Commit | Line | Data |
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b57aee66 PM |
1 | /* |
2 | * urcu-call-rcu.c | |
3 | * | |
4 | * Userspace RCU library - batch memory reclamation with kernel API | |
5 | * | |
6 | * Copyright (c) 2010 Paul E. McKenney <paulmck@linux.vnet.ibm.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
c1d2c60b | 23 | #define _GNU_SOURCE |
5161f31e | 24 | #define _LGPL_SOURCE |
b57aee66 PM |
25 | #include <stdio.h> |
26 | #include <pthread.h> | |
27 | #include <signal.h> | |
28 | #include <assert.h> | |
29 | #include <stdlib.h> | |
6d841bc2 | 30 | #include <stdint.h> |
b57aee66 PM |
31 | #include <string.h> |
32 | #include <errno.h> | |
33 | #include <poll.h> | |
34 | #include <sys/time.h> | |
b57aee66 | 35 | #include <unistd.h> |
c1d2c60b | 36 | #include <sched.h> |
b57aee66 PM |
37 | |
38 | #include "config.h" | |
a47dd11c | 39 | #include "compat-getcpu.h" |
5161f31e | 40 | #include "urcu/wfcqueue.h" |
b57aee66 PM |
41 | #include "urcu-call-rcu.h" |
42 | #include "urcu-pointer.h" | |
3c24913f | 43 | #include "urcu/list.h" |
41849996 | 44 | #include "urcu/futex.h" |
bd252a04 | 45 | #include "urcu/tls-compat.h" |
81dd9134 | 46 | #include "urcu/ref.h" |
4a6d7378 | 47 | #include "urcu-die.h" |
b57aee66 | 48 | |
8e3690db MD |
49 | #define SET_AFFINITY_CHECK_PERIOD (1U << 8) /* 256 */ |
50 | #define SET_AFFINITY_CHECK_PERIOD_MASK (SET_AFFINITY_CHECK_PERIOD - 1) | |
51 | ||
b57aee66 PM |
52 | /* Data structure that identifies a call_rcu thread. */ |
53 | ||
54 | struct call_rcu_data { | |
5161f31e | 55 | /* |
0b8ab7df MD |
56 | * We do not align head on a different cache-line than tail |
57 | * mainly because call_rcu callback-invocation threads use | |
58 | * batching ("splice") to get an entire list of callbacks, which | |
59 | * effectively empties the queue, and requires to touch the tail | |
60 | * anyway. | |
5161f31e | 61 | */ |
b9f893b6 | 62 | struct cds_wfcq_tail cbs_tail; |
0b8ab7df | 63 | struct cds_wfcq_head cbs_head; |
b57aee66 | 64 | unsigned long flags; |
6d841bc2 | 65 | int32_t futex; |
73987721 | 66 | unsigned long qlen; /* maintained for debugging. */ |
b57aee66 | 67 | pthread_t tid; |
c1d2c60b | 68 | int cpu_affinity; |
8e3690db | 69 | unsigned long gp_count; |
3c24913f | 70 | struct cds_list_head list; |
b57aee66 PM |
71 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
72 | ||
b7f721d9 MD |
73 | struct call_rcu_completion { |
74 | int barrier_count; | |
75 | int32_t futex; | |
81dd9134 | 76 | struct urcu_ref ref; |
b7f721d9 MD |
77 | }; |
78 | ||
79 | struct call_rcu_completion_work { | |
80 | struct rcu_head head; | |
81 | struct call_rcu_completion *completion; | |
82 | }; | |
83 | ||
3c24913f PM |
84 | /* |
85 | * List of all call_rcu_data structures to keep valgrind happy. | |
86 | * Protected by call_rcu_mutex. | |
87 | */ | |
88 | ||
bab44e28 | 89 | static CDS_LIST_HEAD(call_rcu_data_list); |
3c24913f | 90 | |
b57aee66 PM |
91 | /* Link a thread using call_rcu() to its call_rcu thread. */ |
92 | ||
bd252a04 | 93 | static DEFINE_URCU_TLS(struct call_rcu_data *, thread_call_rcu_data); |
b57aee66 | 94 | |
e85451a1 MD |
95 | /* |
96 | * Guard call_rcu thread creation and atfork handlers. | |
97 | */ | |
b57aee66 PM |
98 | static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER; |
99 | ||
100 | /* If a given thread does not have its own call_rcu thread, this is default. */ | |
101 | ||
102 | static struct call_rcu_data *default_call_rcu_data; | |
103 | ||
4494af1d MD |
104 | static struct urcu_atfork *registered_rculfhash_atfork; |
105 | static unsigned long registered_rculfhash_atfork_refcount; | |
106 | ||
b57aee66 PM |
107 | /* |
108 | * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are | |
109 | * available, then we can have call_rcu threads assigned to individual | |
110 | * CPUs rather than only to specific threads. | |
111 | */ | |
112 | ||
a47dd11c | 113 | #if defined(HAVE_SYSCONF) && (defined(HAVE_SCHED_GETCPU) || defined(HAVE_GETCPUID)) |
b57aee66 PM |
114 | |
115 | /* | |
116 | * Pointer to array of pointers to per-CPU call_rcu_data structures | |
618b2595 MD |
117 | * and # CPUs. per_cpu_call_rcu_data is a RCU-protected pointer to an |
118 | * array of RCU-protected pointers to call_rcu_data. call_rcu acts as a | |
119 | * RCU read-side and reads per_cpu_call_rcu_data and the per-cpu pointer | |
120 | * without mutex. The call_rcu_mutex protects updates. | |
b57aee66 PM |
121 | */ |
122 | ||
123 | static struct call_rcu_data **per_cpu_call_rcu_data; | |
124 | static long maxcpus; | |
125 | ||
60af049d LJ |
126 | static void maxcpus_reset(void) |
127 | { | |
128 | maxcpus = 0; | |
129 | } | |
130 | ||
b57aee66 PM |
131 | /* Allocate the array if it has not already been allocated. */ |
132 | ||
133 | static void alloc_cpu_call_rcu_data(void) | |
134 | { | |
135 | struct call_rcu_data **p; | |
136 | static int warned = 0; | |
137 | ||
138 | if (maxcpus != 0) | |
139 | return; | |
140 | maxcpus = sysconf(_SC_NPROCESSORS_CONF); | |
141 | if (maxcpus <= 0) { | |
142 | return; | |
143 | } | |
144 | p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data)); | |
145 | if (p != NULL) { | |
146 | memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data)); | |
618b2595 | 147 | rcu_set_pointer(&per_cpu_call_rcu_data, p); |
b57aee66 PM |
148 | } else { |
149 | if (!warned) { | |
150 | fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n"); | |
151 | } | |
152 | warned = 1; | |
153 | } | |
154 | } | |
155 | ||
63b495d8 | 156 | #else /* #if defined(HAVE_SYSCONF) && defined(HAVE_SCHED_GETCPU) */ |
b57aee66 | 157 | |
f9437098 MD |
158 | /* |
159 | * per_cpu_call_rcu_data should be constant, but some functions below, used both | |
160 | * for cases where cpu number is available and not available, assume it it not | |
161 | * constant. | |
162 | */ | |
163 | static struct call_rcu_data **per_cpu_call_rcu_data = NULL; | |
b57aee66 PM |
164 | static const long maxcpus = -1; |
165 | ||
60af049d LJ |
166 | static void maxcpus_reset(void) |
167 | { | |
168 | } | |
169 | ||
b57aee66 PM |
170 | static void alloc_cpu_call_rcu_data(void) |
171 | { | |
172 | } | |
173 | ||
63b495d8 | 174 | #endif /* #else #if defined(HAVE_SYSCONF) && defined(HAVE_SCHED_GETCPU) */ |
b57aee66 PM |
175 | |
176 | /* Acquire the specified pthread mutex. */ | |
177 | ||
178 | static void call_rcu_lock(pthread_mutex_t *pmp) | |
179 | { | |
4a6d7378 MD |
180 | int ret; |
181 | ||
182 | ret = pthread_mutex_lock(pmp); | |
183 | if (ret) | |
184 | urcu_die(ret); | |
b57aee66 PM |
185 | } |
186 | ||
187 | /* Release the specified pthread mutex. */ | |
188 | ||
189 | static void call_rcu_unlock(pthread_mutex_t *pmp) | |
190 | { | |
4a6d7378 MD |
191 | int ret; |
192 | ||
193 | ret = pthread_mutex_unlock(pmp); | |
194 | if (ret) | |
195 | urcu_die(ret); | |
b57aee66 PM |
196 | } |
197 | ||
8e3690db MD |
198 | /* |
199 | * Periodically retry setting CPU affinity if we migrate. | |
200 | * Losing affinity can be caused by CPU hotunplug/hotplug, or by | |
201 | * cpuset(7). | |
202 | */ | |
c1d2c60b MD |
203 | #if HAVE_SCHED_SETAFFINITY |
204 | static | |
205 | int set_thread_cpu_affinity(struct call_rcu_data *crdp) | |
206 | { | |
207 | cpu_set_t mask; | |
8e3690db | 208 | int ret; |
c1d2c60b MD |
209 | |
210 | if (crdp->cpu_affinity < 0) | |
211 | return 0; | |
8e3690db MD |
212 | if (++crdp->gp_count & SET_AFFINITY_CHECK_PERIOD_MASK) |
213 | return 0; | |
214 | if (urcu_sched_getcpu() == crdp->cpu_affinity) | |
215 | return 0; | |
c1d2c60b MD |
216 | |
217 | CPU_ZERO(&mask); | |
218 | CPU_SET(crdp->cpu_affinity, &mask); | |
219 | #if SCHED_SETAFFINITY_ARGS == 2 | |
8e3690db | 220 | ret = sched_setaffinity(0, &mask); |
c1d2c60b | 221 | #else |
8e3690db | 222 | ret = sched_setaffinity(0, sizeof(mask), &mask); |
c1d2c60b | 223 | #endif |
8e3690db MD |
224 | /* |
225 | * EINVAL is fine: can be caused by hotunplugged CPUs, or by | |
226 | * cpuset(7). This is why we should always retry if we detect | |
227 | * migration. | |
228 | */ | |
229 | if (ret && errno == EINVAL) { | |
230 | ret = 0; | |
231 | errno = 0; | |
232 | } | |
233 | return ret; | |
c1d2c60b MD |
234 | } |
235 | #else | |
236 | static | |
237 | int set_thread_cpu_affinity(struct call_rcu_data *crdp) | |
238 | { | |
239 | return 0; | |
240 | } | |
241 | #endif | |
242 | ||
03fe58b3 MD |
243 | static void call_rcu_wait(struct call_rcu_data *crdp) |
244 | { | |
245 | /* Read call_rcu list before read futex */ | |
246 | cmm_smp_mb(); | |
b0a841b4 MD |
247 | if (uatomic_read(&crdp->futex) != -1) |
248 | return; | |
249 | while (futex_async(&crdp->futex, FUTEX_WAIT, -1, | |
250 | NULL, NULL, 0)) { | |
251 | switch (errno) { | |
252 | case EWOULDBLOCK: | |
253 | /* Value already changed. */ | |
254 | return; | |
255 | case EINTR: | |
256 | /* Retry if interrupted by signal. */ | |
257 | break; /* Get out of switch. */ | |
258 | default: | |
259 | /* Unexpected error. */ | |
260 | urcu_die(errno); | |
261 | } | |
262 | } | |
03fe58b3 MD |
263 | } |
264 | ||
265 | static void call_rcu_wake_up(struct call_rcu_data *crdp) | |
266 | { | |
267 | /* Write to call_rcu list before reading/writing futex */ | |
268 | cmm_smp_mb(); | |
a0b7f7ea | 269 | if (caa_unlikely(uatomic_read(&crdp->futex) == -1)) { |
03fe58b3 | 270 | uatomic_set(&crdp->futex, 0); |
b0a841b4 MD |
271 | if (futex_async(&crdp->futex, FUTEX_WAKE, 1, |
272 | NULL, NULL, 0) < 0) | |
273 | urcu_die(errno); | |
03fe58b3 MD |
274 | } |
275 | } | |
276 | ||
b7f721d9 MD |
277 | static void call_rcu_completion_wait(struct call_rcu_completion *completion) |
278 | { | |
279 | /* Read completion barrier count before read futex */ | |
280 | cmm_smp_mb(); | |
b0a841b4 MD |
281 | if (uatomic_read(&completion->futex) != -1) |
282 | return; | |
283 | while (futex_async(&completion->futex, FUTEX_WAIT, -1, | |
284 | NULL, NULL, 0)) { | |
285 | switch (errno) { | |
286 | case EWOULDBLOCK: | |
287 | /* Value already changed. */ | |
288 | return; | |
289 | case EINTR: | |
290 | /* Retry if interrupted by signal. */ | |
291 | break; /* Get out of switch. */ | |
292 | default: | |
293 | /* Unexpected error. */ | |
294 | urcu_die(errno); | |
295 | } | |
296 | } | |
b7f721d9 MD |
297 | } |
298 | ||
299 | static void call_rcu_completion_wake_up(struct call_rcu_completion *completion) | |
300 | { | |
301 | /* Write to completion barrier count before reading/writing futex */ | |
302 | cmm_smp_mb(); | |
303 | if (caa_unlikely(uatomic_read(&completion->futex) == -1)) { | |
304 | uatomic_set(&completion->futex, 0); | |
b0a841b4 MD |
305 | if (futex_async(&completion->futex, FUTEX_WAKE, 1, |
306 | NULL, NULL, 0) < 0) | |
307 | urcu_die(errno); | |
b7f721d9 MD |
308 | } |
309 | } | |
310 | ||
b57aee66 PM |
311 | /* This is the code run by each call_rcu thread. */ |
312 | ||
313 | static void *call_rcu_thread(void *arg) | |
314 | { | |
315 | unsigned long cbcount; | |
5161f31e | 316 | struct call_rcu_data *crdp = (struct call_rcu_data *) arg; |
2870aa1e | 317 | int rt = !!(uatomic_read(&crdp->flags) & URCU_CALL_RCU_RT); |
b57aee66 | 318 | |
8e3690db | 319 | if (set_thread_cpu_affinity(crdp)) |
4a6d7378 | 320 | urcu_die(errno); |
c1d2c60b | 321 | |
765f3ead MD |
322 | /* |
323 | * If callbacks take a read-side lock, we need to be registered. | |
324 | */ | |
325 | rcu_register_thread(); | |
326 | ||
bd252a04 | 327 | URCU_TLS(thread_call_rcu_data) = crdp; |
bc94ca9b MD |
328 | if (!rt) { |
329 | uatomic_dec(&crdp->futex); | |
330 | /* Decrement futex before reading call_rcu list */ | |
331 | cmm_smp_mb(); | |
332 | } | |
b57aee66 | 333 | for (;;) { |
5161f31e MD |
334 | struct cds_wfcq_head cbs_tmp_head; |
335 | struct cds_wfcq_tail cbs_tmp_tail; | |
336 | struct cds_wfcq_node *cbs, *cbs_tmp_n; | |
ae25b7e2 | 337 | enum cds_wfcq_ret splice_ret; |
5161f31e | 338 | |
8e3690db MD |
339 | if (set_thread_cpu_affinity(crdp)) |
340 | urcu_die(errno); | |
341 | ||
e85451a1 MD |
342 | if (uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSE) { |
343 | /* | |
344 | * Pause requested. Become quiescent: remove | |
345 | * ourself from all global lists, and don't | |
346 | * process any callback. The callback lists may | |
347 | * still be non-empty though. | |
348 | */ | |
349 | rcu_unregister_thread(); | |
350 | cmm_smp_mb__before_uatomic_or(); | |
351 | uatomic_or(&crdp->flags, URCU_CALL_RCU_PAUSED); | |
352 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSE) != 0) | |
109105b7 | 353 | (void) poll(NULL, 0, 1); |
fc236e5e KF |
354 | uatomic_and(&crdp->flags, ~URCU_CALL_RCU_PAUSED); |
355 | cmm_smp_mb__after_uatomic_and(); | |
e85451a1 MD |
356 | rcu_register_thread(); |
357 | } | |
358 | ||
5161f31e | 359 | cds_wfcq_init(&cbs_tmp_head, &cbs_tmp_tail); |
ae25b7e2 MD |
360 | splice_ret = __cds_wfcq_splice_blocking(&cbs_tmp_head, |
361 | &cbs_tmp_tail, &crdp->cbs_head, &crdp->cbs_tail); | |
362 | assert(splice_ret != CDS_WFCQ_RET_WOULDBLOCK); | |
363 | assert(splice_ret != CDS_WFCQ_RET_DEST_NON_EMPTY); | |
364 | if (splice_ret != CDS_WFCQ_RET_SRC_EMPTY) { | |
b57aee66 PM |
365 | synchronize_rcu(); |
366 | cbcount = 0; | |
5161f31e MD |
367 | __cds_wfcq_for_each_blocking_safe(&cbs_tmp_head, |
368 | &cbs_tmp_tail, cbs, cbs_tmp_n) { | |
369 | struct rcu_head *rhp; | |
370 | ||
371 | rhp = caa_container_of(cbs, | |
372 | struct rcu_head, next); | |
b57aee66 PM |
373 | rhp->func(rhp); |
374 | cbcount++; | |
5161f31e | 375 | } |
b57aee66 PM |
376 | uatomic_sub(&crdp->qlen, cbcount); |
377 | } | |
bc94ca9b MD |
378 | if (uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOP) |
379 | break; | |
765f3ead | 380 | rcu_thread_offline(); |
bc94ca9b | 381 | if (!rt) { |
5161f31e MD |
382 | if (cds_wfcq_empty(&crdp->cbs_head, |
383 | &crdp->cbs_tail)) { | |
bc94ca9b | 384 | call_rcu_wait(crdp); |
109105b7 | 385 | (void) poll(NULL, 0, 10); |
bc94ca9b | 386 | uatomic_dec(&crdp->futex); |
c768e45e | 387 | /* |
bc94ca9b MD |
388 | * Decrement futex before reading |
389 | * call_rcu list. | |
c768e45e MD |
390 | */ |
391 | cmm_smp_mb(); | |
ccbac24d | 392 | } else { |
109105b7 | 393 | (void) poll(NULL, 0, 10); |
c768e45e | 394 | } |
bc94ca9b | 395 | } else { |
109105b7 | 396 | (void) poll(NULL, 0, 10); |
b57aee66 | 397 | } |
765f3ead | 398 | rcu_thread_online(); |
bc94ca9b MD |
399 | } |
400 | if (!rt) { | |
401 | /* | |
402 | * Read call_rcu list before write futex. | |
403 | */ | |
404 | cmm_smp_mb(); | |
405 | uatomic_set(&crdp->futex, 0); | |
b57aee66 | 406 | } |
2870aa1e | 407 | uatomic_or(&crdp->flags, URCU_CALL_RCU_STOPPED); |
765f3ead | 408 | rcu_unregister_thread(); |
7106ddf8 | 409 | return NULL; |
b57aee66 PM |
410 | } |
411 | ||
412 | /* | |
413 | * Create both a call_rcu thread and the corresponding call_rcu_data | |
3c24913f PM |
414 | * structure, linking the structure in as specified. Caller must hold |
415 | * call_rcu_mutex. | |
b57aee66 PM |
416 | */ |
417 | ||
3c24913f | 418 | static void call_rcu_data_init(struct call_rcu_data **crdpp, |
c1d2c60b MD |
419 | unsigned long flags, |
420 | int cpu_affinity) | |
b57aee66 PM |
421 | { |
422 | struct call_rcu_data *crdp; | |
4a6d7378 | 423 | int ret; |
b57aee66 PM |
424 | |
425 | crdp = malloc(sizeof(*crdp)); | |
4a6d7378 MD |
426 | if (crdp == NULL) |
427 | urcu_die(errno); | |
b57aee66 | 428 | memset(crdp, '\0', sizeof(*crdp)); |
5161f31e | 429 | cds_wfcq_init(&crdp->cbs_head, &crdp->cbs_tail); |
b57aee66 | 430 | crdp->qlen = 0; |
263e3cf9 MD |
431 | crdp->futex = 0; |
432 | crdp->flags = flags; | |
3c24913f | 433 | cds_list_add(&crdp->list, &call_rcu_data_list); |
c1d2c60b | 434 | crdp->cpu_affinity = cpu_affinity; |
8e3690db | 435 | crdp->gp_count = 0; |
b57aee66 PM |
436 | cmm_smp_mb(); /* Structure initialized before pointer is planted. */ |
437 | *crdpp = crdp; | |
4a6d7378 MD |
438 | ret = pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp); |
439 | if (ret) | |
440 | urcu_die(ret); | |
b57aee66 PM |
441 | } |
442 | ||
443 | /* | |
444 | * Return a pointer to the call_rcu_data structure for the specified | |
445 | * CPU, returning NULL if there is none. We cannot automatically | |
446 | * created it because the platform we are running on might not define | |
63b495d8 | 447 | * urcu_sched_getcpu(). |
618b2595 MD |
448 | * |
449 | * The call to this function and use of the returned call_rcu_data | |
450 | * should be protected by RCU read-side lock. | |
b57aee66 PM |
451 | */ |
452 | ||
453 | struct call_rcu_data *get_cpu_call_rcu_data(int cpu) | |
454 | { | |
455 | static int warned = 0; | |
618b2595 | 456 | struct call_rcu_data **pcpu_crdp; |
b57aee66 | 457 | |
618b2595 MD |
458 | pcpu_crdp = rcu_dereference(per_cpu_call_rcu_data); |
459 | if (pcpu_crdp == NULL) | |
b57aee66 PM |
460 | return NULL; |
461 | if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) { | |
462 | fprintf(stderr, "[error] liburcu: get CPU # out of range\n"); | |
463 | warned = 1; | |
464 | } | |
465 | if (cpu < 0 || maxcpus <= cpu) | |
466 | return NULL; | |
618b2595 | 467 | return rcu_dereference(pcpu_crdp[cpu]); |
b57aee66 PM |
468 | } |
469 | ||
470 | /* | |
471 | * Return the tid corresponding to the call_rcu thread whose | |
472 | * call_rcu_data structure is specified. | |
473 | */ | |
474 | ||
475 | pthread_t get_call_rcu_thread(struct call_rcu_data *crdp) | |
476 | { | |
477 | return crdp->tid; | |
478 | } | |
479 | ||
480 | /* | |
481 | * Create a call_rcu_data structure (with thread) and return a pointer. | |
482 | */ | |
483 | ||
c1d2c60b MD |
484 | static struct call_rcu_data *__create_call_rcu_data(unsigned long flags, |
485 | int cpu_affinity) | |
b57aee66 PM |
486 | { |
487 | struct call_rcu_data *crdp; | |
488 | ||
c1d2c60b | 489 | call_rcu_data_init(&crdp, flags, cpu_affinity); |
b57aee66 PM |
490 | return crdp; |
491 | } | |
492 | ||
c1d2c60b MD |
493 | struct call_rcu_data *create_call_rcu_data(unsigned long flags, |
494 | int cpu_affinity) | |
3c24913f PM |
495 | { |
496 | struct call_rcu_data *crdp; | |
497 | ||
498 | call_rcu_lock(&call_rcu_mutex); | |
c1d2c60b | 499 | crdp = __create_call_rcu_data(flags, cpu_affinity); |
3c24913f PM |
500 | call_rcu_unlock(&call_rcu_mutex); |
501 | return crdp; | |
502 | } | |
503 | ||
b57aee66 PM |
504 | /* |
505 | * Set the specified CPU to use the specified call_rcu_data structure. | |
7106ddf8 PM |
506 | * |
507 | * Use NULL to remove a CPU's call_rcu_data structure, but it is | |
508 | * the caller's responsibility to dispose of the removed structure. | |
509 | * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure | |
510 | * (prior to NULLing it out, of course). | |
f9da0936 MD |
511 | * |
512 | * The caller must wait for a grace-period to pass between return from | |
513 | * set_cpu_call_rcu_data() and call to call_rcu_data_free() passing the | |
514 | * previous call rcu data as argument. | |
b57aee66 PM |
515 | */ |
516 | ||
517 | int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp) | |
518 | { | |
dcfc8165 | 519 | static int warned = 0; |
b57aee66 PM |
520 | |
521 | call_rcu_lock(&call_rcu_mutex); | |
f3776786 | 522 | alloc_cpu_call_rcu_data(); |
b57aee66 PM |
523 | if (cpu < 0 || maxcpus <= cpu) { |
524 | if (!warned) { | |
525 | fprintf(stderr, "[error] liburcu: set CPU # out of range\n"); | |
526 | warned = 1; | |
527 | } | |
528 | call_rcu_unlock(&call_rcu_mutex); | |
529 | errno = EINVAL; | |
530 | return -EINVAL; | |
531 | } | |
53a55535 | 532 | |
b57aee66 | 533 | if (per_cpu_call_rcu_data == NULL) { |
3670fef2 | 534 | call_rcu_unlock(&call_rcu_mutex); |
b57aee66 PM |
535 | errno = ENOMEM; |
536 | return -ENOMEM; | |
537 | } | |
53a55535 LJ |
538 | |
539 | if (per_cpu_call_rcu_data[cpu] != NULL && crdp != NULL) { | |
540 | call_rcu_unlock(&call_rcu_mutex); | |
541 | errno = EEXIST; | |
542 | return -EEXIST; | |
543 | } | |
544 | ||
618b2595 | 545 | rcu_set_pointer(&per_cpu_call_rcu_data[cpu], crdp); |
3670fef2 | 546 | call_rcu_unlock(&call_rcu_mutex); |
b57aee66 PM |
547 | return 0; |
548 | } | |
549 | ||
550 | /* | |
551 | * Return a pointer to the default call_rcu_data structure, creating | |
552 | * one if need be. Because we never free call_rcu_data structures, | |
553 | * we don't need to be in an RCU read-side critical section. | |
554 | */ | |
555 | ||
556 | struct call_rcu_data *get_default_call_rcu_data(void) | |
557 | { | |
558 | if (default_call_rcu_data != NULL) | |
559 | return rcu_dereference(default_call_rcu_data); | |
560 | call_rcu_lock(&call_rcu_mutex); | |
561 | if (default_call_rcu_data != NULL) { | |
562 | call_rcu_unlock(&call_rcu_mutex); | |
563 | return default_call_rcu_data; | |
564 | } | |
c1d2c60b | 565 | call_rcu_data_init(&default_call_rcu_data, 0, -1); |
b57aee66 PM |
566 | call_rcu_unlock(&call_rcu_mutex); |
567 | return default_call_rcu_data; | |
568 | } | |
569 | ||
570 | /* | |
571 | * Return the call_rcu_data structure that applies to the currently | |
572 | * running thread. Any call_rcu_data structure assigned specifically | |
573 | * to this thread has first priority, followed by any call_rcu_data | |
574 | * structure assigned to the CPU on which the thread is running, | |
575 | * followed by the default call_rcu_data structure. If there is not | |
576 | * yet a default call_rcu_data structure, one will be created. | |
618b2595 MD |
577 | * |
578 | * Calls to this function and use of the returned call_rcu_data should | |
579 | * be protected by RCU read-side lock. | |
b57aee66 PM |
580 | */ |
581 | struct call_rcu_data *get_call_rcu_data(void) | |
582 | { | |
9744f3bb | 583 | struct call_rcu_data *crd; |
b57aee66 | 584 | |
bd252a04 MD |
585 | if (URCU_TLS(thread_call_rcu_data) != NULL) |
586 | return URCU_TLS(thread_call_rcu_data); | |
9744f3bb LJ |
587 | |
588 | if (maxcpus > 0) { | |
63b495d8 | 589 | crd = get_cpu_call_rcu_data(urcu_sched_getcpu()); |
9744f3bb LJ |
590 | if (crd) |
591 | return crd; | |
b57aee66 | 592 | } |
9744f3bb | 593 | |
b57aee66 PM |
594 | return get_default_call_rcu_data(); |
595 | } | |
596 | ||
597 | /* | |
598 | * Return a pointer to this task's call_rcu_data if there is one. | |
599 | */ | |
600 | ||
601 | struct call_rcu_data *get_thread_call_rcu_data(void) | |
602 | { | |
bd252a04 | 603 | return URCU_TLS(thread_call_rcu_data); |
b57aee66 PM |
604 | } |
605 | ||
606 | /* | |
607 | * Set this task's call_rcu_data structure as specified, regardless | |
608 | * of whether or not this task already had one. (This allows switching | |
609 | * to and from real-time call_rcu threads, for example.) | |
7106ddf8 PM |
610 | * |
611 | * Use NULL to remove a thread's call_rcu_data structure, but it is | |
612 | * the caller's responsibility to dispose of the removed structure. | |
613 | * Use get_thread_call_rcu_data() to obtain a pointer to the old structure | |
614 | * (prior to NULLing it out, of course). | |
b57aee66 PM |
615 | */ |
616 | ||
617 | void set_thread_call_rcu_data(struct call_rcu_data *crdp) | |
618 | { | |
bd252a04 | 619 | URCU_TLS(thread_call_rcu_data) = crdp; |
b57aee66 PM |
620 | } |
621 | ||
622 | /* | |
623 | * Create a separate call_rcu thread for each CPU. This does not | |
624 | * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data() | |
0938c541 MD |
625 | * function if you want that behavior. Should be paired with |
626 | * free_all_cpu_call_rcu_data() to teardown these call_rcu worker | |
627 | * threads. | |
b57aee66 PM |
628 | */ |
629 | ||
630 | int create_all_cpu_call_rcu_data(unsigned long flags) | |
631 | { | |
632 | int i; | |
633 | struct call_rcu_data *crdp; | |
634 | int ret; | |
635 | ||
636 | call_rcu_lock(&call_rcu_mutex); | |
637 | alloc_cpu_call_rcu_data(); | |
638 | call_rcu_unlock(&call_rcu_mutex); | |
639 | if (maxcpus <= 0) { | |
640 | errno = EINVAL; | |
641 | return -EINVAL; | |
642 | } | |
643 | if (per_cpu_call_rcu_data == NULL) { | |
644 | errno = ENOMEM; | |
645 | return -ENOMEM; | |
646 | } | |
647 | for (i = 0; i < maxcpus; i++) { | |
648 | call_rcu_lock(&call_rcu_mutex); | |
649 | if (get_cpu_call_rcu_data(i)) { | |
650 | call_rcu_unlock(&call_rcu_mutex); | |
651 | continue; | |
652 | } | |
c1d2c60b | 653 | crdp = __create_call_rcu_data(flags, i); |
b57aee66 PM |
654 | if (crdp == NULL) { |
655 | call_rcu_unlock(&call_rcu_mutex); | |
656 | errno = ENOMEM; | |
657 | return -ENOMEM; | |
658 | } | |
659 | call_rcu_unlock(&call_rcu_mutex); | |
660 | if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) { | |
356c8794 LJ |
661 | call_rcu_data_free(crdp); |
662 | ||
663 | /* it has been created by other thread */ | |
664 | if (ret == -EEXIST) | |
665 | continue; | |
666 | ||
667 | return ret; | |
b57aee66 PM |
668 | } |
669 | } | |
670 | return 0; | |
671 | } | |
672 | ||
7106ddf8 PM |
673 | /* |
674 | * Wake up the call_rcu thread corresponding to the specified | |
675 | * call_rcu_data structure. | |
676 | */ | |
677 | static void wake_call_rcu_thread(struct call_rcu_data *crdp) | |
678 | { | |
263e3cf9 MD |
679 | if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) |
680 | call_rcu_wake_up(crdp); | |
7106ddf8 PM |
681 | } |
682 | ||
b7f721d9 MD |
683 | static void _call_rcu(struct rcu_head *head, |
684 | void (*func)(struct rcu_head *head), | |
685 | struct call_rcu_data *crdp) | |
686 | { | |
687 | cds_wfcq_node_init(&head->next); | |
688 | head->func = func; | |
689 | cds_wfcq_enqueue(&crdp->cbs_head, &crdp->cbs_tail, &head->next); | |
690 | uatomic_inc(&crdp->qlen); | |
691 | wake_call_rcu_thread(crdp); | |
692 | } | |
693 | ||
b57aee66 PM |
694 | /* |
695 | * Schedule a function to be invoked after a following grace period. | |
696 | * This is the only function that must be called -- the others are | |
697 | * only present to allow applications to tune their use of RCU for | |
698 | * maximum performance. | |
699 | * | |
700 | * Note that unless a call_rcu thread has not already been created, | |
701 | * the first invocation of call_rcu() will create one. So, if you | |
702 | * need the first invocation of call_rcu() to be fast, make sure | |
703 | * to create a call_rcu thread first. One way to accomplish this is | |
704 | * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data(). | |
618b2595 MD |
705 | * |
706 | * call_rcu must be called by registered RCU read-side threads. | |
b57aee66 | 707 | */ |
b57aee66 PM |
708 | void call_rcu(struct rcu_head *head, |
709 | void (*func)(struct rcu_head *head)) | |
710 | { | |
711 | struct call_rcu_data *crdp; | |
712 | ||
618b2595 | 713 | /* Holding rcu read-side lock across use of per-cpu crdp */ |
ffb4aaa7 | 714 | _rcu_read_lock(); |
b57aee66 | 715 | crdp = get_call_rcu_data(); |
b7f721d9 | 716 | _call_rcu(head, func, crdp); |
ffb4aaa7 | 717 | _rcu_read_unlock(); |
7106ddf8 PM |
718 | } |
719 | ||
720 | /* | |
721 | * Free up the specified call_rcu_data structure, terminating the | |
722 | * associated call_rcu thread. The caller must have previously | |
723 | * removed the call_rcu_data structure from per-thread or per-CPU | |
724 | * usage. For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU | |
725 | * call_rcu_data structures or set_thread_call_rcu_data(NULL) for | |
726 | * per-thread call_rcu_data structures. | |
727 | * | |
728 | * We silently refuse to free up the default call_rcu_data structure | |
729 | * because that is where we put any leftover callbacks. Note that | |
730 | * the possibility of self-spawning callbacks makes it impossible | |
731 | * to execute all the callbacks in finite time without putting any | |
732 | * newly spawned callbacks somewhere else. The "somewhere else" of | |
733 | * last resort is the default call_rcu_data structure. | |
734 | * | |
735 | * We also silently refuse to free NULL pointers. This simplifies | |
736 | * the calling code. | |
f9da0936 MD |
737 | * |
738 | * The caller must wait for a grace-period to pass between return from | |
739 | * set_cpu_call_rcu_data() and call to call_rcu_data_free() passing the | |
740 | * previous call rcu data as argument. | |
03e5118f MD |
741 | * |
742 | * Note: introducing __cds_wfcq_splice_blocking() in this function fixed | |
743 | * a list corruption bug in the 0.7.x series. The equivalent fix | |
744 | * appeared in 0.6.8 for the stable-0.6 branch. | |
7106ddf8 PM |
745 | */ |
746 | void call_rcu_data_free(struct call_rcu_data *crdp) | |
747 | { | |
7106ddf8 PM |
748 | if (crdp == NULL || crdp == default_call_rcu_data) { |
749 | return; | |
750 | } | |
2870aa1e PB |
751 | if ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0) { |
752 | uatomic_or(&crdp->flags, URCU_CALL_RCU_STOP); | |
7106ddf8 | 753 | wake_call_rcu_thread(crdp); |
2870aa1e | 754 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0) |
109105b7 | 755 | (void) poll(NULL, 0, 1); |
7106ddf8 | 756 | } |
5161f31e | 757 | if (!cds_wfcq_empty(&crdp->cbs_head, &crdp->cbs_tail)) { |
698d0778 MD |
758 | /* Create default call rcu data if need be */ |
759 | (void) get_default_call_rcu_data(); | |
5161f31e MD |
760 | __cds_wfcq_splice_blocking(&default_call_rcu_data->cbs_head, |
761 | &default_call_rcu_data->cbs_tail, | |
762 | &crdp->cbs_head, &crdp->cbs_tail); | |
7106ddf8 PM |
763 | uatomic_add(&default_call_rcu_data->qlen, |
764 | uatomic_read(&crdp->qlen)); | |
1e92aa15 | 765 | wake_call_rcu_thread(default_call_rcu_data); |
7106ddf8 | 766 | } |
59dc9e9d | 767 | |
b75dffe6 | 768 | call_rcu_lock(&call_rcu_mutex); |
59dc9e9d | 769 | cds_list_del(&crdp->list); |
b75dffe6 LJ |
770 | call_rcu_unlock(&call_rcu_mutex); |
771 | ||
59dc9e9d | 772 | free(crdp); |
7106ddf8 PM |
773 | } |
774 | ||
775 | /* | |
776 | * Clean up all the per-CPU call_rcu threads. | |
777 | */ | |
778 | void free_all_cpu_call_rcu_data(void) | |
779 | { | |
780 | int cpu; | |
618b2595 MD |
781 | struct call_rcu_data **crdp; |
782 | static int warned = 0; | |
7106ddf8 PM |
783 | |
784 | if (maxcpus <= 0) | |
785 | return; | |
618b2595 MD |
786 | |
787 | crdp = malloc(sizeof(*crdp) * maxcpus); | |
788 | if (!crdp) { | |
789 | if (!warned) { | |
790 | fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n"); | |
791 | } | |
792 | warned = 1; | |
d31150b4 | 793 | return; |
618b2595 MD |
794 | } |
795 | ||
7106ddf8 | 796 | for (cpu = 0; cpu < maxcpus; cpu++) { |
618b2595 MD |
797 | crdp[cpu] = get_cpu_call_rcu_data(cpu); |
798 | if (crdp[cpu] == NULL) | |
7106ddf8 PM |
799 | continue; |
800 | set_cpu_call_rcu_data(cpu, NULL); | |
7106ddf8 | 801 | } |
618b2595 MD |
802 | /* |
803 | * Wait for call_rcu sites acting as RCU readers of the | |
804 | * call_rcu_data to become quiescent. | |
805 | */ | |
806 | synchronize_rcu(); | |
807 | for (cpu = 0; cpu < maxcpus; cpu++) { | |
808 | if (crdp[cpu] == NULL) | |
809 | continue; | |
810 | call_rcu_data_free(crdp[cpu]); | |
811 | } | |
812 | free(crdp); | |
7106ddf8 PM |
813 | } |
814 | ||
81dd9134 KF |
815 | static |
816 | void free_completion(struct urcu_ref *ref) | |
817 | { | |
818 | struct call_rcu_completion *completion; | |
819 | ||
820 | completion = caa_container_of(ref, struct call_rcu_completion, ref); | |
821 | free(completion); | |
822 | } | |
823 | ||
b7f721d9 MD |
824 | static |
825 | void _rcu_barrier_complete(struct rcu_head *head) | |
826 | { | |
827 | struct call_rcu_completion_work *work; | |
828 | struct call_rcu_completion *completion; | |
829 | ||
830 | work = caa_container_of(head, struct call_rcu_completion_work, head); | |
831 | completion = work->completion; | |
81dd9134 KF |
832 | if (!uatomic_sub_return(&completion->barrier_count, 1)) |
833 | call_rcu_completion_wake_up(completion); | |
834 | urcu_ref_put(&completion->ref, free_completion); | |
b7f721d9 MD |
835 | free(work); |
836 | } | |
837 | ||
838 | /* | |
839 | * Wait for all in-flight call_rcu callbacks to complete execution. | |
840 | */ | |
841 | void rcu_barrier(void) | |
842 | { | |
843 | struct call_rcu_data *crdp; | |
81dd9134 | 844 | struct call_rcu_completion *completion; |
63f0fc6d | 845 | int count = 0; |
b7f721d9 MD |
846 | int was_online; |
847 | ||
848 | /* Put in offline state in QSBR. */ | |
ffb4aaa7 | 849 | was_online = _rcu_read_ongoing(); |
b7f721d9 MD |
850 | if (was_online) |
851 | rcu_thread_offline(); | |
852 | /* | |
853 | * Calling a rcu_barrier() within a RCU read-side critical | |
854 | * section is an error. | |
855 | */ | |
ffb4aaa7 | 856 | if (_rcu_read_ongoing()) { |
b7f721d9 MD |
857 | static int warned = 0; |
858 | ||
859 | if (!warned) { | |
860 | fprintf(stderr, "[error] liburcu: rcu_barrier() called from within RCU read-side critical section.\n"); | |
861 | } | |
862 | warned = 1; | |
863 | goto online; | |
864 | } | |
865 | ||
81dd9134 KF |
866 | completion = calloc(sizeof(*completion), 1); |
867 | if (!completion) | |
868 | urcu_die(errno); | |
869 | ||
b7f721d9 MD |
870 | call_rcu_lock(&call_rcu_mutex); |
871 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) | |
872 | count++; | |
873 | ||
81dd9134 KF |
874 | /* Referenced by rcu_barrier() and each call_rcu thread. */ |
875 | urcu_ref_set(&completion->ref, count + 1); | |
876 | completion->barrier_count = count; | |
b7f721d9 MD |
877 | |
878 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { | |
879 | struct call_rcu_completion_work *work; | |
880 | ||
881 | work = calloc(sizeof(*work), 1); | |
63f0fc6d MD |
882 | if (!work) |
883 | urcu_die(errno); | |
81dd9134 | 884 | work->completion = completion; |
b7f721d9 | 885 | _call_rcu(&work->head, _rcu_barrier_complete, crdp); |
b7f721d9 MD |
886 | } |
887 | call_rcu_unlock(&call_rcu_mutex); | |
888 | ||
b7f721d9 MD |
889 | /* Wait for them */ |
890 | for (;;) { | |
81dd9134 | 891 | uatomic_dec(&completion->futex); |
b7f721d9 MD |
892 | /* Decrement futex before reading barrier_count */ |
893 | cmm_smp_mb(); | |
81dd9134 | 894 | if (!uatomic_read(&completion->barrier_count)) |
b7f721d9 | 895 | break; |
81dd9134 | 896 | call_rcu_completion_wait(completion); |
b7f721d9 | 897 | } |
81dd9134 KF |
898 | |
899 | urcu_ref_put(&completion->ref, free_completion); | |
900 | ||
b7f721d9 MD |
901 | online: |
902 | if (was_online) | |
903 | rcu_thread_online(); | |
904 | } | |
905 | ||
81ad2e19 PM |
906 | /* |
907 | * Acquire the call_rcu_mutex in order to ensure that the child sees | |
e85451a1 MD |
908 | * all of the call_rcu() data structures in a consistent state. Ensure |
909 | * that all call_rcu threads are in a quiescent state across fork. | |
81ad2e19 PM |
910 | * Suitable for pthread_atfork() and friends. |
911 | */ | |
912 | void call_rcu_before_fork(void) | |
913 | { | |
e85451a1 | 914 | struct call_rcu_data *crdp; |
4494af1d | 915 | struct urcu_atfork *atfork; |
e85451a1 | 916 | |
81ad2e19 | 917 | call_rcu_lock(&call_rcu_mutex); |
e85451a1 | 918 | |
4494af1d MD |
919 | atfork = registered_rculfhash_atfork; |
920 | if (atfork) | |
921 | atfork->before_fork(atfork->priv); | |
922 | ||
e85451a1 MD |
923 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { |
924 | uatomic_or(&crdp->flags, URCU_CALL_RCU_PAUSE); | |
925 | cmm_smp_mb__after_uatomic_or(); | |
926 | wake_call_rcu_thread(crdp); | |
927 | } | |
928 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { | |
929 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSED) == 0) | |
109105b7 | 930 | (void) poll(NULL, 0, 1); |
e85451a1 | 931 | } |
81ad2e19 PM |
932 | } |
933 | ||
934 | /* | |
935 | * Clean up call_rcu data structures in the parent of a successful fork() | |
936 | * that is not followed by exec() in the child. Suitable for | |
937 | * pthread_atfork() and friends. | |
938 | */ | |
939 | void call_rcu_after_fork_parent(void) | |
940 | { | |
e85451a1 | 941 | struct call_rcu_data *crdp; |
4494af1d | 942 | struct urcu_atfork *atfork; |
e85451a1 MD |
943 | |
944 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) | |
945 | uatomic_and(&crdp->flags, ~URCU_CALL_RCU_PAUSE); | |
fc236e5e KF |
946 | cds_list_for_each_entry(crdp, &call_rcu_data_list, list) { |
947 | while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_PAUSED) != 0) | |
109105b7 | 948 | (void) poll(NULL, 0, 1); |
fc236e5e | 949 | } |
4494af1d MD |
950 | atfork = registered_rculfhash_atfork; |
951 | if (atfork) | |
952 | atfork->after_fork_parent(atfork->priv); | |
81ad2e19 PM |
953 | call_rcu_unlock(&call_rcu_mutex); |
954 | } | |
955 | ||
7106ddf8 PM |
956 | /* |
957 | * Clean up call_rcu data structures in the child of a successful fork() | |
81ad2e19 PM |
958 | * that is not followed by exec(). Suitable for pthread_atfork() and |
959 | * friends. | |
7106ddf8 PM |
960 | */ |
961 | void call_rcu_after_fork_child(void) | |
962 | { | |
077ff173 | 963 | struct call_rcu_data *crdp, *next; |
4494af1d | 964 | struct urcu_atfork *atfork; |
7106ddf8 | 965 | |
81ad2e19 PM |
966 | /* Release the mutex. */ |
967 | call_rcu_unlock(&call_rcu_mutex); | |
968 | ||
4494af1d MD |
969 | atfork = registered_rculfhash_atfork; |
970 | if (atfork) | |
971 | atfork->after_fork_child(atfork->priv); | |
972 | ||
ad1b9909 LJ |
973 | /* Do nothing when call_rcu() has not been used */ |
974 | if (cds_list_empty(&call_rcu_data_list)) | |
975 | return; | |
976 | ||
7106ddf8 PM |
977 | /* |
978 | * Allocate a new default call_rcu_data structure in order | |
979 | * to get a working call_rcu thread to go with it. | |
980 | */ | |
981 | default_call_rcu_data = NULL; | |
982 | (void)get_default_call_rcu_data(); | |
983 | ||
60af049d LJ |
984 | /* Cleanup call_rcu_data pointers before use */ |
985 | maxcpus_reset(); | |
986 | free(per_cpu_call_rcu_data); | |
618b2595 | 987 | rcu_set_pointer(&per_cpu_call_rcu_data, NULL); |
bd252a04 | 988 | URCU_TLS(thread_call_rcu_data) = NULL; |
60af049d | 989 | |
e85451a1 MD |
990 | /* |
991 | * Dispose of all of the rest of the call_rcu_data structures. | |
992 | * Leftover call_rcu callbacks will be merged into the new | |
993 | * default call_rcu thread queue. | |
994 | */ | |
077ff173 | 995 | cds_list_for_each_entry_safe(crdp, next, &call_rcu_data_list, list) { |
7106ddf8 | 996 | if (crdp == default_call_rcu_data) |
077ff173 | 997 | continue; |
2870aa1e | 998 | uatomic_set(&crdp->flags, URCU_CALL_RCU_STOPPED); |
7106ddf8 | 999 | call_rcu_data_free(crdp); |
b57aee66 PM |
1000 | } |
1001 | } | |
4494af1d MD |
1002 | |
1003 | void urcu_register_rculfhash_atfork(struct urcu_atfork *atfork) | |
1004 | { | |
1005 | call_rcu_lock(&call_rcu_mutex); | |
1006 | if (registered_rculfhash_atfork_refcount++) | |
1007 | goto end; | |
1008 | registered_rculfhash_atfork = atfork; | |
1009 | end: | |
1010 | call_rcu_unlock(&call_rcu_mutex); | |
1011 | } | |
1012 | ||
1013 | void urcu_unregister_rculfhash_atfork(struct urcu_atfork *atfork) | |
1014 | { | |
1015 | call_rcu_lock(&call_rcu_mutex); | |
1016 | if (--registered_rculfhash_atfork_refcount) | |
1017 | goto end; | |
1018 | registered_rculfhash_atfork = NULL; | |
1019 | end: | |
1020 | call_rcu_unlock(&call_rcu_mutex); | |
1021 | } |