linux-kernel - Re: [PATCH] oom: Make coredump interruptible

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Message-ID: <20100604113425.GA13801@redhat.com>
Date:	Fri, 4 Jun 2010 13:34:25 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	Roland McGrath <roland@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	David Rientjes <rientjes@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Nick Piggin <npiggin@...e.de>
Subject: Re: [PATCH] oom: Make coredump interruptible

On 06/04, Oleg Nesterov wrote:
>
> (I'd suggest you to add a note into the changelog, to explain
>  that the new flag makes sense even without coredump problems).

And. May I ask you to add another note into the changelog?

> > @@ -410,6 +409,8 @@ static int __oom_kill_process(struct task_struct *p, struct mem_cgroup *mem,
> >  	 */
> >  	p->rt.time_slice = HZ;
> >  	set_tsk_thread_flag(p, TIF_MEMDIE);
> > +	set_bit(MMF_OOM_KILLED, &p->mm->flags);

I think the changelog should explain that, if we race with fork(),
this flag can't leak into the child's new mm. mm_init() filters
the bits outside of MMF_INIT_MASK.

If we race with exec, it can't leak because mm_alloc() does
memset(0).

Oleg.

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