 5212  static void
5213 5213  kmem_cache_move_notify_task(void *arg)
5214 5214  {
5215 5215          kmem_move_notify_args_t *args = arg;
5216 5216          kmem_cache_t *cp = args->kmna_cache;
5217 5217          void *buf = args->kmna_buf;
5218 5218          kmem_slab_t *sp;
5219 5219  
5220 5220          ASSERT(taskq_member(kmem_taskq, curthread));
5221 5221          ASSERT(list_link_active(&cp->cache_link));
5222 5222  
5223 5223          kmem_free(args, sizeof (kmem_move_notify_args_t));
5224 5224          mutex_enter(&cp->cache_lock);
5225 5225          sp = kmem_slab_allocated(cp, NULL, buf);
5226 5226  
5227 5227          /* Ignore the notification if the buffer is no longer allocated. */
5228 5228          if (sp == NULL) {
5229 5229                  mutex_exit(&cp->cache_lock);
5230 5230                  return;
5231 5231          }
5232 5232  
5233 5233          /* Ignore the notification if there's no reason to move the buffer. */
5234 5234          if (avl_numnodes(&cp->cache_partial_slabs) > 1) {
5235 5235                  /*
5236 5236                   * So far the notification is not ignored. Ignore the
5237 5237                   * notification if the slab is not marked by an earlier refusal
5238 5238                   * to move a buffer.
5239 5239                   */
5240 5240                  if (!(sp->slab_flags & KMEM_SLAB_NOMOVE) &&
5241 5241                      (sp->slab_later_count == 0)) {
5242 5242                          mutex_exit(&cp->cache_lock);
5243 5243                          return;
5244 5244                  }
5245 5245  
5246 5246                  kmem_slab_move_yes(cp, sp, buf);
5247 5247                  ASSERT(!(sp->slab_flags & KMEM_SLAB_MOVE_PENDING));
5248 5248                  sp->slab_flags |= KMEM_SLAB_MOVE_PENDING;
5249 5249                  mutex_exit(&cp->cache_lock);
5250 5250                  /* see kmem_move_buffers() about dropping the lock */
5251 5251                  (void) kmem_move_begin(cp, sp, buf, KMM_NOTIFY);
5252 5252                  mutex_enter(&cp->cache_lock);
5253 5253                  ASSERT(sp->slab_flags & KMEM_SLAB_MOVE_PENDING);
5254 5254                  sp->slab_flags &= ~KMEM_SLAB_MOVE_PENDING;
5255 5255                  if (sp->slab_refcnt == 0) {
5256 5256                          list_t *deadlist = &cp->cache_defrag->kmd_deadlist;
5257 5257                          list_remove(deadlist, sp);
5258 5258  
5259 5259                          if (!avl_is_empty(
5260 5260                              &cp->cache_defrag->kmd_moves_pending)) {
5261 5261                                  list_insert_head(deadlist, sp);
5262 5262                                  mutex_exit(&cp->cache_lock);
5263 5263                                  return;
5264 5264                          }
5265 5265  
5266 5266                          cp->cache_defrag->kmd_deadcount--;
5267 5267                          cp->cache_slab_destroy++;
5268 5268                          mutex_exit(&cp->cache_lock);
5269 5269                          kmem_slab_destroy(cp, sp);
5270 5270                          return;
5271 5271                  }
5272 5272          } else {
5273 5273                  kmem_slab_move_yes(cp, sp, buf);
5274 5274          }
5275 5275          mutex_exit(&cp->cache_lock);
5276 5276  }
5277 5277  
5278 5278  void
5279 5279  kmem_cache_move_notify(kmem_cache_t *cp, void *buf)
5280 5280  {
5281 5281          kmem_move_notify_args_t *args;
5282 5282  
5283 5283          args = kmem_alloc(sizeof (kmem_move_notify_args_t), KM_NOSLEEP);
5284 5284          if (args != NULL) {
5285 5285                  args->kmna_cache = cp;
5286 5286                  args->kmna_buf = buf;
5287 5287                  if (taskq_dispatch(kmem_taskq,
5288 5288                      (task_func_t *)kmem_cache_move_notify_task, args,
5289 5289                      TQ_NOSLEEP) == TASKQID_INVALID)
5290 5290                          kmem_free(args, sizeof (kmem_move_notify_args_t));
5291 5291          }
5292 5292  }
5293 5293  
5294 5294  static void
5295 5295  kmem_cache_defrag(kmem_cache_t *cp)
5296 5296  {
5297 5297          size_t n;
5298 5298  
5299 5299          ASSERT(cp->cache_defrag != NULL);
5300 5300  
5301 5301          mutex_enter(&cp->cache_lock);
5302 5302          n = avl_numnodes(&cp->cache_partial_slabs);
5303 5303          if (n > 1) {
5304 5304                  /* kmem_move_buffers() drops and reacquires cache_lock */
5305 5305                  cp->cache_defrag->kmd_defrags++;
5306 5306                  (void) kmem_move_buffers(cp, n, 0, KMM_DESPERATE);
5307 5307          }
5308 5308          mutex_exit(&cp->cache_lock);
5309 5309  }
5310 5310  
5311 5311  /* Is this cache above the fragmentation threshold? */
5312 5312  static boolean_t
5313 5313  kmem_cache_frag_threshold(kmem_cache_t *cp, uint64_t nfree)
5314 5314  {
5315 5315          /*
5316 5316           *      nfree           kmem_frag_numer
5317 5317           * ------------------ > ---------------
5318 5318           * cp->cache_buftotal   kmem_frag_denom
5319 5319           */
5320 5320          return ((nfree * kmem_frag_denom) >
5321 5321              (cp->cache_buftotal * kmem_frag_numer));
5322 5322  }
5323 5323  
5324 5324  static boolean_t
5325 5325  kmem_cache_is_fragmented(kmem_cache_t *cp, boolean_t *doreap)
5326 5326  {
5327 5327          boolean_t fragmented;
5328 5328          uint64_t nfree;
5329 5329  
5330 5330          ASSERT(MUTEX_HELD(&cp->cache_lock));
5331 5331          *doreap = B_FALSE;
5332 5332  
5333 5333          if (kmem_move_fulltilt) {
5334 5334                  if (avl_numnodes(&cp->cache_partial_slabs) > 1) {
5335 5335                          return (B_TRUE);
5336 5336                  }
5337 5337          } else {
5338 5338                  if ((cp->cache_complete_slab_count + avl_numnodes(
5339 5339                      &cp->cache_partial_slabs)) < kmem_frag_minslabs) {
5340 5340                          return (B_FALSE);
5341 5341                  }
5342 5342          }
5343 5343  
5344 5344          nfree = cp->cache_bufslab;
5345 5345          fragmented = ((avl_numnodes(&cp->cache_partial_slabs) > 1) &&
5346 5346              kmem_cache_frag_threshold(cp, nfree));
5347 5347  
5348 5348          /*
5349 5349           * Free buffers in the magazine layer appear allocated from the point of
5350 5350           * view of the slab layer. We want to know if the slab layer would
5351 5351           * appear fragmented if we included free buffers from magazines that
5352 5352           * have fallen out of the working set.
5353 5353           */
5354 5354          if (!fragmented) {
5355 5355                  long reap;
5356 5356  
5357 5357                  mutex_enter(&cp->cache_depot_lock);
5358 5358                  reap = MIN(cp->cache_full.ml_reaplimit, cp->cache_full.ml_min);
5359 5359                  reap = MIN(reap, cp->cache_full.ml_total);
5360 5360                  mutex_exit(&cp->cache_depot_lock);
5361 5361  
5362 5362                  nfree += ((uint64_t)reap * cp->cache_magtype->mt_magsize);
5363 5363                  if (kmem_cache_frag_threshold(cp, nfree)) {
5364 5364                          *doreap = B_TRUE;
5365 5365                  }
5366 5366          }
5367 5367  
5368 5368          return (fragmented);
5369 5369  }
5370 5370  
5371 5371  /* Called periodically from kmem_taskq */
5372 5372  static void
5373 5373  kmem_cache_scan(kmem_cache_t *cp)
5374 5374  {
5375 5375          boolean_t reap = B_FALSE;
5376 5376          kmem_defrag_t *kmd;
5377 5377  
5378 5378          ASSERT(taskq_member(kmem_taskq, curthread));
5379 5379  
5380 5380          mutex_enter(&cp->cache_lock);
5381 5381  
5382 5382          kmd = cp->cache_defrag;
5383 5383          if (kmd->kmd_consolidate > 0) {
5384 5384                  kmd->kmd_consolidate--;
5385 5385                  mutex_exit(&cp->cache_lock);
5386 5386                  kmem_cache_reap(cp);
5387 5387                  return;
5388 5388          }
5389 5389  
5390 5390          if (kmem_cache_is_fragmented(cp, &reap)) {
5391 5391                  int slabs_found;
5392 5392  
5393 5393                  /*
5394 5394                   * Consolidate reclaimable slabs from the end of the partial
5395 5395                   * slab list (scan at most kmem_reclaim_scan_range slabs to find
5396 5396                   * reclaimable slabs). Keep track of how many candidate slabs we
5397 5397                   * looked for and how many we actually found so we can adjust
5398 5398                   * the definition of a candidate slab if we're having trouble
5399 5399                   * finding them.
5400 5400                   *
5401 5401                   * kmem_move_buffers() drops and reacquires cache_lock.
5402 5402                   */
5403 5403                  kmd->kmd_scans++;
5404 5404                  slabs_found = kmem_move_buffers(cp, kmem_reclaim_scan_range,
5405 5405                      kmem_reclaim_max_slabs, 0);
5406 5406                  if (slabs_found >= 0) {
5407 5407                          kmd->kmd_slabs_sought += kmem_reclaim_max_slabs;
5408 5408                          kmd->kmd_slabs_found += slabs_found;
5409 5409                  }
5410 5410  
5411 5411                  if (++kmd->kmd_tries >= kmem_reclaim_scan_range) {
5412 5412                          kmd->kmd_tries = 0;
5413 5413  
5414 5414                          /*
5415 5415                           * If we had difficulty finding candidate slabs in
5416 5416                           * previous scans, adjust the threshold so that
5417 5417                           * candidates are easier to find.
5418 5418                           */
5419 5419                          if (kmd->kmd_slabs_found == kmd->kmd_slabs_sought) {
5420 5420                                  kmem_adjust_reclaim_threshold(kmd, -1);
5421 5421                          } else if ((kmd->kmd_slabs_found * 2) <
5422 5422                              kmd->kmd_slabs_sought) {
5423 5423                                  kmem_adjust_reclaim_threshold(kmd, 1);
5424 5424                          }
5425 5425                          kmd->kmd_slabs_sought = 0;
5426 5426                          kmd->kmd_slabs_found = 0;
5427 5427                  }
5428 5428          } else {
5429 5429                  kmem_reset_reclaim_threshold(cp->cache_defrag);
5430 5430  #ifdef  DEBUG
5431 5431                  if (!avl_is_empty(&cp->cache_partial_slabs)) {
5432 5432                          /*
5433 5433                           * In a debug kernel we want the consolidator to
5434 5434                           * run occasionally even when there is plenty of
5435 5435                           * memory.
5436 5436                           */
5437 5437                          uint16_t debug_rand;
5438 5438  
5439 5439                          (void) random_get_bytes((uint8_t *)&debug_rand, 2);
5440 5440                          if (!kmem_move_noreap &&
5441 5441                              ((debug_rand % kmem_mtb_reap) == 0)) {
5442 5442                                  mutex_exit(&cp->cache_lock);
5443 5443                                  kmem_cache_reap(cp);
5444 5444                                  return;
5445 5445                          } else if ((debug_rand % kmem_mtb_move) == 0) {
5446 5446                                  kmd->kmd_scans++;
5447 5447                                  (void) kmem_move_buffers(cp,
5448 5448                                      kmem_reclaim_scan_range, 1, KMM_DEBUG);
5449 5449                          }
5450 5450                  }
5451 5451  #endif  /* DEBUG */
5452 5452          }
5453 5453  
5454 5454          mutex_exit(&cp->cache_lock);
5455 5455  
5456 5456          if (reap)
5457 5457                  kmem_depot_ws_reap(cp);
5458 5458  }

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX