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authorShaohua Li <shaohua.li@intel.com>2011-11-14 13:34:13 +0800
committerPekka Enberg <penberg@kernel.org>2011-11-15 20:41:00 +0200
commit9ada19342b2441f290f0043ed7c562682c8c4ede (patch)
tree702599b3b616d4bce7415012d8d4d18c7c43e5ec /mm/slub.c
parentf64ae042d94d376b54e7a343d93c48561e9d2e16 (diff)
slub: move discard_slab out of node lock
Lockdep reports there is potential deadlock for slub node list_lock. discard_slab() is called with the lock hold in unfreeze_partials(), which could trigger a slab allocation, which could hold the lock again. discard_slab() doesn't need hold the lock actually, if the slab is already removed from partial list. Acked-by: Christoph Lameter <cl@linux.com> Reported-and-tested-by: Yong Zhang <yong.zhang0@gmail.com> Reported-and-tested-by: Julie Sullivan <kernelmail.jms@gmail.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c16
1 files changed, 12 insertions, 4 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 60e16c43f88..00efbb56a26 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1862,7 +1862,7 @@ static void unfreeze_partials(struct kmem_cache *s)
{
struct kmem_cache_node *n = NULL;
struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
- struct page *page;
+ struct page *page, *discard_page = NULL;
while ((page = c->partial)) {
enum slab_modes { M_PARTIAL, M_FREE };
@@ -1916,14 +1916,22 @@ static void unfreeze_partials(struct kmem_cache *s)
"unfreezing slab"));
if (m == M_FREE) {
- stat(s, DEACTIVATE_EMPTY);
- discard_slab(s, page);
- stat(s, FREE_SLAB);
+ page->next = discard_page;
+ discard_page = page;
}
}
if (n)
spin_unlock(&n->list_lock);
+
+ while (discard_page) {
+ page = discard_page;
+ discard_page = discard_page->next;
+
+ stat(s, DEACTIVATE_EMPTY);
+ discard_slab(s, page);
+ stat(s, FREE_SLAB);
+ }
}
/*