The patch titled
slab: Fix kmem_cache_destroy() on NUMA
has been added to the -mm tree. Its filename is
slab-fix-kmem_cache_destroy-on-numa.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
From: Roland Dreier <rdreier@xxxxxxxxx>
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@xxxxxxxxxxxx>.
Cc: Christoph Lameter <clameter@xxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Signed-off-by: Roland Dreier <rolandd@xxxxxxxxx>
Cc: Eric Dumazet <dada1@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/slab.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)
diff -puN mm/slab.c~slab-fix-kmem_cache_destroy-on-numa mm/slab.c
--- 25/mm/slab.c~slab-fix-kmem_cache_destroy-on-numa Mon May 15 13:14:57 2006
+++ 25-akpm/mm/slab.c Mon May 15 13:14:57 2006
@@ -2200,11 +2200,14 @@ static void drain_cpu_caches(struct kmem
check_irq_on();
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);
- }
}
}
_
Patches currently in -mm which might be from rdreier@xxxxxxxxx are
slab-fix-kmem_cache_destroy-on-numa.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
