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| author | Joonsoo Kim <js1304@gmail.com> | 2012-05-17 00:13:02 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-10 00:36:11 +0900 |
| commit | 75df3ae2060eb00b909ac65fc4d2798c4e53969a (patch) | |
| tree | 1a4fa75c42c7d182e4ab6595d3850de491cf0d0c /mm | |
| parent | 22aca500eb55daf5c84bffb001d3cce14da08b08 (diff) | |
slub: fix a memory leak in get_partial_node()
commit 02d7633fa567be7bf55a993b79d2a31b95ce2227 upstream.
In the case which is below,
1. acquire slab for cpu partial list
2. free object to it by remote cpu
3. page->freelist = t
then memory leak is occurred.
Change acquire_slab() not to zap freelist when it works for cpu partial list.
I think it is a sufficient solution for fixing a memory leak.
Below is output of 'slabinfo -r kmalloc-256'
when './perf stat -r 30 hackbench 50 process 4000 > /dev/null' is done.
***Vanilla***
Sizes (bytes) Slabs Debug Memory
------------------------------------------------------------------------
Object : 256 Total : 468 Sanity Checks : Off Total: 3833856
SlabObj: 256 Full : 111 Redzoning : Off Used : 2004992
SlabSiz: 8192 Partial: 302 Poisoning : Off Loss : 1828864
Loss : 0 CpuSlab: 55 Tracking : Off Lalig: 0
Align : 8 Objects: 32 Tracing : Off Lpadd: 0
***Patched***
Sizes (bytes) Slabs Debug Memory
------------------------------------------------------------------------
Object : 256 Total : 300 Sanity Checks : Off Total: 2457600
SlabObj: 256 Full : 204 Redzoning : Off Used : 2348800
SlabSiz: 8192 Partial: 33 Poisoning : Off Loss : 108800
Loss : 0 CpuSlab: 63 Tracking : Off Lalig: 0
Align : 8 Objects: 32 Tracing : Off Lpadd: 0
Total and loss number is the impact of this patch.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slub.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/slub.c b/mm/slub.c index 80848cd3901c..71de9b5685fa 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1514,15 +1514,19 @@ static inline void *acquire_slab(struct kmem_cache *s, freelist = page->freelist; counters = page->counters; new.counters = counters; - if (mode) + if (mode) { new.inuse = page->objects; + new.freelist = NULL; + } else { + new.freelist = freelist; + } VM_BUG_ON(new.frozen); new.frozen = 1; } while (!__cmpxchg_double_slab(s, page, freelist, counters, - NULL, new.counters, + new.freelist, new.counters, "lock and freeze")); remove_partial(n, page); @@ -1564,7 +1568,6 @@ static void *get_partial_node(struct kmem_cache *s, object = t; available = page->objects - page->inuse; } else { - page->freelist = t; available = put_cpu_partial(s, page, 0); stat(s, CPU_PARTIAL_NODE); } |