From: Jens Axboe <axboe@kernel.dk>
To: Hugh Dickins <hughd@google.com>
Cc: Keith Busch <kbusch@kernel.org>,
linux-block@vger.kernel.org, Liu Song <liusong@linux.alibaba.com>,
Hillf Danton <hdanton@sina.com>, Jan Kara <jack@suse.cz>,
linux-kernel@vger.kernel.org, Yu Kuai <yukuai1@huaweicloud.com>
Subject: Re: [PATCH next v3] sbitmap: fix lockup while swapping
Date: Thu, 29 Sep 2022 17:58:41 -0600 [thread overview]
Message-ID: <166449592135.4485.5114483552637281957.b4-ty@kernel.dk> (raw)
In-Reply-To: <9c2038a7-cdc5-5ee-854c-fbc6168bf16@google.com>
On Thu, 29 Sep 2022 12:50:12 -0700 (PDT), Hugh Dickins wrote:
> Commit 4acb83417cad ("sbitmap: fix batched wait_cnt accounting")
> is a big improvement: without it, I had to revert to before commit
> 040b83fcecfb ("sbitmap: fix possible io hung due to lost wakeup")
> to avoid the high system time and freezes which that had introduced.
>
> Now okay on the NVME laptop, but 4acb83417cad is a disaster for heavy
> swapping (kernel builds in low memory) on another: soon locking up in
> sbitmap_queue_wake_up() (into which __sbq_wake_up() is inlined), cycling
> around with waitqueue_active() but wait_cnt 0 . Here is a backtrace,
> showing the common pattern of outer sbitmap_queue_wake_up() interrupted
> before setting wait_cnt 0 back to wake_batch (in some cases other CPUs
> are idle, in other cases they're spinning for a lock in dd_bio_merge()):
>
> [...]
Applied, thanks!
[1/1] sbitmap: fix lockup while swapping
commit: 30514bd2dd4e86a3ecfd6a93a3eadf7b9ea164a0
Best regards,
--
Jens Axboe
next prev parent reply other threads:[~2022-09-29 23:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-18 21:10 [PATCH next] sbitmap: fix lockup while swapping Hugh Dickins
2022-09-19 21:22 ` Keith Busch
2022-09-19 23:01 ` Hugh Dickins
2022-09-21 16:40 ` Jan Kara
2022-09-23 14:43 ` Jan Kara
2022-09-23 15:13 ` Keith Busch
2022-09-23 16:16 ` Hugh Dickins
2022-09-23 19:07 ` Keith Busch
2022-09-23 21:29 ` Hugh Dickins
2022-09-23 23:15 ` Hugh Dickins
2022-09-26 11:44 ` Jan Kara
2022-09-26 14:08 ` Yu Kuai
2022-09-27 3:39 ` Hugh Dickins
2022-09-27 10:31 ` Jan Kara
2022-09-28 3:56 ` Hugh Dickins
2022-09-28 3:59 ` [PATCH next v2] " Hugh Dickins
2022-09-28 4:07 ` Hugh Dickins
2022-09-29 8:39 ` Jan Kara
2022-09-29 19:50 ` [PATCH next v3] " Hugh Dickins
2022-09-29 19:56 ` Keith Busch
2022-09-29 23:58 ` Jens Axboe [this message]
[not found] ` <20220924023047.1410-1-hdanton@sina.com>
2022-09-27 4:02 ` [PATCH next] " Hugh Dickins
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