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Date: Wed, 1 Aug 2018 08:37:13 -0700
From: Matthew Wilcox <willy@infradead.org>
Subject: Re: [Question] A novel case happened when using mempool allocate
 memory.
Message-ID: <20180801153713.GA4039@bombadil.infradead.org>
References: <5B61D243.9050608@huawei.com>
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Sender: owner-linux-mm@kvack.org
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To: zhong jiang <zhongjiang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>, Johannes Weiner <hannes@cmpxchg.org>, "mgorman@techsingularity.net" <mgorman@techsingularity.net>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Laura Abbott <labbott@redhat.com>, Hugh Dickins <hughd@google.com>, Oleg Nesterov <oleg@redhat.com>, Linux Memory Management List <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>

On Wed, Aug 01, 2018 at 11:31:15PM +0800, zhong jiang wrote:
> Hi,  Everyone
> 
>  I ran across the following novel case similar to memory leak in linux-4.1 stable when allocating
>  memory object by kmem_cache_alloc.   it rarely can be reproduced.
> 
> I create a specific  mempool with 24k size based on the slab.  it can not be merged with
> other kmem cache.  I  record the allocation and free usage by atomic_add/sub.    After a while,
> I watch the specific slab consume most of total memory.   After halting the code execution.
> The counter of allocation and free is equal.  Therefore,  I am sure that module have released
> all meory resource.  but the statistic of specific slab is very high but stable by checking /proc/slabinfo.

Please post the code.