linux-kernel - Re: [PATCH 0/3] locking/mutex: Add mutex_timed_lock() to solve potential deadlock problems

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Message-ID: <a8f67483-5ae1-98b6-a1f8-5985e5a8f889@redhat.com>
Date:   Tue, 11 Feb 2020 18:31:06 -0500
From:   Waiman Long <longman@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Christoph Lameter <cl@...ux.com>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 0/3] locking/mutex: Add mutex_timed_lock() to solve
 potential deadlock problems

On 2/11/20 7:31 AM, Peter Zijlstra wrote:
> On Mon, Feb 10, 2020 at 03:46:48PM -0500, Waiman Long wrote:
>> An alternative solution proposed by this patchset is to add a new
>> mutex_timed_lock() call that allows an additional timeout argument. This
>> function will return an error code if timeout happens. The use of this
>> new API will prevent deadlock from happening while allowing the task
>> to wait a sufficient period of time before giving up.
> We've always rejected timed_lock implementation because, as akpm has
> already expressed, their need is disgusting.
>
That is fine. I will see if the lock order can be changed in a way to
address the problem.

Thanks,
Longman