Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 20 Nov 2018 10:05:20 -0800
From:   Tejun Heo <tj@kernel.org>
To:     Roman Gushchin <guro@fb.com>
Cc:     Roman Gushchin <guroan@gmail.com>, Oleg Nesterov <oleg@redhat.com>,
        "cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH v3 4/7] cgroup: cgroup v2 freezer
Message-ID: <20181120180520.GZ2509588@devbig004.ftw2.facebook.com>
References: <20181117003830.15344-1-guro@fb.com>
 <20181117003830.15344-5-guro@fb.com>
 <20181120162529.GU2509588@devbig004.ftw2.facebook.com>
 <20181120163304.GA21462@tower.DHCP.thefacebook.com>
 <20181120163604.GX2509588@devbig004.ftw2.facebook.com>
 <20181120164349.GB21462@tower.DHCP.thefacebook.com>
 <20181120164859.GY2509588@devbig004.ftw2.facebook.com>
 <20181120173858.GC21462@tower.DHCP.thefacebook.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20181120173858.GC21462@tower.DHCP.thefacebook.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hello,

On Tue, Nov 20, 2018 at 05:39:03PM +0000, Roman Gushchin wrote:
> Yeah, it's a good point. I've thought about it mostly in the fork() context,
> where if freezing of a cgroup races with fork(), it makes no sense to
> switch the cgroup state back and forth. But that case is different, as
> the child will be trapped just on the return path from fork() call.

I think it'd be best to tie the task counter transitions to cgroup
state update and propagation so that the state is always reflective of
the task states.

Thanks.

-- 
tejun