Commit | Line | Data |
---|---|---|
9f1621ca | 1 | /* |
7ac06cef | 2 | * urcu-qsbr.c |
9f1621ca | 3 | * |
7ac06cef | 4 | * Userspace RCU QSBR library |
9f1621ca | 5 | * |
6982d6d7 | 6 | * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
9f1621ca MD |
7 | * Copyright (c) 2009 Paul E. McKenney, IBM Corporation. |
8 | * | |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | * | |
23 | * IBM's contributions to this file may be relicensed under LGPLv2 or later. | |
24 | */ | |
25 | ||
e37faee1 | 26 | #define URCU_NO_COMPAT_IDENTIFIERS |
71c811bf | 27 | #define _LGPL_SOURCE |
9f1621ca MD |
28 | #include <stdio.h> |
29 | #include <pthread.h> | |
30 | #include <signal.h> | |
9f1621ca | 31 | #include <stdlib.h> |
6d841bc2 | 32 | #include <stdint.h> |
9f1621ca MD |
33 | #include <string.h> |
34 | #include <errno.h> | |
35 | #include <poll.h> | |
36 | ||
01477510 | 37 | #include <urcu/assert.h> |
4477a870 MD |
38 | #include <urcu/wfcqueue.h> |
39 | #include <urcu/map/urcu-qsbr.h> | |
727f819d | 40 | #define BUILD_QSBR_LIB |
4477a870 MD |
41 | #include <urcu/static/urcu-qsbr.h> |
42 | #include <urcu/pointer.h> | |
43 | #include <urcu/tls-compat.h> | |
71c811bf | 44 | |
4a6d7378 | 45 | #include "urcu-die.h" |
cba82d7b | 46 | #include "urcu-wait.h" |
ce28e67a | 47 | #include "urcu-utils.h" |
4a6d7378 | 48 | |
4477a870 | 49 | #define URCU_API_MAP |
9f1621ca | 50 | /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ |
71c811bf | 51 | #undef _LGPL_SOURCE |
4477a870 | 52 | #include <urcu/urcu-qsbr.h> |
71c811bf | 53 | #define _LGPL_SOURCE |
9f1621ca | 54 | |
4477a870 | 55 | void __attribute__((destructor)) urcu_qsbr_exit(void); |
f6d18c64 | 56 | |
731ccb96 MD |
57 | /* |
58 | * rcu_gp_lock ensures mutual exclusion between threads calling | |
59 | * synchronize_rcu(). | |
60 | */ | |
6abb4bd5 | 61 | static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER; |
731ccb96 MD |
62 | /* |
63 | * rcu_registry_lock ensures mutual exclusion between threads | |
64 | * registering and unregistering themselves to/from the registry, and | |
65 | * with threads reading that registry from synchronize_rcu(). However, | |
66 | * this lock is not held all the way through the completion of awaiting | |
67 | * for the grace period. It is sporadically released between iterations | |
68 | * on the registry. | |
69 | * rcu_registry_lock may nest inside rcu_gp_lock. | |
70 | */ | |
71 | static pthread_mutex_t rcu_registry_lock = PTHREAD_MUTEX_INITIALIZER; | |
4477a870 | 72 | struct urcu_gp urcu_qsbr_gp = { .ctr = URCU_QSBR_GP_ONLINE }; |
9f1621ca | 73 | |
408f6d92 PB |
74 | /* |
75 | * Active attempts to check for reader Q.S. before calling futex(). | |
76 | */ | |
77 | #define RCU_QS_ACTIVE_ATTEMPTS 100 | |
78 | ||
9f1621ca MD |
79 | /* |
80 | * Written to only by each individual reader. Read by both the reader and the | |
81 | * writers. | |
82 | */ | |
4477a870 | 83 | DEFINE_URCU_TLS(struct urcu_qsbr_reader, urcu_qsbr_reader); |
9f1621ca | 84 | |
16aa9ee8 | 85 | static CDS_LIST_HEAD(registry); |
9f1621ca | 86 | |
6362f68f | 87 | /* |
bf6822a6 | 88 | * Queue keeping threads awaiting to wait for a grace period. Contains |
6362f68f MD |
89 | * struct gp_waiters_thread objects. |
90 | */ | |
bf6822a6 | 91 | static DEFINE_URCU_WAIT_QUEUE(gp_waiters); |
6362f68f | 92 | |
6abb4bd5 | 93 | static void mutex_lock(pthread_mutex_t *mutex) |
9f1621ca MD |
94 | { |
95 | int ret; | |
96 | ||
97 | #ifndef DISTRUST_SIGNALS_EXTREME | |
6abb4bd5 | 98 | ret = pthread_mutex_lock(mutex); |
4a6d7378 MD |
99 | if (ret) |
100 | urcu_die(ret); | |
9f1621ca | 101 | #else /* #ifndef DISTRUST_SIGNALS_EXTREME */ |
6abb4bd5 | 102 | while ((ret = pthread_mutex_trylock(mutex)) != 0) { |
4a6d7378 MD |
103 | if (ret != EBUSY && ret != EINTR) |
104 | urcu_die(ret); | |
9f1621ca MD |
105 | poll(NULL,0,10); |
106 | } | |
107 | #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ | |
108 | } | |
109 | ||
6abb4bd5 | 110 | static void mutex_unlock(pthread_mutex_t *mutex) |
9f1621ca MD |
111 | { |
112 | int ret; | |
113 | ||
6abb4bd5 | 114 | ret = pthread_mutex_unlock(mutex); |
4a6d7378 MD |
115 | if (ret) |
116 | urcu_die(ret); | |
9f1621ca MD |
117 | } |
118 | ||
bc6c15bb MD |
119 | /* |
120 | * synchronize_rcu() waiting. Single thread. | |
121 | */ | |
4d703340 | 122 | static void wait_gp(void) |
bc6c15bb | 123 | { |
4d703340 | 124 | /* Read reader_gp before read futex */ |
5481ddb3 | 125 | cmm_smp_rmb(); |
4974ad5f MD |
126 | while (uatomic_read(&urcu_qsbr_gp.futex) == -1) { |
127 | if (!futex_noasync(&urcu_qsbr_gp.futex, FUTEX_WAIT, -1, NULL, NULL, 0)) { | |
128 | /* | |
129 | * Prior queued wakeups queued by unrelated code | |
130 | * using the same address can cause futex wait to | |
131 | * return 0 even through the futex value is still | |
132 | * -1 (spurious wakeups). Check the value again | |
133 | * in user-space to validate whether it really | |
134 | * differs from -1. | |
135 | */ | |
136 | continue; | |
137 | } | |
b0a841b4 | 138 | switch (errno) { |
4974ad5f | 139 | case EAGAIN: |
b0a841b4 MD |
140 | /* Value already changed. */ |
141 | return; | |
142 | case EINTR: | |
143 | /* Retry if interrupted by signal. */ | |
4974ad5f | 144 | break; /* Get out of switch. Check again. */ |
b0a841b4 MD |
145 | default: |
146 | /* Unexpected error. */ | |
147 | urcu_die(errno); | |
148 | } | |
149 | } | |
bc6c15bb MD |
150 | } |
151 | ||
731ccb96 MD |
152 | /* |
153 | * Always called with rcu_registry lock held. Releases this lock between | |
154 | * iterations and grabs it again. Holds the lock when it returns. | |
155 | */ | |
708d89f0 MD |
156 | static void wait_for_readers(struct cds_list_head *input_readers, |
157 | struct cds_list_head *cur_snap_readers, | |
158 | struct cds_list_head *qsreaders) | |
9f1621ca | 159 | { |
9340c38d | 160 | unsigned int wait_loops = 0; |
4477a870 | 161 | struct urcu_qsbr_reader *index, *tmp; |
9f1621ca | 162 | |
9f1621ca | 163 | /* |
4477a870 | 164 | * Wait for each thread URCU_TLS(urcu_qsbr_reader).ctr to either |
f6b42f9c | 165 | * indicate quiescence (offline), or for them to observe the |
4477a870 | 166 | * current urcu_qsbr_gp.ctr value. |
9f1621ca | 167 | */ |
4d703340 | 168 | for (;;) { |
5e81fed7 MD |
169 | if (wait_loops < RCU_QS_ACTIVE_ATTEMPTS) |
170 | wait_loops++; | |
83a2c421 | 171 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4477a870 | 172 | uatomic_set(&urcu_qsbr_gp.futex, -1); |
83a2c421 PB |
173 | /* |
174 | * Write futex before write waiting (the other side | |
175 | * reads them in the opposite order). | |
176 | */ | |
177 | cmm_smp_wmb(); | |
708d89f0 | 178 | cds_list_for_each_entry(index, input_readers, node) { |
83a2c421 PB |
179 | _CMM_STORE_SHARED(index->waiting, 1); |
180 | } | |
4d703340 | 181 | /* Write futex before read reader_gp */ |
5481ddb3 | 182 | cmm_smp_mb(); |
4d703340 | 183 | } |
708d89f0 | 184 | cds_list_for_each_entry_safe(index, tmp, input_readers, node) { |
4477a870 MD |
185 | switch (urcu_qsbr_reader_state(&index->ctr)) { |
186 | case URCU_READER_ACTIVE_CURRENT: | |
708d89f0 MD |
187 | if (cur_snap_readers) { |
188 | cds_list_move(&index->node, | |
189 | cur_snap_readers); | |
190 | break; | |
191 | } | |
192 | /* Fall-through */ | |
4477a870 | 193 | case URCU_READER_INACTIVE: |
708d89f0 MD |
194 | cds_list_move(&index->node, qsreaders); |
195 | break; | |
4477a870 | 196 | case URCU_READER_ACTIVE_OLD: |
708d89f0 MD |
197 | /* |
198 | * Old snapshot. Leaving node in | |
199 | * input_readers will make us busy-loop | |
200 | * until the snapshot becomes current or | |
201 | * the reader becomes inactive. | |
202 | */ | |
203 | break; | |
204 | } | |
4d703340 | 205 | } |
bc6c15bb | 206 | |
708d89f0 | 207 | if (cds_list_empty(input_readers)) { |
83a2c421 | 208 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4d703340 | 209 | /* Read reader_gp before write futex */ |
5481ddb3 | 210 | cmm_smp_mb(); |
4477a870 | 211 | uatomic_set(&urcu_qsbr_gp.futex, 0); |
4d703340 MD |
212 | } |
213 | break; | |
214 | } else { | |
731ccb96 MD |
215 | /* Temporarily unlock the registry lock. */ |
216 | mutex_unlock(&rcu_registry_lock); | |
83a2c421 | 217 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4d703340 | 218 | wait_gp(); |
bc6c15bb | 219 | } else { |
9f1621ca | 220 | #ifndef HAS_INCOHERENT_CACHES |
06f22bdb | 221 | caa_cpu_relax(); |
9f1621ca | 222 | #else /* #ifndef HAS_INCOHERENT_CACHES */ |
5481ddb3 | 223 | cmm_smp_mb(); |
9f1621ca | 224 | #endif /* #else #ifndef HAS_INCOHERENT_CACHES */ |
bc6c15bb | 225 | } |
731ccb96 MD |
226 | /* Re-lock the registry lock before the next loop. */ |
227 | mutex_lock(&rcu_registry_lock); | |
bc6c15bb | 228 | } |
9f1621ca MD |
229 | } |
230 | } | |
231 | ||
47d2f29e MD |
232 | /* |
233 | * Using a two-subphases algorithm for architectures with smaller than 64-bit | |
234 | * long-size to ensure we do not encounter an overflow bug. | |
235 | */ | |
236 | ||
b39e1761 | 237 | #if (CAA_BITS_PER_LONG < 64) |
4477a870 | 238 | void urcu_qsbr_synchronize_rcu(void) |
47d2f29e | 239 | { |
708d89f0 MD |
240 | CDS_LIST_HEAD(cur_snap_readers); |
241 | CDS_LIST_HEAD(qsreaders); | |
bc49c323 | 242 | unsigned long was_online; |
bf6822a6 MD |
243 | DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING); |
244 | struct urcu_waiters waiters; | |
bc49c323 | 245 | |
4477a870 | 246 | was_online = urcu_qsbr_read_ongoing(); |
bc49c323 | 247 | |
47d2f29e | 248 | /* All threads should read qparity before accessing data structure |
27b940e7 PB |
249 | * where new ptr points to. In the "then" case, rcu_thread_offline |
250 | * includes a memory barrier. | |
251 | * | |
bc49c323 | 252 | * Mark the writer thread offline to make sure we don't wait for |
5e77fc1f PM |
253 | * our own quiescent state. This allows using synchronize_rcu() |
254 | * in threads registered as readers. | |
bc49c323 | 255 | */ |
27b940e7 | 256 | if (was_online) |
4477a870 | 257 | urcu_qsbr_thread_offline(); |
27b940e7 PB |
258 | else |
259 | cmm_smp_mb(); | |
bc49c323 | 260 | |
6362f68f | 261 | /* |
bf6822a6 | 262 | * Add ourself to gp_waiters queue of threads awaiting to wait |
6362f68f | 263 | * for a grace period. Proceed to perform the grace period only |
bf6822a6 | 264 | * if we are the first thread added into the queue. |
6362f68f | 265 | */ |
bf6822a6 MD |
266 | if (urcu_wait_add(&gp_waiters, &wait) != 0) { |
267 | /* Not first in queue: will be awakened by another thread. */ | |
268 | urcu_adaptative_busy_wait(&wait); | |
6362f68f MD |
269 | goto gp_end; |
270 | } | |
bf6822a6 MD |
271 | /* We won't need to wake ourself up */ |
272 | urcu_wait_set_state(&wait, URCU_WAIT_RUNNING); | |
6362f68f | 273 | |
6abb4bd5 | 274 | mutex_lock(&rcu_gp_lock); |
47d2f29e | 275 | |
6362f68f | 276 | /* |
bf6822a6 | 277 | * Move all waiters into our local queue. |
6362f68f | 278 | */ |
bf6822a6 | 279 | urcu_move_waiters(&waiters, &gp_waiters); |
6362f68f | 280 | |
731ccb96 MD |
281 | mutex_lock(&rcu_registry_lock); |
282 | ||
16aa9ee8 | 283 | if (cds_list_empty(®istry)) |
2dfb8b5e | 284 | goto out; |
47d2f29e MD |
285 | |
286 | /* | |
f6b42f9c | 287 | * Wait for readers to observe original parity or be quiescent. |
731ccb96 | 288 | * wait_for_readers() can release and grab again rcu_registry_lock |
f99c6e92 | 289 | * internally. |
47d2f29e | 290 | */ |
708d89f0 | 291 | wait_for_readers(®istry, &cur_snap_readers, &qsreaders); |
47d2f29e MD |
292 | |
293 | /* | |
f6b42f9c | 294 | * Must finish waiting for quiescent state for original parity |
4477a870 | 295 | * before committing next urcu_qsbr_gp.ctr update to memory. Failure |
f6b42f9c | 296 | * to do so could result in the writer waiting forever while new |
5e77fc1f | 297 | * readers are always accessing data (no progress). Enforce |
4477a870 MD |
298 | * compiler-order of load URCU_TLS(urcu_qsbr_reader).ctr before store |
299 | * to urcu_qsbr_gp.ctr. | |
47d2f29e | 300 | */ |
5481ddb3 | 301 | cmm_barrier(); |
47d2f29e | 302 | |
47d2f29e | 303 | /* |
5481ddb3 | 304 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the |
2dfb8b5e MD |
305 | * model easier to understand. It does not have a big performance impact |
306 | * anyway, given this is the write-side. | |
47d2f29e | 307 | */ |
5481ddb3 | 308 | cmm_smp_mb(); |
47d2f29e | 309 | |
f6b42f9c | 310 | /* Switch parity: 0 -> 1, 1 -> 0 */ |
4477a870 | 311 | CMM_STORE_SHARED(urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr ^ URCU_QSBR_GP_CTR); |
f6b42f9c | 312 | |
47d2f29e | 313 | /* |
4477a870 | 314 | * Must commit urcu_qsbr_gp.ctr update to memory before waiting for |
f6b42f9c MD |
315 | * quiescent state. Failure to do so could result in the writer |
316 | * waiting forever while new readers are always accessing data | |
4477a870 MD |
317 | * (no progress). Enforce compiler-order of store to urcu_qsbr_gp.ctr |
318 | * before load URCU_TLS(urcu_qsbr_reader).ctr. | |
47d2f29e | 319 | */ |
f6b42f9c MD |
320 | cmm_barrier(); |
321 | ||
322 | /* | |
323 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the | |
324 | * model easier to understand. It does not have a big performance impact | |
325 | * anyway, given this is the write-side. | |
326 | */ | |
327 | cmm_smp_mb(); | |
328 | ||
329 | /* | |
330 | * Wait for readers to observe new parity or be quiescent. | |
731ccb96 | 331 | * wait_for_readers() can release and grab again rcu_registry_lock |
f99c6e92 | 332 | * internally. |
f6b42f9c | 333 | */ |
708d89f0 MD |
334 | wait_for_readers(&cur_snap_readers, NULL, &qsreaders); |
335 | ||
336 | /* | |
337 | * Put quiescent reader list back into registry. | |
338 | */ | |
339 | cds_list_splice(&qsreaders, ®istry); | |
2dfb8b5e | 340 | out: |
731ccb96 | 341 | mutex_unlock(&rcu_registry_lock); |
6abb4bd5 | 342 | mutex_unlock(&rcu_gp_lock); |
bf6822a6 | 343 | urcu_wake_all_waiters(&waiters); |
6362f68f | 344 | gp_end: |
bc49c323 MD |
345 | /* |
346 | * Finish waiting for reader threads before letting the old ptr being | |
47d2f29e MD |
347 | * freed. |
348 | */ | |
bc49c323 | 349 | if (was_online) |
4477a870 | 350 | urcu_qsbr_thread_online(); |
27b940e7 PB |
351 | else |
352 | cmm_smp_mb(); | |
47d2f29e | 353 | } |
b39e1761 | 354 | #else /* !(CAA_BITS_PER_LONG < 64) */ |
4477a870 | 355 | void urcu_qsbr_synchronize_rcu(void) |
9f1621ca | 356 | { |
708d89f0 | 357 | CDS_LIST_HEAD(qsreaders); |
f0f7dbdd | 358 | unsigned long was_online; |
bf6822a6 MD |
359 | DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING); |
360 | struct urcu_waiters waiters; | |
ff2f67a0 | 361 | |
4477a870 | 362 | was_online = urcu_qsbr_read_ongoing(); |
ff2f67a0 MD |
363 | |
364 | /* | |
365 | * Mark the writer thread offline to make sure we don't wait for | |
5e77fc1f PM |
366 | * our own quiescent state. This allows using synchronize_rcu() |
367 | * in threads registered as readers. | |
ff2f67a0 | 368 | */ |
27b940e7 | 369 | if (was_online) |
4477a870 | 370 | urcu_qsbr_thread_offline(); |
27b940e7 PB |
371 | else |
372 | cmm_smp_mb(); | |
ff2f67a0 | 373 | |
6362f68f | 374 | /* |
bf6822a6 | 375 | * Add ourself to gp_waiters queue of threads awaiting to wait |
6362f68f | 376 | * for a grace period. Proceed to perform the grace period only |
bf6822a6 | 377 | * if we are the first thread added into the queue. |
6362f68f | 378 | */ |
bf6822a6 MD |
379 | if (urcu_wait_add(&gp_waiters, &wait) != 0) { |
380 | /* Not first in queue: will be awakened by another thread. */ | |
381 | urcu_adaptative_busy_wait(&wait); | |
6362f68f MD |
382 | goto gp_end; |
383 | } | |
bf6822a6 MD |
384 | /* We won't need to wake ourself up */ |
385 | urcu_wait_set_state(&wait, URCU_WAIT_RUNNING); | |
6362f68f | 386 | |
6abb4bd5 | 387 | mutex_lock(&rcu_gp_lock); |
6362f68f MD |
388 | |
389 | /* | |
bf6822a6 | 390 | * Move all waiters into our local queue. |
6362f68f | 391 | */ |
bf6822a6 | 392 | urcu_move_waiters(&waiters, &gp_waiters); |
6362f68f | 393 | |
731ccb96 MD |
394 | mutex_lock(&rcu_registry_lock); |
395 | ||
16aa9ee8 | 396 | if (cds_list_empty(®istry)) |
2dfb8b5e | 397 | goto out; |
f6b42f9c MD |
398 | |
399 | /* Increment current G.P. */ | |
4477a870 | 400 | CMM_STORE_SHARED(urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr + URCU_QSBR_GP_CTR); |
f6b42f9c MD |
401 | |
402 | /* | |
4477a870 | 403 | * Must commit urcu_qsbr_gp.ctr update to memory before waiting for |
f6b42f9c MD |
404 | * quiescent state. Failure to do so could result in the writer |
405 | * waiting forever while new readers are always accessing data | |
4477a870 MD |
406 | * (no progress). Enforce compiler-order of store to urcu_qsbr_gp.ctr |
407 | * before load URCU_TLS(urcu_qsbr_reader).ctr. | |
f6b42f9c MD |
408 | */ |
409 | cmm_barrier(); | |
410 | ||
411 | /* | |
412 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the | |
413 | * model easier to understand. It does not have a big performance impact | |
414 | * anyway, given this is the write-side. | |
415 | */ | |
416 | cmm_smp_mb(); | |
417 | ||
418 | /* | |
419 | * Wait for readers to observe new count of be quiescent. | |
731ccb96 | 420 | * wait_for_readers() can release and grab again rcu_registry_lock |
f99c6e92 | 421 | * internally. |
f6b42f9c | 422 | */ |
708d89f0 MD |
423 | wait_for_readers(®istry, NULL, &qsreaders); |
424 | ||
425 | /* | |
426 | * Put quiescent reader list back into registry. | |
427 | */ | |
428 | cds_list_splice(&qsreaders, ®istry); | |
2dfb8b5e | 429 | out: |
731ccb96 | 430 | mutex_unlock(&rcu_registry_lock); |
6abb4bd5 | 431 | mutex_unlock(&rcu_gp_lock); |
bf6822a6 | 432 | urcu_wake_all_waiters(&waiters); |
6362f68f | 433 | gp_end: |
ff2f67a0 | 434 | if (was_online) |
4477a870 | 435 | urcu_qsbr_thread_online(); |
27b940e7 PB |
436 | else |
437 | cmm_smp_mb(); | |
9f1621ca | 438 | } |
b39e1761 | 439 | #endif /* !(CAA_BITS_PER_LONG < 64) */ |
9f1621ca MD |
440 | |
441 | /* | |
442 | * library wrappers to be used by non-LGPL compatible source code. | |
443 | */ | |
444 | ||
4477a870 | 445 | void urcu_qsbr_read_lock(void) |
9f1621ca | 446 | { |
4477a870 | 447 | _urcu_qsbr_read_lock(); |
9f1621ca MD |
448 | } |
449 | ||
4477a870 | 450 | void urcu_qsbr_read_unlock(void) |
9f1621ca | 451 | { |
4477a870 | 452 | _urcu_qsbr_read_unlock(); |
9f1621ca MD |
453 | } |
454 | ||
4477a870 | 455 | int urcu_qsbr_read_ongoing(void) |
882f3357 | 456 | { |
4477a870 | 457 | return _urcu_qsbr_read_ongoing(); |
882f3357 | 458 | } |
4477a870 | 459 | void rcu_read_ongoing_qsbr(); |
882f3357 | 460 | |
4477a870 | 461 | void urcu_qsbr_quiescent_state(void) |
7ac06cef | 462 | { |
4477a870 | 463 | _urcu_qsbr_quiescent_state(); |
7ac06cef | 464 | } |
4477a870 | 465 | void rcu_quiescent_state_qsbr(); |
7ac06cef | 466 | |
4477a870 | 467 | void urcu_qsbr_thread_offline(void) |
7ac06cef | 468 | { |
4477a870 | 469 | _urcu_qsbr_thread_offline(); |
7ac06cef | 470 | } |
4477a870 | 471 | void rcu_thread_offline_qsbr(); |
7ac06cef | 472 | |
4477a870 | 473 | void urcu_qsbr_thread_online(void) |
7ac06cef | 474 | { |
4477a870 | 475 | _urcu_qsbr_thread_online(); |
7ac06cef MD |
476 | } |
477 | ||
4477a870 | 478 | void urcu_qsbr_register_thread(void) |
9f1621ca | 479 | { |
4477a870 | 480 | URCU_TLS(urcu_qsbr_reader).tid = pthread_self(); |
01477510 | 481 | urcu_posix_assert(URCU_TLS(urcu_qsbr_reader).ctr == 0); |
4f8e3380 | 482 | |
731ccb96 | 483 | mutex_lock(&rcu_registry_lock); |
01477510 | 484 | urcu_posix_assert(!URCU_TLS(urcu_qsbr_reader).registered); |
4477a870 MD |
485 | URCU_TLS(urcu_qsbr_reader).registered = 1; |
486 | cds_list_add(&URCU_TLS(urcu_qsbr_reader).node, ®istry); | |
731ccb96 | 487 | mutex_unlock(&rcu_registry_lock); |
4477a870 | 488 | _urcu_qsbr_thread_online(); |
9f1621ca MD |
489 | } |
490 | ||
4477a870 | 491 | void urcu_qsbr_unregister_thread(void) |
9f1621ca | 492 | { |
76f3022f MD |
493 | /* |
494 | * We have to make the thread offline otherwise we end up dealocking | |
495 | * with a waiting writer. | |
496 | */ | |
4477a870 | 497 | _urcu_qsbr_thread_offline(); |
01477510 | 498 | urcu_posix_assert(URCU_TLS(urcu_qsbr_reader).registered); |
4477a870 | 499 | URCU_TLS(urcu_qsbr_reader).registered = 0; |
731ccb96 | 500 | mutex_lock(&rcu_registry_lock); |
4477a870 | 501 | cds_list_del(&URCU_TLS(urcu_qsbr_reader).node); |
731ccb96 | 502 | mutex_unlock(&rcu_registry_lock); |
9f1621ca | 503 | } |
f6d18c64 | 504 | |
4477a870 | 505 | void urcu_qsbr_exit(void) |
f6d18c64 | 506 | { |
01cadde4 MD |
507 | /* |
508 | * Assertion disabled because call_rcu threads are now rcu | |
509 | * readers, and left running at exit. | |
01477510 | 510 | * urcu_posix_assert(cds_list_empty(®istry)); |
01cadde4 | 511 | */ |
f6d18c64 | 512 | } |
5e77fc1f | 513 | |
5e6b23a6 | 514 | DEFINE_RCU_FLAVOR(rcu_flavor); |
541d828d | 515 | |
5e77fc1f | 516 | #include "urcu-call-rcu-impl.h" |
0376e7b2 | 517 | #include "urcu-defer-impl.h" |