+// SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+// SPDX-FileCopyrightText: 2009 Paul E. McKenney, IBM Corporation.
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
/*
- * urcu-qsbr.c
- *
* Userspace RCU QSBR library
*
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
* IBM's contributions to this file may be relicensed under LGPLv2 or later.
*/
+#define URCU_NO_COMPAT_IDENTIFIERS
#define _LGPL_SOURCE
#include <stdio.h>
#include <pthread.h>
#include <signal.h>
-#include <assert.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <poll.h>
+#include <urcu/annotate.h>
+#include <urcu/assert.h>
#include <urcu/wfcqueue.h>
#include <urcu/map/urcu-qsbr.h>
#define BUILD_QSBR_LIB
#define _LGPL_SOURCE
void __attribute__((destructor)) urcu_qsbr_exit(void);
+static void urcu_call_rcu_exit(void);
/*
* rcu_gp_lock ensures mutual exclusion between threads calling
*/
static pthread_mutex_t rcu_registry_lock = PTHREAD_MUTEX_INITIALIZER;
struct urcu_gp urcu_qsbr_gp = { .ctr = URCU_QSBR_GP_ONLINE };
-URCU_ATTR_ALIAS("urcu_qsbr_gp") extern struct urcu_gp rcu_gp_qsbr;
/*
* Active attempts to check for reader Q.S. before calling futex().
* writers.
*/
DEFINE_URCU_TLS(struct urcu_qsbr_reader, urcu_qsbr_reader);
-DEFINE_URCU_TLS_ALIAS(struct urcu_qsbr_reader, urcu_qsbr_reader, rcu_reader_qsbr);
static CDS_LIST_HEAD(registry);
{
/* Read reader_gp before read futex */
cmm_smp_rmb();
- if (uatomic_read(&urcu_qsbr_gp.futex) != -1)
- return;
- while (futex_noasync(&urcu_qsbr_gp.futex, FUTEX_WAIT, -1,
- NULL, NULL, 0)) {
+ while (uatomic_read(&urcu_qsbr_gp.futex) == -1) {
+ if (!futex_noasync(&urcu_qsbr_gp.futex, FUTEX_WAIT, -1, NULL, NULL, 0)) {
+ /*
+ * Prior queued wakeups queued by unrelated code
+ * using the same address can cause futex wait to
+ * return 0 even through the futex value is still
+ * -1 (spurious wakeups). Check the value again
+ * in user-space to validate whether it really
+ * differs from -1.
+ */
+ continue;
+ }
switch (errno) {
- case EWOULDBLOCK:
+ case EAGAIN:
/* Value already changed. */
return;
case EINTR:
/* Retry if interrupted by signal. */
- break; /* Get out of switch. */
+ break; /* Get out of switch. Check again. */
default:
/* Unexpected error. */
urcu_die(errno);
*/
static void wait_for_readers(struct cds_list_head *input_readers,
struct cds_list_head *cur_snap_readers,
- struct cds_list_head *qsreaders)
+ struct cds_list_head *qsreaders,
+ cmm_annotate_t *group)
{
unsigned int wait_loops = 0;
struct urcu_qsbr_reader *index, *tmp;
cmm_smp_mb();
}
cds_list_for_each_entry_safe(index, tmp, input_readers, node) {
- switch (urcu_qsbr_reader_state(&index->ctr)) {
+ switch (urcu_qsbr_reader_state(&index->ctr, group)) {
case URCU_READER_ACTIVE_CURRENT:
if (cur_snap_readers) {
cds_list_move(&index->node,
if (cds_list_empty(input_readers)) {
if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) {
/* Read reader_gp before write futex */
- cmm_smp_mb();
- uatomic_set(&urcu_qsbr_gp.futex, 0);
+ uatomic_store(&urcu_qsbr_gp.futex, 0, CMM_RELEASE);
}
break;
} else {
#if (CAA_BITS_PER_LONG < 64)
void urcu_qsbr_synchronize_rcu(void)
{
+ cmm_annotate_define(acquire_group);
+ cmm_annotate_define(release_group);
CDS_LIST_HEAD(cur_snap_readers);
CDS_LIST_HEAD(qsreaders);
unsigned long was_online;
urcu_qsbr_thread_offline();
else
cmm_smp_mb();
+ cmm_annotate_group_mb_release(&release_group);
/*
* Add ourself to gp_waiters queue of threads awaiting to wait
/*
* Wait for readers to observe original parity or be quiescent.
* wait_for_readers() can release and grab again rcu_registry_lock
- * interally.
+ * internally.
*/
- wait_for_readers(®istry, &cur_snap_readers, &qsreaders);
+ wait_for_readers(®istry, &cur_snap_readers, &qsreaders, &acquire_group);
/*
* Must finish waiting for quiescent state for original parity
cmm_smp_mb();
/* Switch parity: 0 -> 1, 1 -> 0 */
- CMM_STORE_SHARED(urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr ^ URCU_QSBR_GP_CTR);
+ cmm_annotate_group_mem_release(&release_group, &urcu_qsbr_gp.ctr);
+ uatomic_store(&urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr ^ URCU_QSBR_GP_CTR, CMM_RELAXED);
/*
* Must commit urcu_qsbr_gp.ctr update to memory before waiting for
/*
* Wait for readers to observe new parity or be quiescent.
* wait_for_readers() can release and grab again rcu_registry_lock
- * interally.
+ * internally.
*/
- wait_for_readers(&cur_snap_readers, NULL, &qsreaders);
+ wait_for_readers(&cur_snap_readers, NULL, &qsreaders, &acquire_group);
/*
* Put quiescent reader list back into registry.
* Finish waiting for reader threads before letting the old ptr being
* freed.
*/
+ cmm_annotate_group_mb_acquire(&acquire_group);
+
if (was_online)
urcu_qsbr_thread_online();
else
#else /* !(CAA_BITS_PER_LONG < 64) */
void urcu_qsbr_synchronize_rcu(void)
{
+ cmm_annotate_define(acquire_group);
+ cmm_annotate_define(release_group);
CDS_LIST_HEAD(qsreaders);
unsigned long was_online;
DEFINE_URCU_WAIT_NODE(wait, URCU_WAIT_WAITING);
urcu_qsbr_thread_offline();
else
cmm_smp_mb();
+ cmm_annotate_group_mb_release(&release_group);
/*
* Add ourself to gp_waiters queue of threads awaiting to wait
goto out;
/* Increment current G.P. */
- CMM_STORE_SHARED(urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr + URCU_QSBR_GP_CTR);
+ cmm_annotate_group_mem_release(&release_group, &urcu_qsbr_gp.ctr);
+ uatomic_store(&urcu_qsbr_gp.ctr, urcu_qsbr_gp.ctr + URCU_QSBR_GP_CTR, CMM_RELAXED);
/*
* Must commit urcu_qsbr_gp.ctr update to memory before waiting for
/*
* Wait for readers to observe new count of be quiescent.
* wait_for_readers() can release and grab again rcu_registry_lock
- * interally.
+ * internally.
*/
- wait_for_readers(®istry, NULL, &qsreaders);
+ wait_for_readers(®istry, NULL, &qsreaders, &acquire_group);
/*
* Put quiescent reader list back into registry.
urcu_qsbr_thread_online();
else
cmm_smp_mb();
+
+ cmm_annotate_group_mb_acquire(&acquire_group);
}
#endif /* !(CAA_BITS_PER_LONG < 64) */
-URCU_ATTR_ALIAS("urcu_qsbr_synchronize_rcu")
-void synchronize_rcu_qsbr();
/*
* library wrappers to be used by non-LGPL compatible source code.
{
_urcu_qsbr_read_lock();
}
-URCU_ATTR_ALIAS("urcu_qsbr_read_lock") void rcu_read_lock_qsbr();
void urcu_qsbr_read_unlock(void)
{
_urcu_qsbr_read_unlock();
}
-URCU_ATTR_ALIAS("urcu_qsbr_read_unlock") void rcu_read_unlock_qsbr();
int urcu_qsbr_read_ongoing(void)
{
return _urcu_qsbr_read_ongoing();
}
-URCU_ATTR_ALIAS("urcu_qsbr_read_ongoing")
void rcu_read_ongoing_qsbr();
void urcu_qsbr_quiescent_state(void)
{
_urcu_qsbr_quiescent_state();
}
-URCU_ATTR_ALIAS("urcu_qsbr_quiescent_state")
void rcu_quiescent_state_qsbr();
void urcu_qsbr_thread_offline(void)
{
_urcu_qsbr_thread_offline();
}
-URCU_ATTR_ALIAS("urcu_qsbr_thread_offline")
void rcu_thread_offline_qsbr();
void urcu_qsbr_thread_online(void)
{
_urcu_qsbr_thread_online();
}
-URCU_ATTR_ALIAS("urcu_qsbr_thread_online")
-void rcu_thread_online_qsbr();
void urcu_qsbr_register_thread(void)
{
URCU_TLS(urcu_qsbr_reader).tid = pthread_self();
- assert(URCU_TLS(urcu_qsbr_reader).ctr == 0);
+ urcu_posix_assert(URCU_TLS(urcu_qsbr_reader).ctr == 0);
mutex_lock(&rcu_registry_lock);
- assert(!URCU_TLS(urcu_qsbr_reader).registered);
+ urcu_posix_assert(!URCU_TLS(urcu_qsbr_reader).registered);
URCU_TLS(urcu_qsbr_reader).registered = 1;
cds_list_add(&URCU_TLS(urcu_qsbr_reader).node, ®istry);
mutex_unlock(&rcu_registry_lock);
_urcu_qsbr_thread_online();
}
-URCU_ATTR_ALIAS("urcu_qsbr_register_thread")
-void rcu_register_thread_qsbr();
void urcu_qsbr_unregister_thread(void)
{
* with a waiting writer.
*/
_urcu_qsbr_thread_offline();
- assert(URCU_TLS(urcu_qsbr_reader).registered);
+ urcu_posix_assert(URCU_TLS(urcu_qsbr_reader).registered);
URCU_TLS(urcu_qsbr_reader).registered = 0;
mutex_lock(&rcu_registry_lock);
cds_list_del(&URCU_TLS(urcu_qsbr_reader).node);
mutex_unlock(&rcu_registry_lock);
}
-URCU_ATTR_ALIAS("urcu_qsbr_unregister_thread")
-void rcu_unregister_thread_qsbr();
void urcu_qsbr_exit(void)
{
/*
* Assertion disabled because call_rcu threads are now rcu
* readers, and left running at exit.
- * assert(cds_list_empty(®istry));
+ * urcu_posix_assert(cds_list_empty(®istry));
*/
+ urcu_call_rcu_exit();
}
-URCU_ATTR_ALIAS("urcu_qsbr_exit") void rcu_exit_qsbr();
DEFINE_RCU_FLAVOR(rcu_flavor);
-DEFINE_RCU_FLAVOR_ALIAS(rcu_flavor, alias_rcu_flavor);
#include "urcu-call-rcu-impl.h"
#include "urcu-defer-impl.h"
+#include "urcu-poll-impl.h"
projects / urcu.git / blobdiff