From: Tejun Heo <tj@kernel.org>
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: axboe@kernel.dk, joseph.qi@linux.alibaba.com,
linux-block@vger.kernel.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] blk-cgroup: Use cond_resched() when destroy blkgs
Date: Wed, 27 Jan 2021 22:31:05 -0500 [thread overview]
Message-ID: <YBIv+fG6jleTxOTh@slm.duckdns.org> (raw)
In-Reply-To: <8e8a0c4644d5eb01b7f79ec9b67c2b240f4a6434.1611798287.git.baolin.wang@linux.alibaba.com>
On Thu, Jan 28, 2021 at 11:22:00AM +0800, Baolin Wang wrote:
> On !PREEMPT kernel, we can get below softlockup when doing stress
> testing with creating and destroying block cgroup repeatly. The
> reason is it may take a long time to acquire the queue's lock in
> the loop of blkcg_destroy_blkgs(), or the system can accumulate a
> huge number of blkgs in pathological cases. We can add a need_resched()
> check on each loop and release locks and do cond_resched() if true
> to avoid this issue, since the blkcg_destroy_blkgs() is not called
> from atomic contexts.
>
> [ 4757.010308] watchdog: BUG: soft lockup - CPU#11 stuck for 94s!
> [ 4757.010698] Call trace:
> [ 4757.010700] blkcg_destroy_blkgs+0x68/0x150
> [ 4757.010701] cgwb_release_workfn+0x104/0x158
> [ 4757.010702] process_one_work+0x1bc/0x3f0
> [ 4757.010704] worker_thread+0x164/0x468
> [ 4757.010705] kthread+0x108/0x138
>
> Suggested-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Thanks.
--
tejun
next prev parent reply other threads:[~2021-01-28 3:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 3:22 [PATCH v2] blk-cgroup: Use cond_resched() when destroy blkgs Baolin Wang
2021-01-28 3:31 ` Tejun Heo [this message]
2021-01-28 3:41 ` Jens Axboe
2021-01-28 3:49 ` Baolin Wang
2021-01-28 3:51 ` Jens Axboe
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