From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Changhui Zhong <czhong@redhat.com>
Subject: Re: [PATCH] block: avoid io timeout in case of sync polled dio
Date: Wed, 13 Apr 2022 09:51:13 -0700 [thread overview]
Message-ID: <Ylb/gciNitj7yd/c@infradead.org> (raw)
In-Reply-To: <20220413084805.1571884-1-ming.lei@redhat.com>
On Wed, Apr 13, 2022 at 04:48:05PM +0800, Ming Lei wrote:
> If the bio is marked as POLLED after submission,
Umm, a bio should never be marked POLLED after submission.
> bio_poll() should be
> called for reaping io since there isn't irq for completing the request,
> so we can't call into blk_io_schedule() in case that bio_poll() returns
> zero.
>
> Also for calling bio_poll(), current->plug has to be flushed out,
> otherwise bio may not be issued to driver, and ->bi_cookie won't
> be set.
I think we just need to bypass the plug to start with for synchronous
polled I/O.
Do you have a reproducer? We'd also need to sort all this out for
polled file system I/O as well.
next prev parent reply other threads:[~2022-04-13 16:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-13 8:48 [PATCH] block: avoid io timeout in case of sync polled dio Ming Lei
2022-04-13 16:51 ` Christoph Hellwig [this message]
2022-04-14 1:38 ` Ming Lei
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