linux-kernel - Re: [PATCH 1/1] RFC: add pidfd_send_signal flag to reclaim mm while killing a process

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Message-ID: <20201118154334.GT12284@dhcp22.suse.cz>
Date:   Wed, 18 Nov 2020 20:10:21 +0100
From:   Michal Hocko <mhocko@...e.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Suren Baghdasaryan <surenb@...gle.com>,
        David Rientjes <rientjes@...gle.com>,
        Matthew Wilcox <willy@...radead.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Roman Gushchin <guro@...com>, Rik van Riel <riel@...riel.com>,
        Christian Brauner <christian@...uner.io>,
        Oleg Nesterov <oleg@...hat.com>,
        Tim Murray <timmurray@...gle.com>, linux-api@...r.kernel.org,
        linux-mm <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-team <kernel-team@...roid.com>,
        Minchan Kim <minchan@...nel.org>
Subject: Re: [PATCH 1/1] RFC: add pidfd_send_signal flag to reclaim mm while
 killing a process

On Fri 13-11-20 18:16:32, Andrew Morton wrote:
[...]
> It's all sounding a bit painful (but not *too* painful).  But to
> reiterate, I do think that adding the ability for a process to shoot
> down a large amount of another process's memory is a lot more generally
> useful than tying it to SIGKILL, agree?

I am not sure TBH. Is there any reasonable usecase where uncoordinated
memory tear down is OK and a target process which is able to see the
unmapped memory?
-- 
Michal Hocko
SUSE Labs