linux-kernel - Re: [PATCH 1/4] sched: move IO scheduling accounting from io_schedule_timeout() to _

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Date:   Tue, 6 Dec 2016 16:30:32 -0500
From:   Tejun Heo <tj@...nel.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Tejun Heo <htejun@...com>, torvalds@...ux-foundation.org,
        akpm@...ux-foundation.org, mingo@...hat.com, axboe@...nel.dk,
        tytso@....edu, jack@...e.com, adilger.kernel@...ger.ca,
        linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-team@...com, mingbo@...com
Subject: Re: [PATCH 1/4] sched: move IO scheduling accounting from
 io_schedule_timeout() to __schedule()

Hello,

On Mon, Oct 31, 2016 at 10:45:56AM -0600, Tejun Heo wrote:
> Tracking the owners of mutexes and rwsems does help quite a bit.  I
> don't think it's as simple as inheriting io sleep state from the
> current owner tho.  The owner might be running or in a non-IO sleep
> when others try to grab the mutex.  It is an option to ignore those
> cases but this would have a real possibility to lead to surprising
> results in some corner cases.  If we choose to propagate dynamically,
> it becomes an a lot more complex problem and I don't think it'd be
> justfiable.
> 
> Unless there can be a simple enough and reliable solution, I think
> it'd be better to stick with explicit marking.

Just posted the fixed version for the first patch.  Any more thoughts
on this?

Thanks.

-- 
tejun