[PATCH] mempool - only init waitqueue in slow path

Here's a small patch to improve the performance of mempool_alloc by only
initializing the wait queue when we're about to wait.

Signed-off-by: Benjamin LaHaise <benjamin.c.lahaise@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/mm/mempool.c b/mm/mempool.c
index 920c8c3ab1b..9a72f7d918f 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -204,7 +204,7 @@ void * mempool_alloc(mempool_t *pool, unsigned int __nocast gfp_mask)
 {
         void *element;
         unsigned long flags;
-        DEFINE_WAIT(wait);
+        wait_queue_t wait;
         int gfp_temp;
 
         might_sleep_if(gfp_mask & __GFP_WAIT);
@@ -235,6 +235,7 @@ repeat_alloc:
 
         /* Now start performing page reclaim */
         gfp_temp = gfp_mask;
+        init_wait(&wait);
         prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
         smp_mb();
         if (!pool->curr_nr)