Commit | Line | Data |
---|---|---|
acdb82a2 MJ |
1 | // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
2 | // SPDX-FileCopyrightText: 2009 Paul E. McKenney, IBM Corporation. | |
3 | // | |
4 | // SPDX-License-Identifier: LGPL-2.1-or-later | |
5 | ||
9f1621ca | 6 | /* |
7ac06cef | 7 | * Userspace RCU QSBR library |
9f1621ca | 8 | * |
9f1621ca MD |
9 | * IBM's contributions to this file may be relicensed under LGPLv2 or later. |
10 | */ | |
11 | ||
e37faee1 | 12 | #define URCU_NO_COMPAT_IDENTIFIERS |
71c811bf | 13 | #define _LGPL_SOURCE |
9f1621ca MD |
14 | #include <stdio.h> |
15 | #include <pthread.h> | |
16 | #include <signal.h> | |
9f1621ca | 17 | #include <stdlib.h> |
6d841bc2 | 18 | #include <stdint.h> |
9f1621ca MD |
19 | #include <string.h> |
20 | #include <errno.h> | |
21 | #include <poll.h> | |
22 | ||
01477510 | 23 | #include <urcu/assert.h> |
4477a870 MD |
24 | #include <urcu/wfcqueue.h> |
25 | #include <urcu/map/urcu-qsbr.h> | |
727f819d | 26 | #define BUILD_QSBR_LIB |
4477a870 MD |
27 | #include <urcu/static/urcu-qsbr.h> |
28 | #include <urcu/pointer.h> | |
29 | #include <urcu/tls-compat.h> | |
71c811bf | 30 | |
4a6d7378 | 31 | #include "urcu-die.h" |
cba82d7b | 32 | #include "urcu-wait.h" |
ce28e67a | 33 | #include "urcu-utils.h" |
4a6d7378 | 34 | |
4477a870 | 35 | #define URCU_API_MAP |
9f1621ca | 36 | /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */ |
71c811bf | 37 | #undef _LGPL_SOURCE |
4477a870 | 38 | #include <urcu/urcu-qsbr.h> |
71c811bf | 39 | #define _LGPL_SOURCE |
9f1621ca | 40 | |
4477a870 | 41 | void __attribute__((destructor)) urcu_qsbr_exit(void); |
90f72b8c | 42 | static void urcu_call_rcu_exit(void); |
f6d18c64 | 43 | |
731ccb96 MD |
44 | /* |
45 | * rcu_gp_lock ensures mutual exclusion between threads calling | |
46 | * synchronize_rcu(). | |
47 | */ | |
6abb4bd5 | 48 | static pthread_mutex_t rcu_gp_lock = PTHREAD_MUTEX_INITIALIZER; |
731ccb96 MD |
49 | /* |
50 | * rcu_registry_lock ensures mutual exclusion between threads | |
51 | * registering and unregistering themselves to/from the registry, and | |
52 | * with threads reading that registry from synchronize_rcu(). However, | |
53 | * this lock is not held all the way through the completion of awaiting | |
54 | * for the grace period. It is sporadically released between iterations | |
55 | * on the registry. | |
56 | * rcu_registry_lock may nest inside rcu_gp_lock. | |
57 | */ | |
58 | static pthread_mutex_t rcu_registry_lock = PTHREAD_MUTEX_INITIALIZER; | |
4477a870 | 59 | struct urcu_gp urcu_qsbr_gp = { .ctr = URCU_QSBR_GP_ONLINE }; |
9f1621ca | 60 | |
408f6d92 PB |
61 | /* |
62 | * Active attempts to check for reader Q.S. before calling futex(). | |
63 | */ | |
64 | #define RCU_QS_ACTIVE_ATTEMPTS 100 | |
65 | ||
9f1621ca MD |
66 | /* |
67 | * Written to only by each individual reader. Read by both the reader and the | |
68 | * writers. | |
69 | */ | |
4477a870 | 70 | DEFINE_URCU_TLS(struct urcu_qsbr_reader, urcu_qsbr_reader); |
9f1621ca | 71 | |
16aa9ee8 | 72 | static CDS_LIST_HEAD(registry); |
9f1621ca | 73 | |
6362f68f | 74 | /* |
bf6822a6 | 75 | * Queue keeping threads awaiting to wait for a grace period. Contains |
6362f68f MD |
76 | * struct gp_waiters_thread objects. |
77 | */ | |
bf6822a6 | 78 | static DEFINE_URCU_WAIT_QUEUE(gp_waiters); |
6362f68f | 79 | |
6abb4bd5 | 80 | static void mutex_lock(pthread_mutex_t *mutex) |
9f1621ca MD |
81 | { |
82 | int ret; | |
83 | ||
84 | #ifndef DISTRUST_SIGNALS_EXTREME | |
6abb4bd5 | 85 | ret = pthread_mutex_lock(mutex); |
4a6d7378 MD |
86 | if (ret) |
87 | urcu_die(ret); | |
9f1621ca | 88 | #else /* #ifndef DISTRUST_SIGNALS_EXTREME */ |
6abb4bd5 | 89 | while ((ret = pthread_mutex_trylock(mutex)) != 0) { |
4a6d7378 MD |
90 | if (ret != EBUSY && ret != EINTR) |
91 | urcu_die(ret); | |
9f1621ca MD |
92 | poll(NULL,0,10); |
93 | } | |
94 | #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */ | |
95 | } | |
96 | ||
6abb4bd5 | 97 | static void mutex_unlock(pthread_mutex_t *mutex) |
9f1621ca MD |
98 | { |
99 | int ret; | |
100 | ||
6abb4bd5 | 101 | ret = pthread_mutex_unlock(mutex); |
4a6d7378 MD |
102 | if (ret) |
103 | urcu_die(ret); | |
9f1621ca MD |
104 | } |
105 | ||
bc6c15bb MD |
106 | /* |
107 | * synchronize_rcu() waiting. Single thread. | |
108 | */ | |
4d703340 | 109 | static void wait_gp(void) |
bc6c15bb | 110 | { |
4d703340 | 111 | /* Read reader_gp before read futex */ |
5481ddb3 | 112 | cmm_smp_rmb(); |
4974ad5f MD |
113 | while (uatomic_read(&urcu_qsbr_gp.futex) == -1) { |
114 | if (!futex_noasync(&urcu_qsbr_gp.futex, FUTEX_WAIT, -1, NULL, NULL, 0)) { | |
115 | /* | |
116 | * Prior queued wakeups queued by unrelated code | |
117 | * using the same address can cause futex wait to | |
118 | * return 0 even through the futex value is still | |
119 | * -1 (spurious wakeups). Check the value again | |
120 | * in user-space to validate whether it really | |
121 | * differs from -1. | |
122 | */ | |
123 | continue; | |
124 | } | |
b0a841b4 | 125 | switch (errno) { |
4974ad5f | 126 | case EAGAIN: |
b0a841b4 MD |
127 | /* Value already changed. */ |
128 | return; | |
129 | case EINTR: | |
130 | /* Retry if interrupted by signal. */ | |
4974ad5f | 131 | break; /* Get out of switch. Check again. */ |
b0a841b4 MD |
132 | default: |
133 | /* Unexpected error. */ | |
134 | urcu_die(errno); | |
135 | } | |
136 | } | |
bc6c15bb MD |
137 | } |
138 | ||
731ccb96 MD |
139 | /* |
140 | * Always called with rcu_registry lock held. Releases this lock between | |
141 | * iterations and grabs it again. Holds the lock when it returns. | |
142 | */ | |
708d89f0 MD |
143 | static void wait_for_readers(struct cds_list_head *input_readers, |
144 | struct cds_list_head *cur_snap_readers, | |
145 | struct cds_list_head *qsreaders) | |
9f1621ca | 146 | { |
9340c38d | 147 | unsigned int wait_loops = 0; |
4477a870 | 148 | struct urcu_qsbr_reader *index, *tmp; |
9f1621ca | 149 | |
9f1621ca | 150 | /* |
4477a870 | 151 | * Wait for each thread URCU_TLS(urcu_qsbr_reader).ctr to either |
f6b42f9c | 152 | * indicate quiescence (offline), or for them to observe the |
4477a870 | 153 | * current urcu_qsbr_gp.ctr value. |
9f1621ca | 154 | */ |
4d703340 | 155 | for (;;) { |
5e81fed7 MD |
156 | if (wait_loops < RCU_QS_ACTIVE_ATTEMPTS) |
157 | wait_loops++; | |
83a2c421 | 158 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4477a870 | 159 | uatomic_set(&urcu_qsbr_gp.futex, -1); |
83a2c421 PB |
160 | /* |
161 | * Write futex before write waiting (the other side | |
162 | * reads them in the opposite order). | |
163 | */ | |
164 | cmm_smp_wmb(); | |
708d89f0 | 165 | cds_list_for_each_entry(index, input_readers, node) { |
83a2c421 PB |
166 | _CMM_STORE_SHARED(index->waiting, 1); |
167 | } | |
4d703340 | 168 | /* Write futex before read reader_gp */ |
5481ddb3 | 169 | cmm_smp_mb(); |
4d703340 | 170 | } |
708d89f0 | 171 | cds_list_for_each_entry_safe(index, tmp, input_readers, node) { |
4477a870 MD |
172 | switch (urcu_qsbr_reader_state(&index->ctr)) { |
173 | case URCU_READER_ACTIVE_CURRENT: | |
708d89f0 MD |
174 | if (cur_snap_readers) { |
175 | cds_list_move(&index->node, | |
176 | cur_snap_readers); | |
177 | break; | |
178 | } | |
179 | /* Fall-through */ | |
4477a870 | 180 | case URCU_READER_INACTIVE: |
708d89f0 MD |
181 | cds_list_move(&index->node, qsreaders); |
182 | break; | |
4477a870 | 183 | case URCU_READER_ACTIVE_OLD: |
708d89f0 MD |
184 | /* |
185 | * Old snapshot. Leaving node in | |
186 | * input_readers will make us busy-loop | |
187 | * until the snapshot becomes current or | |
188 | * the reader becomes inactive. | |
189 | */ | |
190 | break; | |
191 | } | |
4d703340 | 192 | } |
bc6c15bb | 193 | |
708d89f0 | 194 | if (cds_list_empty(input_readers)) { |
83a2c421 | 195 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4d703340 | 196 | /* Read reader_gp before write futex */ |
5481ddb3 | 197 | cmm_smp_mb(); |
4477a870 | 198 | uatomic_set(&urcu_qsbr_gp.futex, 0); |
4d703340 MD |
199 | } |
200 | break; | |
201 | } else { | |
731ccb96 MD |
202 | /* Temporarily unlock the registry lock. */ |
203 | mutex_unlock(&rcu_registry_lock); | |
83a2c421 | 204 | if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) { |
4d703340 | 205 | wait_gp(); |
bc6c15bb | 206 | } else { |
9f1621ca | 207 | #ifndef HAS_INCOHERENT_CACHES |
06f22bdb | 208 | caa_cpu_relax(); |
9f1621ca | 209 | #else /* #ifndef HAS_INCOHERENT_CACHES */ |
5481ddb3 | 210 | cmm_smp_mb(); |
9f1621ca | 211 | #endif /* #else #ifndef HAS_INCOHERENT_CACHES */ |
bc6c15bb | 212 | } |
731ccb96 MD |
213 | /* Re-lock the registry lock before the next loop. */ |
214 | mutex_lock(&rcu_registry_lock); | |
bc6c15bb | 215 | } |
9f1621ca MD |
216 | } |
217 | } | |
218 | ||
47d2f29e MD |
219 | /* |
220 | * Using a two-subphases algorithm for architectures with smaller than 64-bit | |
221 | * long-size to ensure we do not encounter an overflow bug. | |
222 | */ | |
223 | ||
b39e1761 | 224 | #if (CAA_BITS_PER_LONG < 64) |
4477a870 | 225 | void urcu_qsbr_synchronize_rcu(void) |
47d2f29e | 226 | { |
708d89f0 MD |
227 | CDS_LIST_HEAD(cur_snap_readers); |
228 | CDS_LIST_HEAD(qsreaders); | |
bc49c323 | 229 | unsigned long was_online; |
bf6822a6 MD |
230 | DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING); |
231 | struct urcu_waiters waiters; | |
bc49c323 | 232 | |
4477a870 | 233 | was_online = urcu_qsbr_read_ongoing(); |
bc49c323 | 234 | |
47d2f29e | 235 | /* All threads should read qparity before accessing data structure |
27b940e7 PB |
236 | * where new ptr points to. In the "then" case, rcu_thread_offline |
237 | * includes a memory barrier. | |
238 | * | |
bc49c323 | 239 | * Mark the writer thread offline to make sure we don't wait for |
5e77fc1f PM |
240 | * our own quiescent state. This allows using synchronize_rcu() |
241 | * in threads registered as readers. | |
bc49c323 | 242 | */ |
27b940e7 | 243 | if (was_online) |
4477a870 | 244 | urcu_qsbr_thread_offline(); |
27b940e7 PB |
245 | else |
246 | cmm_smp_mb(); | |
bc49c323 | 247 | |
6362f68f | 248 | /* |
bf6822a6 | 249 | * Add ourself to gp_waiters queue of threads awaiting to wait |
6362f68f | 250 | * for a grace period. Proceed to perform the grace period only |
bf6822a6 | 251 | * if we are the first thread added into the queue. |
6362f68f | 252 | */ |
bf6822a6 MD |
253 | if (urcu_wait_add(&gp_waiters, &wait) != 0) { |
254 | /* Not first in queue: will be awakened by another thread. */ | |
255 | urcu_adaptative_busy_wait(&wait); | |
6362f68f MD |
256 | goto gp_end; |
257 | } | |
bf6822a6 MD |
258 | /* We won't need to wake ourself up */ |
259 | urcu_wait_set_state(&wait, URCU_WAIT_RUNNING); | |
6362f68f | 260 | |
6abb4bd5 | 261 | mutex_lock(&rcu_gp_lock); |
47d2f29e | 262 | |
6362f68f | 263 | /* |
bf6822a6 | 264 | * Move all waiters into our local queue. |
6362f68f | 265 | */ |
bf6822a6 | 266 | urcu_move_waiters(&waiters, &gp_waiters); |
6362f68f | 267 | |
731ccb96 MD |
268 | mutex_lock(&rcu_registry_lock); |
269 | ||
16aa9ee8 | 270 | if (cds_list_empty(®istry)) |
2dfb8b5e | 271 | goto out; |
47d2f29e MD |
272 | |
273 | /* | |
f6b42f9c | 274 | * Wait for readers to observe original parity or be quiescent. |
731ccb96 | 275 | * wait_for_readers() can release and grab again rcu_registry_lock |
f99c6e92 | 276 | * internally. |
47d2f29e | 277 | */ |
708d89f0 | 278 | wait_for_readers(®istry, &cur_snap_readers, &qsreaders); |
47d2f29e MD |
279 | |
280 | /* | |
f6b42f9c | 281 | * Must finish waiting for quiescent state for original parity |
4477a870 | 282 | * before committing next urcu_qsbr_gp.ctr update to memory. Failure |
f6b42f9c | 283 | * to do so could result in the writer waiting forever while new |
5e77fc1f | 284 | * readers are always accessing data (no progress). Enforce |
4477a870 MD |
285 | * compiler-order of load URCU_TLS(urcu_qsbr_reader).ctr before store |
286 | * to urcu_qsbr_gp.ctr. | |
47d2f29e | 287 | */ |
5481ddb3 | 288 | cmm_barrier(); |
47d2f29e | 289 | |
47d2f29e | 290 | /* |
5481ddb3 | 291 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the |
2dfb8b5e MD |
292 | * model easier to understand. It does not have a big performance impact |
293 | * anyway, given this is the write-side. | |
47d2f29e | 294 | */ |
5481ddb3 | 295 | cmm_smp_mb(); |
47d2f29e | 296 | |
f6b42f9c | 297 | /* Switch parity: 0 -> 1, 1 -> 0 */ |
4477a870 | 298 | CMM_STORE_SHARED(urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr ^ URCU_QSBR_GP_CTR); |
f6b42f9c | 299 | |
47d2f29e | 300 | /* |
4477a870 | 301 | * Must commit urcu_qsbr_gp.ctr update to memory before waiting for |
f6b42f9c MD |
302 | * quiescent state. Failure to do so could result in the writer |
303 | * waiting forever while new readers are always accessing data | |
4477a870 MD |
304 | * (no progress). Enforce compiler-order of store to urcu_qsbr_gp.ctr |
305 | * before load URCU_TLS(urcu_qsbr_reader).ctr. | |
47d2f29e | 306 | */ |
f6b42f9c MD |
307 | cmm_barrier(); |
308 | ||
309 | /* | |
310 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the | |
311 | * model easier to understand. It does not have a big performance impact | |
312 | * anyway, given this is the write-side. | |
313 | */ | |
314 | cmm_smp_mb(); | |
315 | ||
316 | /* | |
317 | * Wait for readers to observe new parity or be quiescent. | |
731ccb96 | 318 | * wait_for_readers() can release and grab again rcu_registry_lock |
f99c6e92 | 319 | * internally. |
f6b42f9c | 320 | */ |
708d89f0 MD |
321 | wait_for_readers(&cur_snap_readers, NULL, &qsreaders); |
322 | ||
323 | /* | |
324 | * Put quiescent reader list back into registry. | |
325 | */ | |
326 | cds_list_splice(&qsreaders, ®istry); | |
2dfb8b5e | 327 | out: |
731ccb96 | 328 | mutex_unlock(&rcu_registry_lock); |
6abb4bd5 | 329 | mutex_unlock(&rcu_gp_lock); |
bf6822a6 | 330 | urcu_wake_all_waiters(&waiters); |
6362f68f | 331 | gp_end: |
bc49c323 MD |
332 | /* |
333 | * Finish waiting for reader threads before letting the old ptr being | |
47d2f29e MD |
334 | * freed. |
335 | */ | |
bc49c323 | 336 | if (was_online) |
4477a870 | 337 | urcu_qsbr_thread_online(); |
27b940e7 PB |
338 | else |
339 | cmm_smp_mb(); | |
47d2f29e | 340 | } |
b39e1761 | 341 | #else /* !(CAA_BITS_PER_LONG < 64) */ |
4477a870 | 342 | void urcu_qsbr_synchronize_rcu(void) |
9f1621ca | 343 | { |
708d89f0 | 344 | CDS_LIST_HEAD(qsreaders); |
f0f7dbdd | 345 | unsigned long was_online; |
bf6822a6 MD |
346 | DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING); |
347 | struct urcu_waiters waiters; | |
ff2f67a0 | 348 | |
4477a870 | 349 | was_online = urcu_qsbr_read_ongoing(); |
ff2f67a0 MD |
350 | |
351 | /* | |
352 | * Mark the writer thread offline to make sure we don't wait for | |
5e77fc1f PM |
353 | * our own quiescent state. This allows using synchronize_rcu() |
354 | * in threads registered as readers. | |
ff2f67a0 | 355 | */ |
27b940e7 | 356 | if (was_online) |
4477a870 | 357 | urcu_qsbr_thread_offline(); |
27b940e7 PB |
358 | else |
359 | cmm_smp_mb(); | |
ff2f67a0 | 360 | |
6362f68f | 361 | /* |
bf6822a6 | 362 | * Add ourself to gp_waiters queue of threads awaiting to wait |
6362f68f | 363 | * for a grace period. Proceed to perform the grace period only |
bf6822a6 | 364 | * if we are the first thread added into the queue. |
6362f68f | 365 | */ |
bf6822a6 MD |
366 | if (urcu_wait_add(&gp_waiters, &wait) != 0) { |
367 | /* Not first in queue: will be awakened by another thread. */ | |
368 | urcu_adaptative_busy_wait(&wait); | |
6362f68f MD |
369 | goto gp_end; |
370 | } | |
bf6822a6 MD |
371 | /* We won't need to wake ourself up */ |
372 | urcu_wait_set_state(&wait, URCU_WAIT_RUNNING); | |
6362f68f | 373 | |
6abb4bd5 | 374 | mutex_lock(&rcu_gp_lock); |
6362f68f MD |
375 | |
376 | /* | |
bf6822a6 | 377 | * Move all waiters into our local queue. |
6362f68f | 378 | */ |
bf6822a6 | 379 | urcu_move_waiters(&waiters, &gp_waiters); |
6362f68f | 380 | |
731ccb96 MD |
381 | mutex_lock(&rcu_registry_lock); |
382 | ||
16aa9ee8 | 383 | if (cds_list_empty(®istry)) |
2dfb8b5e | 384 | goto out; |
f6b42f9c MD |
385 | |
386 | /* Increment current G.P. */ | |
4477a870 | 387 | CMM_STORE_SHARED(urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr + URCU_QSBR_GP_CTR); |
f6b42f9c MD |
388 | |
389 | /* | |
4477a870 | 390 | * Must commit urcu_qsbr_gp.ctr update to memory before waiting for |
f6b42f9c MD |
391 | * quiescent state. Failure to do so could result in the writer |
392 | * waiting forever while new readers are always accessing data | |
4477a870 MD |
393 | * (no progress). Enforce compiler-order of store to urcu_qsbr_gp.ctr |
394 | * before load URCU_TLS(urcu_qsbr_reader).ctr. | |
f6b42f9c MD |
395 | */ |
396 | cmm_barrier(); | |
397 | ||
398 | /* | |
399 | * Adding a cmm_smp_mb() which is _not_ formally required, but makes the | |
400 | * model easier to understand. It does not have a big performance impact | |
401 | * anyway, given this is the write-side. | |
402 | */ | |
403 | cmm_smp_mb(); | |
404 | ||
405 | /* | |
406 | * Wait for readers to observe new count of be quiescent. | |
731ccb96 | 407 | * wait_for_readers() can release and grab again rcu_registry_lock |
f99c6e92 | 408 | * internally. |
f6b42f9c | 409 | */ |
708d89f0 MD |
410 | wait_for_readers(®istry, NULL, &qsreaders); |
411 | ||
412 | /* | |
413 | * Put quiescent reader list back into registry. | |
414 | */ | |
415 | cds_list_splice(&qsreaders, ®istry); | |
2dfb8b5e | 416 | out: |
731ccb96 | 417 | mutex_unlock(&rcu_registry_lock); |
6abb4bd5 | 418 | mutex_unlock(&rcu_gp_lock); |
bf6822a6 | 419 | urcu_wake_all_waiters(&waiters); |
6362f68f | 420 | gp_end: |
ff2f67a0 | 421 | if (was_online) |
4477a870 | 422 | urcu_qsbr_thread_online(); |
27b940e7 PB |
423 | else |
424 | cmm_smp_mb(); | |
9f1621ca | 425 | } |
b39e1761 | 426 | #endif /* !(CAA_BITS_PER_LONG < 64) */ |
9f1621ca MD |
427 | |
428 | /* | |
429 | * library wrappers to be used by non-LGPL compatible source code. | |
430 | */ | |
431 | ||
4477a870 | 432 | void urcu_qsbr_read_lock(void) |
9f1621ca | 433 | { |
4477a870 | 434 | _urcu_qsbr_read_lock(); |
9f1621ca MD |
435 | } |
436 | ||
4477a870 | 437 | void urcu_qsbr_read_unlock(void) |
9f1621ca | 438 | { |
4477a870 | 439 | _urcu_qsbr_read_unlock(); |
9f1621ca MD |
440 | } |
441 | ||
4477a870 | 442 | int urcu_qsbr_read_ongoing(void) |
882f3357 | 443 | { |
4477a870 | 444 | return _urcu_qsbr_read_ongoing(); |
882f3357 | 445 | } |
4477a870 | 446 | void rcu_read_ongoing_qsbr(); |
882f3357 | 447 | |
4477a870 | 448 | void urcu_qsbr_quiescent_state(void) |
7ac06cef | 449 | { |
4477a870 | 450 | _urcu_qsbr_quiescent_state(); |
7ac06cef | 451 | } |
4477a870 | 452 | void rcu_quiescent_state_qsbr(); |
7ac06cef | 453 | |
4477a870 | 454 | void urcu_qsbr_thread_offline(void) |
7ac06cef | 455 | { |
4477a870 | 456 | _urcu_qsbr_thread_offline(); |
7ac06cef | 457 | } |
4477a870 | 458 | void rcu_thread_offline_qsbr(); |
7ac06cef | 459 | |
4477a870 | 460 | void urcu_qsbr_thread_online(void) |
7ac06cef | 461 | { |
4477a870 | 462 | _urcu_qsbr_thread_online(); |
7ac06cef MD |
463 | } |
464 | ||
4477a870 | 465 | void urcu_qsbr_register_thread(void) |
9f1621ca | 466 | { |
4477a870 | 467 | URCU_TLS(urcu_qsbr_reader).tid = pthread_self(); |
01477510 | 468 | urcu_posix_assert(URCU_TLS(urcu_qsbr_reader).ctr == 0); |
4f8e3380 | 469 | |
731ccb96 | 470 | mutex_lock(&rcu_registry_lock); |
01477510 | 471 | urcu_posix_assert(!URCU_TLS(urcu_qsbr_reader).registered); |
4477a870 MD |
472 | URCU_TLS(urcu_qsbr_reader).registered = 1; |
473 | cds_list_add(&URCU_TLS(urcu_qsbr_reader).node, ®istry); | |
731ccb96 | 474 | mutex_unlock(&rcu_registry_lock); |
4477a870 | 475 | _urcu_qsbr_thread_online(); |
9f1621ca MD |
476 | } |
477 | ||
4477a870 | 478 | void urcu_qsbr_unregister_thread(void) |
9f1621ca | 479 | { |
76f3022f MD |
480 | /* |
481 | * We have to make the thread offline otherwise we end up dealocking | |
482 | * with a waiting writer. | |
483 | */ | |
4477a870 | 484 | _urcu_qsbr_thread_offline(); |
01477510 | 485 | urcu_posix_assert(URCU_TLS(urcu_qsbr_reader).registered); |
4477a870 | 486 | URCU_TLS(urcu_qsbr_reader).registered = 0; |
731ccb96 | 487 | mutex_lock(&rcu_registry_lock); |
4477a870 | 488 | cds_list_del(&URCU_TLS(urcu_qsbr_reader).node); |
731ccb96 | 489 | mutex_unlock(&rcu_registry_lock); |
9f1621ca | 490 | } |
f6d18c64 | 491 | |
4477a870 | 492 | void urcu_qsbr_exit(void) |
f6d18c64 | 493 | { |
01cadde4 MD |
494 | /* |
495 | * Assertion disabled because call_rcu threads are now rcu | |
496 | * readers, and left running at exit. | |
01477510 | 497 | * urcu_posix_assert(cds_list_empty(®istry)); |
01cadde4 | 498 | */ |
90f72b8c | 499 | urcu_call_rcu_exit(); |
f6d18c64 | 500 | } |
5e77fc1f | 501 | |
5e6b23a6 | 502 | DEFINE_RCU_FLAVOR(rcu_flavor); |
541d828d | 503 | |
5e77fc1f | 504 | #include "urcu-call-rcu-impl.h" |
0376e7b2 | 505 | #include "urcu-defer-impl.h" |
111bda8f | 506 | #include "urcu-poll-impl.h" |