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Date: Mon, 29 Feb 2016 19:16:24 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        Michal Hocko <mhocko@suse.com>, Petr Cermak <petrcermak@chromium.org>
Subject: Re: [PATCH] mm, proc: make clear_refs killable
Message-ID: <20160229181623.GH3615@redhat.com>
References: <1456752417-9626-8-git-send-email-mhocko@kernel.org>
 <1456768587-24893-1-git-send-email-mhocko@kernel.org>
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On 02/29, Michal Hocko wrote:
>
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -1027,11 +1027,15 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
>  		};
>
>  		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
> +			if (down_write_killable(&mm->mmap_sem)) {
> +				count = -EINTR;
> +				goto out_mm;
> +			}
> +

We do not even need to change count, userspace won't see it anyway. But I agree
it look more clean this way.

I believe the patch is fine.

Oleg.