From: Jens Axboe <axboe@kernel.dk>
To: Baolin Wang <baolin.wang@linux.alibaba.com>, tj@kernel.org
Cc: joseph.qi@linux.alibaba.com, linux-block@vger.kernel.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] blk-cgroup: Use cond_resched() when destroy blkgs
Date: Thu, 28 Jan 2021 07:32:03 -0700 [thread overview]
Message-ID: <9087d02b-ef9b-46c4-6933-82bb3e520597@kernel.dk> (raw)
In-Reply-To: <0be1a0a03367f7230497a2e7a5ed47d2a2d5ae1a.1611809091.git.baolin.wang@linux.alibaba.com>
On 1/27/21 10:58 PM, 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
Thanks, applied.
--
Jens Axboe
prev parent reply other threads:[~2021-01-28 14:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 5:58 [PATCH v3] blk-cgroup: Use cond_resched() when destroy blkgs Baolin Wang
2021-01-28 14:32 ` Jens Axboe [this message]
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