path: root/mm
diff options
authorShaohua Li <>2011-08-23 08:36:59 +0800
committerPekka Enberg <>2011-08-27 11:58:59 +0300
commit130655ef097940b627e8e04fa7c6f3b51cf24f85 (patch)
treec5b968196fe7f7ffcbe9def5dc70dc413a318dbd /mm
parent81107188f123e3c2217ac2f2feb2a1147904c62f (diff)
slub: add slab with one free object to partial list tail
The slab has just one free object, adding it to partial list head doesn't make sense. And it can cause lock contentation. For example, 1. CPU takes the slab from partial list 2. fetch an object 3. switch to another slab 4. free an object, then the slab is added to partial list again In this way n->list_lock will be heavily contended. In fact, Alex had a hackbench regression. 3.1-rc1 performance drops about 70% against 3.0. This patch fixes it. Acked-by: Christoph Lameter <> Reported-by: Alex Shi <> Signed-off-by: Shaohua Li <> Signed-off-by: Shaohua Li <> Signed-off-by: Pekka Enberg <>
Diffstat (limited to 'mm')
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 9f662d70eb47..7c54fe83a90c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2377,7 +2377,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
if (unlikely(!prior)) {
remove_full(s, page);
- add_partial(n, page, 0);
+ add_partial(n, page, 1);