/* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
#include "urcu-qsbr.h"
+void __attribute__((destructor)) rcu_exit(void);
+
static pthread_mutex_t urcu_mutex = PTHREAD_MUTEX_INITIALIZER;
int gp_futex;
/*
* synchronize_rcu() waiting. Single thread.
*/
-static void wait_gp(struct urcu_reader *index)
+static void wait_gp(void)
{
- uatomic_dec(&gp_futex);
- smp_mb(); /* Write futex before read reader_gp */
- if (!rcu_gp_ongoing(&index->ctr)) {
- /* Read reader_gp before write futex */
- smp_mb();
- /* Callbacks are queued, don't wait. */
- uatomic_set(&gp_futex, 0);
- } else {
- /* Read reader_gp before read futex */
- smp_rmb();
- if (uatomic_read(&gp_futex) == -1)
- futex(&gp_futex, FUTEX_WAIT, -1,
- NULL, NULL, 0);
- }
+ /* Read reader_gp before read futex */
+ smp_rmb();
+ if (uatomic_read(&gp_futex) == -1)
+ futex(&gp_futex, FUTEX_WAIT, -1,
+ NULL, NULL, 0);
}
static void wait_for_quiescent_state(void)
{
- struct urcu_reader *index;
+ LIST_HEAD(qsreaders);
+ int wait_loops = 0;
+ struct urcu_reader *index, *tmp;
if (list_empty(®istry))
return;
/*
* Wait for each thread rcu_reader_qs_gp count to become 0.
*/
- list_for_each_entry(index, ®istry, head) {
- int wait_loops = 0;
+ for (;;) {
+ wait_loops++;
+ if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) {
+ uatomic_dec(&gp_futex);
+ /* Write futex before read reader_gp */
+ smp_mb();
+ }
- while (rcu_gp_ongoing(&index->ctr)) {
- if (wait_loops++ == RCU_QS_ACTIVE_ATTEMPTS) {
- wait_gp(index);
+ list_for_each_entry_safe(index, tmp, ®istry, head) {
+ if (!rcu_gp_ongoing(&index->ctr))
+ list_move(&index->head, &qsreaders);
+ }
+
+ if (list_empty(®istry)) {
+ if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) {
+ /* Read reader_gp before write futex */
+ smp_mb();
+ uatomic_set(&gp_futex, 0);
+ }
+ break;
+ } else {
+ if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS) {
+ wait_gp();
} else {
#ifndef HAS_INCOHERENT_CACHES
cpu_relax();
}
}
}
+ /* put back the reader list in the registry */
+ list_splice(&qsreaders, ®istry);
}
/*
_rcu_read_unlock();
}
-void *rcu_dereference(void *p)
-{
- return _rcu_dereference(p);
-}
-
-void *rcu_assign_pointer_sym(void **p, void *v)
-{
- wmb();
- return STORE_SHARED(p, v);
-}
-
-void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new)
-{
- wmb();
- return uatomic_cmpxchg(p, old, _new);
-}
-
-void *rcu_xchg_pointer_sym(void **p, void *v)
-{
- wmb();
- return uatomic_xchg(p, v);
-}
-
-void *rcu_publish_content_sym(void **p, void *v)
-{
- void *oldptr;
-
- oldptr = _rcu_xchg_pointer(p, v);
- synchronize_rcu();
- return oldptr;
-}
-
void rcu_quiescent_state(void)
{
_rcu_quiescent_state();
list_del(&urcu_reader.head);
internal_urcu_unlock();
}
+
+void rcu_exit(void)
+{
+ assert(list_empty(®istry));
+}