linux-kernel - Re: [PATCH v2] mm: Allow to kill tasks doing pcpu_alloc() and waiting for pcpu_balance

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Message-ID: <20180319163940.GA519464@devbig577.frc2.facebook.com>
Date:   Mon, 19 Mar 2018 09:39:40 -0700
From:   Tejun Heo <tj@...nel.org>
To:     Kirill Tkhai <ktkhai@...tuozzo.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, cl@...ux.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm: Allow to kill tasks doing pcpu_alloc() and
 waiting for pcpu_balance_workfn()

On Mon, Mar 19, 2018 at 06:32:10PM +0300, Kirill Tkhai wrote:
> From: Kirill Tkhai <ktkhai@...tuozzo.com>
> 
> In case of memory deficit and low percpu memory pages,
> pcpu_balance_workfn() takes pcpu_alloc_mutex for a long
> time (as it makes memory allocations itself and waits
> for memory reclaim). If tasks doing pcpu_alloc() are
> choosen by OOM killer, they can't exit, because they
> are waiting for the mutex.
> 
> The patch makes pcpu_alloc() to care about killing signal
> and use mutex_lock_killable(), when it's allowed by GFP
> flags. This guarantees, a task does not miss SIGKILL
> from OOM killer.
> 
> Signed-off-by: Kirill Tkhai <ktkhai@...tuozzo.com>

Applied to percpu/for-4.16-fixes.

Thanks.

-- 
tejun