unsigned int max = n;
int success;
+ *old_head = __atomic_load_n(&r->prod.head, __ATOMIC_RELAXED);
do {
/* Reset n to the initial burst count */
n = max;
- *old_head = __atomic_load_n(&r->prod.head,
- __ATOMIC_ACQUIRE);
+ /* Ensure the head is read before tail */
+ __atomic_thread_fence(__ATOMIC_ACQUIRE);
/* load-acquire synchronize with store-release of ht->tail
* in update_tail.
if (is_sp)
r->prod.head = *new_head, success = 1;
else
+ /* on failure, *old_head is updated */
success = __atomic_compare_exchange_n(&r->prod.head,
old_head, *new_head,
- 0, __ATOMIC_ACQUIRE,
+ 0, __ATOMIC_RELAXED,
__ATOMIC_RELAXED);
} while (unlikely(success == 0));
return n;
int success;
/* move cons.head atomically */
+ *old_head = __atomic_load_n(&r->cons.head, __ATOMIC_RELAXED);
do {
/* Restore n as it may change every loop */
n = max;
- *old_head = __atomic_load_n(&r->cons.head,
- __ATOMIC_ACQUIRE);
+ /* Ensure the head is read before tail */
+ __atomic_thread_fence(__ATOMIC_ACQUIRE);
/* this load-acquire synchronize with store-release of ht->tail
* in update_tail.
if (is_sc)
r->cons.head = *new_head, success = 1;
else
+ /* on failure, *old_head will be updated */
success = __atomic_compare_exchange_n(&r->cons.head,
old_head, *new_head,
- 0, __ATOMIC_ACQUIRE,
+ 0, __ATOMIC_RELAXED,
__ATOMIC_RELAXED);
} while (unlikely(success == 0));
return n;