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opal/lifo: add missing opal_atomic_wmb and remove unnecessary opal_atomic_rmb #771

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Merged
merged 1 commit into from
Aug 4, 2015
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opal/lifo: add missing opal_atomic_wmb and remove unnecessary opal_atomic_rmb #771

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6 changes: 4 additions & 2 deletions opal/class/opal_lifo.h
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Original file line number Diff line number Diff line change
Expand Up @@ -187,20 +187,22 @@ static inline opal_list_item_t *opal_lifo_pop_atomic (opal_lifo_t* lifo)
{
opal_list_item_t *item;
while ((item = (opal_list_item_t *) lifo->opal_lifo_head.data.item) != &lifo->opal_lifo_ghost) {
opal_atomic_rmb();

/* ensure it is safe to pop the head */
if (opal_atomic_swap_32((volatile int32_t *) &item->item_free, 1)) {
continue;
}

opal_atomic_wmb ();

/* try to swap out the head pointer */
if (opal_atomic_cmpset_ptr (&lifo->opal_lifo_head.data.item, item,
(void *) item->opal_list_next)) {
break;
}

/* NTH: don't need another atomic here */
item->item_free = 0;

/* Do some kind of pause to release the bus */
}

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