* IBM's contributions to this file may be relicensed under LGPLv2 or later.
*/
+#define URCU_NO_COMPAT_IDENTIFIERS
#define _BSD_SOURCE
#define _LGPL_SOURCE
#define _DEFAULT_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 <stdbool.h>
#include <poll.h>
-#include "urcu/arch.h"
-#include "urcu/wfcqueue.h"
-#include "urcu/map/urcu.h"
-#include "urcu/static/urcu.h"
-#include "urcu-pointer.h"
-#include "urcu/tls-compat.h"
+#include <urcu/config.h>
+#include <urcu/assert.h>
+#include <urcu/arch.h>
+#include <urcu/wfcqueue.h>
+#include <urcu/map/urcu.h>
+#include <urcu/static/urcu.h>
+#include <urcu/pointer.h>
+#include <urcu/tls-compat.h>
#include "urcu-die.h"
#include "urcu-wait.h"
+#include "urcu-utils.h"
+#define URCU_API_MAP
/* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
#undef _LGPL_SOURCE
-#include "urcu.h"
+#include <urcu/urcu.h>
#define _LGPL_SOURCE
/*
#endif
enum membarrier_cmd {
- MEMBARRIER_CMD_QUERY = 0,
- MEMBARRIER_CMD_SHARED = (1 << 0),
+ MEMBARRIER_CMD_QUERY = 0,
+ MEMBARRIER_CMD_SHARED = (1 << 0),
+ /* reserved for MEMBARRIER_CMD_SHARED_EXPEDITED (1 << 1) */
+ /* reserved for MEMBARRIER_CMD_PRIVATE (1 << 2) */
+ MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
+ MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
};
#ifdef RCU_MEMBARRIER
static int init_done;
+static int urcu_memb_has_sys_membarrier_private_expedited;
+
#ifndef CONFIG_RCU_FORCE_SYS_MEMBARRIER
-int rcu_has_sys_membarrier_memb;
+/*
+ * Explicitly initialize to zero because we can't alias a non-static
+ * uninitialized variable.
+ */
+int urcu_memb_has_sys_membarrier = 0;
#endif
void __attribute__((constructor)) rcu_init(void);
void __attribute__((constructor)) rcu_init(void);
void __attribute__((destructor)) rcu_exit(void);
+
+static DEFINE_URCU_TLS(int, rcu_signal_was_blocked);
#endif
/*
* rcu_registry_lock may nest inside rcu_gp_lock.
*/
static pthread_mutex_t rcu_registry_lock = PTHREAD_MUTEX_INITIALIZER;
-struct rcu_gp rcu_gp = { .ctr = RCU_GP_COUNT };
+struct urcu_gp rcu_gp = { .ctr = URCU_GP_COUNT };
/*
* Written to only by each individual reader. Read by both the reader and the
* writers.
*/
-DEFINE_URCU_TLS_IE(struct rcu_reader, rcu_reader);
+DEFINE_URCU_TLS(struct urcu_reader, rcu_reader);
static CDS_LIST_HEAD(registry);
#ifdef RCU_MEMBARRIER
static void smp_mb_master(void)
{
- if (caa_likely(rcu_has_sys_membarrier_memb))
- (void) membarrier(MEMBARRIER_CMD_SHARED, 0);
- else
+ if (caa_likely(urcu_memb_has_sys_membarrier)) {
+ if (membarrier(urcu_memb_has_sys_membarrier_private_expedited ?
+ MEMBARRIER_CMD_PRIVATE_EXPEDITED :
+ MEMBARRIER_CMD_SHARED, 0))
+ urcu_die(errno);
+ } else {
cmm_smp_mb();
+ }
}
#endif
#ifdef RCU_SIGNAL
static void force_mb_all_readers(void)
{
- struct rcu_reader *index;
+ struct urcu_reader *index;
/*
* Ask for each threads to execute a cmm_smp_mb() so we can consider the
smp_mb_master();
/* Temporarily unlock the registry lock. */
mutex_unlock(&rcu_registry_lock);
- if (uatomic_read(&rcu_gp.futex) != -1)
- goto end;
- while (futex_async(&rcu_gp.futex, FUTEX_WAIT, -1,
- NULL, NULL, 0)) {
+ while (uatomic_read(&rcu_gp.futex) == -1) {
+ if (!futex_async(&rcu_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. */
goto end;
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);
struct cds_list_head *qsreaders)
{
unsigned int wait_loops = 0;
- struct rcu_reader *index, *tmp;
+ struct urcu_reader *index, *tmp;
#ifdef HAS_INCOHERENT_CACHES
unsigned int wait_gp_loops = 0;
#endif /* HAS_INCOHERENT_CACHES */
}
cds_list_for_each_entry_safe(index, tmp, input_readers, node) {
- switch (rcu_reader_state(&index->ctr)) {
- case RCU_READER_ACTIVE_CURRENT:
+ switch (urcu_common_reader_state(&rcu_gp, &index->ctr)) {
+ case URCU_READER_ACTIVE_CURRENT:
if (cur_snap_readers) {
cds_list_move(&index->node,
cur_snap_readers);
break;
}
/* Fall-through */
- case RCU_READER_INACTIVE:
+ case URCU_READER_INACTIVE:
cds_list_move(&index->node, qsreaders);
break;
- case RCU_READER_ACTIVE_OLD:
+ case URCU_READER_ACTIVE_OLD:
/*
* Old snapshot. Leaving node in
* input_readers will make us busy-loop
/*
* 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);
cmm_smp_mb();
/* Switch parity: 0 -> 1, 1 -> 0 */
- CMM_STORE_SHARED(rcu_gp.ctr, rcu_gp.ctr ^ RCU_GP_CTR_PHASE);
+ CMM_STORE_SHARED(rcu_gp.ctr, rcu_gp.ctr ^ URCU_GP_CTR_PHASE);
/*
* Must commit rcu_gp.ctr update to memory before waiting for quiescent
/*
* 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);
return _rcu_read_ongoing();
}
+#ifdef RCU_SIGNAL
+/*
+ * Make sure the signal used by the urcu-signal flavor is unblocked
+ * while the thread is registered.
+ */
+static
+void urcu_signal_unblock(void)
+{
+ sigset_t mask, oldmask;
+ int ret;
+
+ ret = sigemptyset(&mask);
+ urcu_posix_assert(!ret);
+ ret = sigaddset(&mask, SIGRCU);
+ urcu_posix_assert(!ret);
+ ret = pthread_sigmask(SIG_UNBLOCK, &mask, &oldmask);
+ urcu_posix_assert(!ret);
+ URCU_TLS(rcu_signal_was_blocked) = sigismember(&oldmask, SIGRCU);
+}
+
+static
+void urcu_signal_restore(void)
+{
+ sigset_t mask;
+ int ret;
+
+ if (!URCU_TLS(rcu_signal_was_blocked))
+ return;
+ ret = sigemptyset(&mask);
+ urcu_posix_assert(!ret);
+ ret = sigaddset(&mask, SIGRCU);
+ urcu_posix_assert(!ret);
+ ret = pthread_sigmask(SIG_BLOCK, &mask, NULL);
+ urcu_posix_assert(!ret);
+}
+#else
+static
+void urcu_signal_unblock(void) { }
+static
+void urcu_signal_restore(void) { }
+#endif
+
void rcu_register_thread(void)
{
+ urcu_signal_unblock();
+
URCU_TLS(rcu_reader).tid = pthread_self();
- assert(URCU_TLS(rcu_reader).need_mb == 0);
- assert(!(URCU_TLS(rcu_reader).ctr & RCU_GP_CTR_NEST_MASK));
+ urcu_posix_assert(URCU_TLS(rcu_reader).need_mb == 0);
+ urcu_posix_assert(!(URCU_TLS(rcu_reader).ctr & URCU_GP_CTR_NEST_MASK));
mutex_lock(&rcu_registry_lock);
- assert(!URCU_TLS(rcu_reader).registered);
+ urcu_posix_assert(!URCU_TLS(rcu_reader).registered);
URCU_TLS(rcu_reader).registered = 1;
rcu_init(); /* In case gcc does not support constructor attribute */
cds_list_add(&URCU_TLS(rcu_reader).node, ®istry);
void rcu_unregister_thread(void)
{
mutex_lock(&rcu_registry_lock);
- assert(URCU_TLS(rcu_reader).registered);
+ urcu_posix_assert(URCU_TLS(rcu_reader).registered);
URCU_TLS(rcu_reader).registered = 0;
cds_list_del(&URCU_TLS(rcu_reader).node);
mutex_unlock(&rcu_registry_lock);
+
+ urcu_signal_restore();
}
#ifdef RCU_MEMBARRIER
#ifdef CONFIG_RCU_FORCE_SYS_MEMBARRIER
static
-void rcu_sys_membarrier_status(int available)
+void rcu_sys_membarrier_status(bool available)
{
if (!available)
abort();
}
#else
static
-void rcu_sys_membarrier_status(int available)
+void rcu_sys_membarrier_status(bool available)
{
- if (available)
- rcu_has_sys_membarrier_memb = 1;
+ if (!available)
+ return;
+ urcu_memb_has_sys_membarrier = 1;
}
#endif
-void rcu_init(void)
+static
+void rcu_sys_membarrier_init(void)
{
- int ret;
+ bool available = false;
+ int mask;
+
+ mask = membarrier(MEMBARRIER_CMD_QUERY, 0);
+ if (mask >= 0) {
+ if (mask & MEMBARRIER_CMD_PRIVATE_EXPEDITED) {
+ if (membarrier(MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED, 0))
+ urcu_die(errno);
+ urcu_memb_has_sys_membarrier_private_expedited = 1;
+ available = true;
+ } else if (mask & MEMBARRIER_CMD_SHARED) {
+ available = true;
+ }
+ }
+ rcu_sys_membarrier_status(available);
+}
+void rcu_init(void)
+{
if (init_done)
return;
init_done = 1;
- ret = membarrier(MEMBARRIER_CMD_QUERY, 0);
- rcu_sys_membarrier_status(ret >= 0 && (ret & MEMBARRIER_CMD_SHARED));
+ rcu_sys_membarrier_init();
}
#endif
#ifdef RCU_SIGNAL
-static void sigrcu_handler(int signo, siginfo_t *siginfo, void *context)
+static void sigrcu_handler(int signo __attribute__((unused)),
+ siginfo_t *siginfo __attribute__((unused)),
+ void *context __attribute__((unused)))
{
/*
* Executing this cmm_smp_mb() is the only purpose of this signal handler.
* application exits.
* 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));
*/
}