From: Zefan Li <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
To: bsingharora-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org"
<linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.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-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
WARNING: multiple messages have this Message-ID (diff)
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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next prev parent reply other threads:[~2016-08-10 1:31 UTC|newest]
Thread overview: 19+ 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 4:19 ` Balbir Singh
[not found] ` <4717ef90-ca86-4a34-c63a-94b8b4bfaaec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-08-09 6:29 ` Tejun Heo
2016-08-09 6:29 ` Tejun Heo
2016-08-09 7:02 ` Balbir Singh
[not found] ` <0a7ffe43-c0c6-85df-9bc2-d00fc837e284-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-08-09 14:26 ` Tejun Heo
2016-08-09 14:26 ` Tejun Heo
[not found] ` <20160809142603.GE4906-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2016-08-10 1:21 ` Balbir Singh
2016-08-10 1:21 ` Balbir Singh
2016-08-09 9:00 ` Zefan Li
2016-08-09 9:00 ` Zefan Li
2016-08-09 13:57 ` Balbir Singh
2016-08-10 1:31 ` Zefan Li [this message]
2016-08-10 1:31 ` Zefan Li
2016-08-09 18:09 ` Oleg Nesterov
2016-08-10 19:43 ` Tejun Heo
2016-08-10 19:43 ` Tejun Heo
[not found] ` <20160810194306.GP25053-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2016-08-11 23:47 ` Balbir Singh
2016-08-11 23:47 ` Balbir Singh
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