path: root/mm/mempool.c
diff options
authorTejun Heo <>2012-01-10 15:08:28 -0800
committerLinus Torvalds <>2012-01-10 16:30:45 -0800
commit1ebb7044c9142c67d1d2b04d84010b4810a43fd8 (patch)
treebfacd21f2aabf0b727d678797e2764d010918f29 /mm/mempool.c
parent0565d317768cc66b13e37184f29d9f270c2886dc (diff)
mempool: fix first round failure behavior
mempool modifies gfp_mask so that the backing allocator doesn't try too hard or trigger warning message when there's pool to fall back on. In addition, for the first try, it removes __GFP_WAIT and IO, so that it doesn't trigger reclaim or wait when allocation can be fulfilled from pool; however, when that allocation fails and pool is empty too, it waits for the pool to be replenished before retrying. Allocation which could have succeeded after a bit of reclaim has to wait on the reserved items and it's not like mempool doesn't retry with __GFP_WAIT and IO. It just does that *after* someone returns an element, pointlessly delaying things. Fix it by retrying immediately if the first round of allocation attempts w/o __GFP_WAIT and IO fails. [ shorten the lock hold time] Signed-off-by: Tejun Heo <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm/mempool.c')
1 files changed, 11 insertions, 2 deletions
diff --git a/mm/mempool.c b/mm/mempool.c
index e3a802a0cea0..d9049811f352 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -221,14 +221,23 @@ repeat_alloc:
return element;
- /* We must not sleep in the GFP_ATOMIC case */
+ /*
+ * We use gfp mask w/o __GFP_WAIT or IO for the first round. If
+ * alloc failed with that and @pool was empty, retry immediately.
+ */
+ if (gfp_temp != gfp_mask) {
+ spin_unlock_irqrestore(&pool->lock, flags);
+ gfp_temp = gfp_mask;
+ goto repeat_alloc;
+ }
+ /* We must not sleep if !__GFP_WAIT */
if (!(gfp_mask & __GFP_WAIT)) {
spin_unlock_irqrestore(&pool->lock, flags);
return NULL;
/* Let's wait for someone else to return an element to @pool */
- gfp_temp = gfp_mask;
prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);