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Date:   Mon, 27 Apr 2020 13:13:04 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Yang Yingliang <yangyingliang@huawei.com>
Cc:     tj@kernel.org, lizefan@huawei.com, cgroups@vger.kernel.org,
        linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com,
        linux-mm@kvack.org, guro@cmpxchg.org
Subject: Re: memleak in cgroup
Message-ID: <20200427171304.GC29022@cmpxchg.org>
References: <6e4d5208-ba26-93ed-c600-4776fc620456@huawei.com>
 <34dfdb52-6efd-7b11-07c8-9461a13b3aa4@huawei.com>
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+cc Roman who has been looking the most at this area

On Mon, Apr 27, 2020 at 03:48:13PM +0800, Yang Yingliang wrote:
> +cc linux-mm@kvack.org <mailto:linux-mm@kvack.org>
> 
> On 2020/4/26 19:21, Yang Yingliang wrote:
> > Hi,
> > 
> > When I doing the follow test in kernel-5.7-rc2, I found mem-free is
> > decreased
> > 
> > #!/bin/sh
> > cd /sys/fs/cgroup/memory/
> > 
> > for((i=0;i<45;i++))
> > do
> > ??????? for((j=0;j<60000;j++))
> > ??????? do
> > ??????????????? mkdir /sys/fs/cgroup/memory/yyl-cg$j
> > ??????? done
> > ??????? sleep 1
> > ??????? ls /sys/fs/cgroup/memory/ | grep yyl | xargs rmdir
> > done

Should be easy enough to reproduce, thanks for the report. I'll try to
take a look later this week, unless Roman beats me to it.

Is this a new observation in 5.7-rc2?

Can you provide /sys/fs/cgroup/unified/cgroup.stat after the test?