X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;ds=sidebyside;f=urcu%2Fstatic%2Furcu-qsbr.h;h=68bfc31f540ee07adbb0701251adac9ccb0434b5;hb=a0b7f7ea3fc3339a1c42caffd53ce9f056e5b901;hp=5b7adac658bfe1b64264d3adcf2b06e0a00c2430;hpb=408f6d9220576478e5ce9a20256d579fc9bfa954;p=urcu.git

diff --git a/urcu/static/urcu-qsbr.h b/urcu/static/urcu-qsbr.h
index 5b7adac..68bfc31 100644
--- a/urcu/static/urcu-qsbr.h
+++ b/urcu/static/urcu-qsbr.h
@@ -124,6 +124,7 @@ struct rcu_reader {
 	unsigned long ctr;
 	/* Data used for registry */
 	struct cds_list_head node __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
+	int waiting;
 	pthread_t tid;
 };
 
@@ -136,7 +137,11 @@ extern int32_t gp_futex;
  */
 static inline void wake_up_gp(void)
 {
-	if (unlikely(uatomic_read(&gp_futex) == -1)) {
+	if (caa_unlikely(_CMM_LOAD_SHARED(rcu_reader.waiting))) {
+		_CMM_STORE_SHARED(rcu_reader.waiting, 0);
+		cmm_smp_mb();
+		if (uatomic_read(&gp_futex) != -1)
+			return;
 		uatomic_set(&gp_futex, 0);
 		futex_noasync(&gp_futex, FUTEX_WAKE, 1,
 		      NULL, NULL, 0);