RCU: use SEQ_CST MO

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/src/rcu.h b/src/rcu.h
index ab2e4c82b401bac8b24b845725c5ba3f2f72acd3..be01cb7dd31dedd1205fdc511898ef10cea49307 100644 (file)
--- a/src/rcu.h
+++ b/src/rcu.h
@@ -86,7 +86,7 @@ void wait_for_cpus(struct side_rcu_gp_state *gp_state)
                 * a thread migration during the traversal over each
                 * cpu.
                 */
-               __atomic_thread_fence(__ATOMIC_ACQ_REL);
+               __atomic_thread_fence(__ATOMIC_SEQ_CST);
 
                for (i = 0; i < gp_state->nr_cpus; i++) {
                        struct side_rcu_cpu_gp_state *cpu_state = &gp_state->percpu_state[i];
@@ -106,25 +106,25 @@ static inline
 void side_rcu_wait_grace_period(struct side_rcu_gp_state *gp_state)
 {
        /*
-        * This release fence pairs with the acquire MO __atomic_add_fetch
-        * in side_rcu_read_begin().
+        * This fence pairs with the acquire MO __atomic_add_fetch in
+        * side_rcu_read_begin().
         */
-       __atomic_thread_fence(__ATOMIC_RELEASE);
+       __atomic_thread_fence(__ATOMIC_SEQ_CST);
 
        pthread_mutex_lock(&gp_state->gp_lock);
 
        wait_for_cpus(gp_state);
 
        /* Flip period: 0 -> 1, 1 -> 0. */
-       (void) __atomic_xor_fetch(&gp_state->period, 1, __ATOMIC_RELAXED);
+       (void) __atomic_xor_fetch(&gp_state->period, 1, __ATOMIC_SEQ_CST);
 
        wait_for_cpus(gp_state);
 
        pthread_mutex_unlock(&gp_state->gp_lock);
 
        /*
-        * This acquire fence pairs with the release MO __atomic_add_fetch
-        * in side_rcu_read_end().
+        * This fence pairs with the release MO __atomic_add_fetch in
+        * side_rcu_read_end().
         */
-       __atomic_thread_fence(__ATOMIC_ACQUIRE);
+       __atomic_thread_fence(__ATOMIC_SEQ_CST);
 }