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From: Zefan Li <lizefan@huawei.com>
To: bsingharora@gmail.com
Cc: cgroups@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [RFC][PATCH] cgroup_threadgroup_rwsem - affects scalability and OOM
Date: Wed, 10 Aug 2016 09:31:42 +0800	[thread overview]
Message-ID: <57AA83FE.1050809@huawei.com> (raw)
In-Reply-To: <20160809135703.GA11823@350D>

>> For example, I'm trying to fix a race. See https://lkml.org/lkml/2016/8/8/900
>>
>> And the fix kind of relies on the fact that cgroup_post_fork() is placed
>> inside the read section of cgroup_threadgroup_rwsem, so that cpuset_fork()
>> won't race with cgroup migration.
>>
> 
> My patch retains that behaviour, before ss->fork() is called we hold
> the cgroup_threadgroup_rwsem, in fact it is held prior to ss->can_fork()
> 

I read the patch again and now I see only threadgroup_change_begin() is moved
downwards, and threadgroup_change_end() remains intact. Then I have no problem
with it.

Acked-by: Zefan Li <lizefan@huawei.com>

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  reply	other threads:[~2016-08-10  1:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-09  4:19 [RFC][PATCH] cgroup_threadgroup_rwsem - affects scalability and OOM Balbir Singh
2016-08-09  6:29 ` Tejun Heo
2016-08-09  7:02   ` Balbir Singh
2016-08-09 14:26     ` Tejun Heo
2016-08-10  1:21       ` Balbir Singh
2016-08-09  9:00 ` Zefan Li
2016-08-09 13:57   ` Balbir Singh
2016-08-10  1:31     ` Zefan Li [this message]
2016-08-09 18:09 ` Oleg Nesterov
2016-08-10 19:43 ` Tejun Heo
2016-08-11 23:47   ` Balbir Singh

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