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Message-ID: <41fdf6cb-ec1b-ff07-44f4-3ba01b45ebda@huawei.com>
Date: Wed, 15 May 2024 10:47:07 +0800
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Subject: Re: [PATCH -next] memcg: don't handle event_list for v2 when
 offlining
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To: Roman Gushchin <roman.gushchin@linux.dev>, Michal Hocko <mhocko@suse.com>
CC: <hannes@cmpxchg.org>, <shakeel.butt@linux.dev>, <muchun.song@linux.dev>,
	<akpm@linux-foundation.org>, <cgroups@vger.kernel.org>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>
References: <20240514131106.1326323-1-xiujianfeng@huawei.com>
 <ZkNwthw5vJrnQSLL@tiehlicka> <ZkOBaNffNi4rmR8h@P9FQF9L96D>
From: xiujianfeng <xiujianfeng@huawei.com>
In-Reply-To: <ZkOBaNffNi4rmR8h@P9FQF9L96D>
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On 2024/5/14 23:21, Roman Gushchin wrote:
> On Tue, May 14, 2024 at 04:09:58PM +0200, Michal Hocko wrote:
>> On Tue 14-05-24 13:11:06, Xiu Jianfeng wrote:
>>> The event_list for memcg is only valid for v1 and not used for v2,
>>> so it's unnessesary to handle event_list for v2.
>>
>> You are right but the code as is works just fine. The list will be
>> empty. It is true that we do not need to take event_list_lock lock but
>> nobody should be using this lock anyway. Also the offline callback is
>> not particularly hot path. So why do we want to change the code?
> 
> +1 to that.
> 
> Plus this code will be moved to a separate function in mm/memcontrol-v1.c
> and luckily can be compiled out entirely for users who don't need the
> cgroup v1 support.

I found the patchset you mentioned, Thanks.

> 
> Thanks!