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Subject: Re: [PATCH block/for-next] blk-cgroup: cgroup_rstat_updated()
 shouldn't be called on cgroup1
To:     Tejun Heo <tj@kernel.org>
Cc:     Faiz Abbas <faiz_abbas@ti.com>, cgroups@vger.kernel.org,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        lizefan@huawei.com, hannes@cmpxchg.org, kernel-team@fb.com,
        Dan Schatzberg <dschatzberg@fb.com>, Daniel Xu <dlxu@fb.com>
References: <20191107191804.3735303-1-tj@kernel.org>
 <20191107191804.3735303-6-tj@kernel.org>
 <cd3ebcee-6819-a09b-aeba-de6817f32cde@ti.com>
 <20191113163501.GI4163745@devbig004.ftw2.facebook.com>
 <20191114223128.GM4163745@devbig004.ftw2.facebook.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <091022e8-e6a1-178d-80cd-b2a070d3519f@kernel.dk>
Date:   Mon, 18 Nov 2019 08:41:14 -0700
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On 11/14/19 3:31 PM, Tejun Heo wrote:
> Currently, cgroup rstat is supported only on cgroup2 hierarchy and
> rstat functions shouldn't be called on cgroup1 cgroups.  While
> converting blk-cgroup core statistics to rstat, f73316482977
> ("blk-cgroup: reimplement basic IO stats using cgroup rstat")
> accidentally ended up calling cgroup_rstat_updated() on cgroup1
> cgroups causing crashes.
> 
> Longer term, we probably should add cgroup1 support to rstat but for
> now let's mask the call directly.

Applied, thanks.

-- 
Jens Axboe