From: Jens Axboe <[email protected]>
To: Jeffle Xu <[email protected]>
Cc: [email protected], [email protected],
[email protected]
Subject: Re: [PATCH] block: fix potential IO hang when turning off io_poll
Date: Mon, 22 Feb 2021 06:40:22 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 2/21/21 11:54 PM, Jeffle Xu wrote:
> QUEUE_FLAG_POLL flag will be cleared when turning off 'io_poll', while
> at that moment there may be IOs stuck in hw queue uncompleted. The
> following polling routine won't help reap these IOs, since blk_poll()
> will return immediately because of cleared QUEUE_FLAG_POLL flag. Thus
> these IOs will hang until they finnaly time out. The hang out can be
> observed by 'fio --engine=io_uring iodepth=1', while turning off
> 'io_poll' at the same time.
>
> To fix this, freeze and flush the request queue first when turning off
> 'io_poll'.
Applied, thanks. Fixed up the braces.
--
Jens Axboe
prev parent reply other threads:[~2021-02-22 13:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-22 6:54 [PATCH] block: fix potential IO hang when turning off io_poll Jeffle Xu
2021-02-22 7:12 ` Joseph Qi
2021-02-22 7:46 ` JeffleXu
2021-02-22 13:40 ` Jens Axboe [this message]
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