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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>
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--- old/usr/src/lib/libzpool/common/taskq.c
+++ new/usr/src/lib/libzpool/common/taskq.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 *
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19 19 * CDDL HEADER END
20 20 */
21 21 /*
22 22 * Copyright 2010 Sun Microsystems, Inc. All rights reserved.
23 23 * Use is subject to license terms.
24 24 */
25 25 /*
26 26 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
27 27 * Copyright 2012 Garrett D'Amore <garrett@damore.org>. All rights reserved.
28 28 * Copyright (c) 2014 by Delphix. All rights reserved.
29 + * Copyright (c) 2017, Joyent, Inc.
29 30 */
30 31
31 32 #include <sys/zfs_context.h>
32 33
33 34 int taskq_now;
34 35 taskq_t *system_taskq;
35 36
36 37 #define TASKQ_ACTIVE 0x00010000
37 38 #define TASKQ_NAMELEN 31
38 39
39 40 struct taskq {
40 41 char tq_name[TASKQ_NAMELEN + 1];
41 42 kmutex_t tq_lock;
42 43 krwlock_t tq_threadlock;
43 44 kcondvar_t tq_dispatch_cv;
44 45 kcondvar_t tq_wait_cv;
45 46 thread_t *tq_threadlist;
46 47 int tq_flags;
47 48 int tq_active;
48 49 int tq_nthreads;
49 50 int tq_nalloc;
50 51 int tq_minalloc;
51 52 int tq_maxalloc;
52 53 kcondvar_t tq_maxalloc_cv;
53 54 int tq_maxalloc_wait;
54 55 taskq_ent_t *tq_freelist;
55 56 taskq_ent_t tq_task;
56 57 };
57 58
58 59 static taskq_ent_t *
59 60 task_alloc(taskq_t *tq, int tqflags)
60 61 {
61 62 taskq_ent_t *t;
62 63 int rv;
63 64
64 65 again: if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
65 66 tq->tq_freelist = t->tqent_next;
66 67 } else {
67 68 if (tq->tq_nalloc >= tq->tq_maxalloc) {
68 69 if (!(tqflags & KM_SLEEP))
69 70 return (NULL);
70 71
71 72 /*
72 73 * We don't want to exceed tq_maxalloc, but we can't
73 74 * wait for other tasks to complete (and thus free up
74 75 * task structures) without risking deadlock with
75 76 * the caller. So, we just delay for one second
76 77 * to throttle the allocation rate. If we have tasks
77 78 * complete before one second timeout expires then
78 79 * taskq_ent_free will signal us and we will
79 80 * immediately retry the allocation.
80 81 */
81 82 tq->tq_maxalloc_wait++;
82 83 rv = cv_timedwait(&tq->tq_maxalloc_cv,
83 84 &tq->tq_lock, ddi_get_lbolt() + hz);
84 85 tq->tq_maxalloc_wait--;
85 86 if (rv > 0)
86 87 goto again; /* signaled */
87 88 }
88 89 mutex_exit(&tq->tq_lock);
89 90
90 91 t = kmem_alloc(sizeof (taskq_ent_t), tqflags);
91 92
92 93 mutex_enter(&tq->tq_lock);
93 94 if (t != NULL)
94 95 tq->tq_nalloc++;
95 96 }
96 97 return (t);
97 98 }
98 99
99 100 static void
100 101 task_free(taskq_t *tq, taskq_ent_t *t)
101 102 {
102 103 if (tq->tq_nalloc <= tq->tq_minalloc) {
103 104 t->tqent_next = tq->tq_freelist;
104 105 tq->tq_freelist = t;
105 106 } else {
106 107 tq->tq_nalloc--;
107 108 mutex_exit(&tq->tq_lock);
108 109 kmem_free(t, sizeof (taskq_ent_t));
109 110 mutex_enter(&tq->tq_lock);
110 111 }
111 112
112 113 if (tq->tq_maxalloc_wait)
113 114 cv_signal(&tq->tq_maxalloc_cv);
114 115 }
115 116
116 117 taskqid_t
117 118 taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
118 119 {
119 120 taskq_ent_t *t;
120 121
121 122 if (taskq_now) {
122 123 func(arg);
123 124 return (1);
124 125 }
125 126
126 127 mutex_enter(&tq->tq_lock);
127 128 ASSERT(tq->tq_flags & TASKQ_ACTIVE);
128 129 if ((t = task_alloc(tq, tqflags)) == NULL) {
129 130 mutex_exit(&tq->tq_lock);
130 131 return (0);
131 132 }
132 133 if (tqflags & TQ_FRONT) {
133 134 t->tqent_next = tq->tq_task.tqent_next;
134 135 t->tqent_prev = &tq->tq_task;
135 136 } else {
136 137 t->tqent_next = &tq->tq_task;
137 138 t->tqent_prev = tq->tq_task.tqent_prev;
138 139 }
139 140 t->tqent_next->tqent_prev = t;
140 141 t->tqent_prev->tqent_next = t;
141 142 t->tqent_func = func;
142 143 t->tqent_arg = arg;
143 144 t->tqent_flags = 0;
144 145 cv_signal(&tq->tq_dispatch_cv);
145 146 mutex_exit(&tq->tq_lock);
146 147 return (1);
147 148 }
148 149
149 150 void
150 151 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
151 152 taskq_ent_t *t)
152 153 {
153 154 ASSERT(func != NULL);
154 155 ASSERT(!(tq->tq_flags & TASKQ_DYNAMIC));
155 156
156 157 /*
157 158 * Mark it as a prealloc'd task. This is important
158 159 * to ensure that we don't free it later.
159 160 */
160 161 t->tqent_flags |= TQENT_FLAG_PREALLOC;
161 162 /*
162 163 * Enqueue the task to the underlying queue.
163 164 */
164 165 mutex_enter(&tq->tq_lock);
165 166
166 167 if (flags & TQ_FRONT) {
167 168 t->tqent_next = tq->tq_task.tqent_next;
168 169 t->tqent_prev = &tq->tq_task;
169 170 } else {
170 171 t->tqent_next = &tq->tq_task;
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171 172 t->tqent_prev = tq->tq_task.tqent_prev;
172 173 }
173 174 t->tqent_next->tqent_prev = t;
174 175 t->tqent_prev->tqent_next = t;
175 176 t->tqent_func = func;
176 177 t->tqent_arg = arg;
177 178 cv_signal(&tq->tq_dispatch_cv);
178 179 mutex_exit(&tq->tq_lock);
179 180 }
180 181
182 +boolean_t
183 +taskq_empty(taskq_t *tq)
184 +{
185 + boolean_t rv;
186 +
187 + mutex_enter(&tq->tq_lock);
188 + rv = (tq->tq_task.tqent_next == &tq->tq_task) && (tq->tq_active == 0);
189 + mutex_exit(&tq->tq_lock);
190 +
191 + return (rv);
192 +}
193 +
181 194 void
182 195 taskq_wait(taskq_t *tq)
183 196 {
184 197 mutex_enter(&tq->tq_lock);
185 198 while (tq->tq_task.tqent_next != &tq->tq_task || tq->tq_active != 0)
186 199 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
187 200 mutex_exit(&tq->tq_lock);
188 201 }
189 202
190 203 static void *
191 204 taskq_thread(void *arg)
192 205 {
193 206 taskq_t *tq = arg;
194 207 taskq_ent_t *t;
195 208 boolean_t prealloc;
196 209
197 210 mutex_enter(&tq->tq_lock);
198 211 while (tq->tq_flags & TASKQ_ACTIVE) {
199 212 if ((t = tq->tq_task.tqent_next) == &tq->tq_task) {
200 213 if (--tq->tq_active == 0)
201 214 cv_broadcast(&tq->tq_wait_cv);
202 215 cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
203 216 tq->tq_active++;
204 217 continue;
205 218 }
206 219 t->tqent_prev->tqent_next = t->tqent_next;
207 220 t->tqent_next->tqent_prev = t->tqent_prev;
208 221 t->tqent_next = NULL;
209 222 t->tqent_prev = NULL;
210 223 prealloc = t->tqent_flags & TQENT_FLAG_PREALLOC;
211 224 mutex_exit(&tq->tq_lock);
212 225
213 226 rw_enter(&tq->tq_threadlock, RW_READER);
214 227 t->tqent_func(t->tqent_arg);
215 228 rw_exit(&tq->tq_threadlock);
216 229
217 230 mutex_enter(&tq->tq_lock);
218 231 if (!prealloc)
219 232 task_free(tq, t);
220 233 }
221 234 tq->tq_nthreads--;
222 235 cv_broadcast(&tq->tq_wait_cv);
223 236 mutex_exit(&tq->tq_lock);
224 237 return (NULL);
225 238 }
226 239
227 240 /*ARGSUSED*/
228 241 taskq_t *
229 242 taskq_create(const char *name, int nthreads, pri_t pri,
230 243 int minalloc, int maxalloc, uint_t flags)
231 244 {
232 245 taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
233 246 int t;
234 247
235 248 if (flags & TASKQ_THREADS_CPU_PCT) {
236 249 int pct;
237 250 ASSERT3S(nthreads, >=, 0);
238 251 ASSERT3S(nthreads, <=, 100);
239 252 pct = MIN(nthreads, 100);
240 253 pct = MAX(pct, 0);
241 254
242 255 nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
243 256 nthreads = MAX(nthreads, 1); /* need at least 1 thread */
244 257 } else {
245 258 ASSERT3S(nthreads, >=, 1);
246 259 }
247 260
248 261 rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
249 262 mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
250 263 cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
251 264 cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
252 265 cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
253 266 (void) strncpy(tq->tq_name, name, TASKQ_NAMELEN + 1);
254 267 tq->tq_flags = flags | TASKQ_ACTIVE;
255 268 tq->tq_active = nthreads;
256 269 tq->tq_nthreads = nthreads;
257 270 tq->tq_minalloc = minalloc;
258 271 tq->tq_maxalloc = maxalloc;
259 272 tq->tq_task.tqent_next = &tq->tq_task;
260 273 tq->tq_task.tqent_prev = &tq->tq_task;
261 274 tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP);
262 275
263 276 if (flags & TASKQ_PREPOPULATE) {
264 277 mutex_enter(&tq->tq_lock);
265 278 while (minalloc-- > 0)
266 279 task_free(tq, task_alloc(tq, KM_SLEEP));
267 280 mutex_exit(&tq->tq_lock);
268 281 }
269 282
270 283 for (t = 0; t < nthreads; t++)
271 284 (void) thr_create(0, 0, taskq_thread,
272 285 tq, THR_BOUND, &tq->tq_threadlist[t]);
273 286
274 287 return (tq);
275 288 }
276 289
277 290 void
278 291 taskq_destroy(taskq_t *tq)
279 292 {
280 293 int t;
281 294 int nthreads = tq->tq_nthreads;
282 295
283 296 taskq_wait(tq);
284 297
285 298 mutex_enter(&tq->tq_lock);
286 299
287 300 tq->tq_flags &= ~TASKQ_ACTIVE;
288 301 cv_broadcast(&tq->tq_dispatch_cv);
289 302
290 303 while (tq->tq_nthreads != 0)
291 304 cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
292 305
293 306 tq->tq_minalloc = 0;
294 307 while (tq->tq_nalloc != 0) {
295 308 ASSERT(tq->tq_freelist != NULL);
296 309 task_free(tq, task_alloc(tq, KM_SLEEP));
297 310 }
298 311
299 312 mutex_exit(&tq->tq_lock);
300 313
301 314 for (t = 0; t < nthreads; t++)
302 315 (void) thr_join(tq->tq_threadlist[t], NULL, NULL);
303 316
304 317 kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t));
305 318
306 319 rw_destroy(&tq->tq_threadlock);
307 320 mutex_destroy(&tq->tq_lock);
308 321 cv_destroy(&tq->tq_dispatch_cv);
309 322 cv_destroy(&tq->tq_wait_cv);
310 323 cv_destroy(&tq->tq_maxalloc_cv);
311 324
312 325 kmem_free(tq, sizeof (taskq_t));
313 326 }
314 327
315 328 int
316 329 taskq_member(taskq_t *tq, void *t)
317 330 {
318 331 int i;
319 332
320 333 if (taskq_now)
321 334 return (1);
322 335
323 336 for (i = 0; i < tq->tq_nthreads; i++)
324 337 if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t)
325 338 return (1);
326 339
327 340 return (0);
328 341 }
329 342
330 343 void
331 344 system_taskq_init(void)
332 345 {
333 346 system_taskq = taskq_create("system_taskq", 64, minclsyspri, 4, 512,
334 347 TASKQ_DYNAMIC | TASKQ_PREPOPULATE);
335 348 }
336 349
337 350 void
338 351 system_taskq_fini(void)
339 352 {
340 353 taskq_destroy(system_taskq);
341 354 system_taskq = NULL; /* defensive */
342 355 }
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