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From: David Sterba <dsterba@suse.cz>
To: Xianting Tian <tian.xianting@h3c.com>
Cc: clm@fb.com, josef@toxicpanda.com, dsterba@suse.com,
	linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] btrfs: prevent hung check firing during long sync IO
Date: Wed, 19 Aug 2020 15:28:31 +0200	[thread overview]
Message-ID: <20200819132831.GL2026@twin.jikos.cz> (raw)
In-Reply-To: <20200819101451.24266-1-tian.xianting@h3c.com>

On Wed, Aug 19, 2020 at 06:14:51PM +0800, Xianting Tian wrote:
> For sync and flush io, it may take long time to complete.
> So it's better to use wait_for_completion_io_timeout() in a
> while loop to avoid prevent hung check and crash(when set
> /proc/sys/kernel/hung_task_panic).

I wonder if long running IO should trigger the panic/kill of the task at
all. A warning means that the system is under load but as long as it's
making some progress it should be ok, and that seems to be a separate
case from a task that's not making any progress (and terminating it is
probably the best option).

> This is similar to prevent hung task check in submit_bio_wait(),
> blk_execute_rq().

I see, adding that workaround to btrfs would be 3rd occurence and this
should go into a wrapper, eg. wait_for_completion_io_nowarn with
examples where this should be used.

      reply	other threads:[~2020-08-19 13:29 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-19 10:14 [PATCH] btrfs: prevent hung check firing during long sync IO Xianting Tian
2020-08-19 13:28 ` David Sterba [this message]

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