OS-6363 system went to dark side of moon for ~467 seconds OS-6404 ARC reclaim should throttle its calls to arc_kmem_reap_now() Reviewed by: Bryan Cantrill <bryan@joyent.com> Reviewed by: Dan McDonald <danmcd@joyent.com>

*** 20,30 ****
   */
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
   * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
!  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
   */
  
  #ifndef _SYS_ZFS_CONTEXT_H
  #define _SYS_ZFS_CONTEXT_H
  
--- 20,30 ----
   */
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
   * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
!  * Copyright (c) 2017, Joyent, Inc. All rights reserved.
   */
  
  #ifndef _SYS_ZFS_CONTEXT_H
  #define _SYS_ZFS_CONTEXT_H
  
*** 331,341 ****
          umem_cache_create(_a, _b, _c, _d, _e, _f, _g, _h, _i)
  #define kmem_cache_destroy(_c)  umem_cache_destroy(_c)
  #define kmem_cache_alloc(_c, _f) umem_cache_alloc(_c, _f)
  #define kmem_cache_free(_c, _b) umem_cache_free(_c, _b)
  #define kmem_debugging()        0
! #define kmem_cache_reap_now(_c)         /* nothing */
  #define kmem_cache_set_move(_c, _cb)    /* nothing */
  #define vmem_qcache_reap(_v)            /* nothing */
  #define POINTER_INVALIDATE(_pp)         /* nothing */
  #define POINTER_IS_VALID(_p)    0
  
--- 331,342 ----
          umem_cache_create(_a, _b, _c, _d, _e, _f, _g, _h, _i)
  #define kmem_cache_destroy(_c)  umem_cache_destroy(_c)
  #define kmem_cache_alloc(_c, _f) umem_cache_alloc(_c, _f)
  #define kmem_cache_free(_c, _b) umem_cache_free(_c, _b)
  #define kmem_debugging()        0
! #define kmem_cache_reap_active()        (B_FALSE)
! #define kmem_cache_reap_soon(_c)        /* nothing */
  #define kmem_cache_set_move(_c, _cb)    /* nothing */
  #define vmem_qcache_reap(_v)            /* nothing */
  #define POINTER_INVALIDATE(_pp)         /* nothing */
  #define POINTER_IS_VALID(_p)    0
  
*** 389,398 ****
--- 390,400 ----
              (taskq_create(a, b, maxclsyspri, d, e, f))
  extern taskqid_t taskq_dispatch(taskq_t *, task_func_t, void *, uint_t);
  extern void     taskq_dispatch_ent(taskq_t *, task_func_t, void *, uint_t,
      taskq_ent_t *);
  extern void     taskq_destroy(taskq_t *);
+ extern boolean_t taskq_empty(taskq_t *);
  extern void     taskq_wait(taskq_t *);
  extern int      taskq_member(taskq_t *, void *);
  extern void     system_taskq_init(void);
  extern void     system_taskq_fini(void);