path: root/mm
diff options
authorRoland Dreier <rdreier@cisco.com>2006-05-15 11:41:00 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-05-16 07:59:32 -0700
commita4523a8b38089478f93bc053c31f678c63f5ee1b (patch)
tree96f828650d2234aac76fe39ea38b7c7250c49349 /mm
parent[PATCH] x86_64: Don't schedule on exception stack on preemptive kernels (diff)
[PATCH] slab: Fix kmem_cache_destroy() on NUMA
With CONFIG_NUMA set, kmem_cache_destroy() may fail and say "Can't free all objects." The problem is caused by sequences such as the following (suppose we are on a NUMA machine with two nodes, 0 and 1): * Allocate an object from cache on node 0. * Free the object on node 1. The object is put into node 1's alien array_cache for node 0. * Call kmem_cache_destroy(), which ultimately ends up in __cache_shrink(). * __cache_shrink() does drain_cpu_caches(), which loops through all nodes. For each node it drains the shared array_cache and then handles the alien array_cache for the other node. However this means that node 0's shared array_cache will be drained, and then node 1 will move the contents of its alien[0] array_cache into that same shared array_cache. node 0's shared array_cache is never looked at again, so the objects left there will appear to be in use when __cache_shrink() calls __node_shrink() for node 0. So __node_shrink() will return 1 and kmem_cache_destroy() will fail. This patch fixes this by having drain_cpu_caches() do drain_alien_cache() on every node before it does drain_array() on the nodes' shared array_caches. The problem was originally reported by Or Gerlitz <ogerlitz@voltaire.com>. Signed-off-by: Roland Dreier <rolandd@cisco.com> Acked-by: Christoph Lameter <clameter@sgi.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
1 files changed, 7 insertions, 4 deletions
diff --git a/mm/slab.c b/mm/slab.c
index b1d643b5238d..d31a06bfbea5 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2200,11 +2200,14 @@ static void drain_cpu_caches(struct kmem_cache *cachep)
for_each_online_node(node) {
l3 = cachep->nodelists[node];
- if (l3) {
+ if (l3 && l3->alien)
+ drain_alien_cache(cachep, l3->alien);
+ }
+ for_each_online_node(node) {
+ l3 = cachep->nodelists[node];
+ if (l3)
drain_array(cachep, l3, l3->shared, 1, node);
- if (l3->alien)
- drain_alien_cache(cachep, l3->alien);
- }