Date: Thu, 8 Nov 2012 15:47:00 +0100
From: Michal Hocko <mhocko@suse.cz>
To: Tejun Heo <tj@kernel.org>
Cc: lizefan@huawei.com, rjw@sisk.pl, containers@lists.linux-foundation.org,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, fweisbec@gmail.com
Subject: Re: [PATCH 6/9] cgroup_freezer: make freezer->state mask of flags
Message-ID: <20121108144700.GK31821@dhcp22.suse.cz>
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On Thu 08-11-12 06:39:52, Tejun Heo wrote:
> Hello, Michal.
> 
> On Thu, Nov 08, 2012 at 11:39:28AM +0100, Michal Hocko wrote:
> > On Sat 03-11-12 01:38:32, Tejun Heo wrote:
> > > freezer->state was an enum value - one of THAWED, FREEZING and FROZEN.
> > > As the scheduled full hierarchy support requires more than one
> > > freezing condition, switch it to mask of flags.  If FREEZING is not
> > > set, it's thawed.  FREEZING is set if freezing or frozen.  If frozen,
> > > both FREEZING and FROZEN are set.  Now that tasks can be attached to
> > > an already frozen cgroup, this also makes freezing condition checks
> > > more natural.
> > > 
> > > This patch doesn't introduce any behavior change.
> > > 
> > > Signed-off-by: Tejun Heo <tj@kernel.org>
> > 
> > I think it would be nicer to use freezer_state_flags enum rather than
> > unsigned int for the state. I would even expect gcc to complain about
> > that but it looks like -fstrict-enums is c++ specific (so long enum
> > safety).
> 
> But if you use it as flag bits, the resulting value no longer is
> inside the defined enum values.  Isn't that weird?

Ahh, there is always CGROUP_FREEZER_ONLINE which would overcomplicate
the possible and valid masks.
Please ignore this...

-- 
Michal Hocko
SUSE Labs
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