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authorChristoph Lameter <cl@linux.com>2014-10-10 02:26:11 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-10 06:25:51 +0400
commitc9e16131d6e39bddd183f0b9d787ec0a62bf0eeb (patch)
treed0a92993d7077e883459e49c3971bde51116bcb7 /mm/slub.c
parent25c4f304be8cd6831105d3a2876028e4ecd254a1 (diff)
downloadlinux-c9e16131d6e39bddd183f0b9d787ec0a62bf0eeb.tar.xz
slub: disable tracing and failslab for merged slabs
Tracing of mergeable slabs as well as uses of failslab are confusing since the objects of multiple slab caches will be affected. Moreover this creates a situation where a mergeable slab will become unmergeable. If tracing or failslab testing is desired then it may be best to switch merging off for starters. Signed-off-by: Christoph Lameter <cl@linux.com> Tested-by: WANG Chao <chaowang@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 3e8afcc07a76..fa86e5845093 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4604,6 +4604,14 @@ static ssize_t trace_show(struct kmem_cache *s, char *buf)
static ssize_t trace_store(struct kmem_cache *s, const char *buf,
size_t length)
{
+ /*
+ * Tracing a merged cache is going to give confusing results
+ * as well as cause other issues like converting a mergeable
+ * cache into an umergeable one.
+ */
+ if (s->refcount > 1)
+ return -EINVAL;
+
s->flags &= ~SLAB_TRACE;
if (buf[0] == '1') {
s->flags &= ~__CMPXCHG_DOUBLE;
@@ -4721,6 +4729,9 @@ static ssize_t failslab_show(struct kmem_cache *s, char *buf)
static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
size_t length)
{
+ if (s->refcount > 1)
+ return -EINVAL;
+
s->flags &= ~SLAB_FAILSLAB;
if (buf[0] == '1')
s->flags |= SLAB_FAILSLAB;