Re: [PATCH RESEND] slub: fix a memory leak in get_partial_node()
From: Pekka Enberg
Date: Fri May 18 2012 - 05:25:29 EST
On Thu, 17 May 2012, Joonsoo Kim wrote:
> 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.
>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Acked-by: Christoph Lameter <cl@xxxxxxxxx>
> Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>
Applied, thanks!
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