mempool: add unlikely and likely hints

Add unlikely and likely hints to the function mempool_free.  It lays out
the code in such a way that the common path is executed straighforward and
saves a cache line.

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Mikulas Patocka 2014-04-07 15:37:35 -07:00 • committed by Linus Torvalds
commit eb9a3c62a0

View file

@ -304,9 +304,9 @@ void mempool_free(void *element, mempool_t *pool)
* ensures that there will be frees which return elements to the
* pool waking up the waiters.
*/
if (pool->curr_nr < pool->min_nr) {
if (unlikely(pool->curr_nr < pool->min_nr)) {
spin_lock_irqsave(&pool->lock, flags);
if (pool->curr_nr < pool->min_nr) {
if (likely(pool->curr_nr < pool->min_nr)) {
add_element(pool, element);
spin_unlock_irqrestore(&pool->lock, flags);
wake_up(&pool->wait);