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From: Michal Hocko <mhocko@kernel.org>
To: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Multiple oom_reaper BUGs: unmap_page_range racing with exit_mmap
Date: Fri, 8 Dec 2017 08:50:14 +0100	[thread overview]
Message-ID: <20171208075014.GN20234@dhcp22.suse.cz> (raw)
In-Reply-To: <alpine.DEB.2.10.1712071315570.135101@chino.kir.corp.google.com>

On Thu 07-12-17 13:22:30, David Rientjes wrote:
[...]
> > diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
> > index 9c8847395b5e..da673ca66e7a 100644
> > --- a/include/linux/sched/coredump.h
> > +++ b/include/linux/sched/coredump.h
> > @@ -68,8 +68,9 @@ static inline int get_dumpable(struct mm_struct *mm)
> >  #define MMF_RECALC_UPROBES	20	/* MMF_HAS_UPROBES can be wrong */
> >  #define MMF_OOM_SKIP		21	/* mm is of no interest for the OOM killer */
> >  #define MMF_UNSTABLE		22	/* mm is unstable for copy_from_user */
> > -#define MMF_HUGE_ZERO_PAGE	23      /* mm has ever used the global huge zero page */
> > -#define MMF_DISABLE_THP		24	/* disable THP for all VMAs */
> > +#define MMF_OOM_VICTIM		23	/* mm is the oom victim */
> > +#define MMF_HUGE_ZERO_PAGE	24      /* mm has ever used the global huge zero page */
> > +#define MMF_DISABLE_THP		25	/* disable THP for all VMAs */
> >  #define MMF_DISABLE_THP_MASK	(1 << MMF_DISABLE_THP)
> >  
> >  #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
> 
> Could we not adjust the bit values, but simply add new one for 
> MMF_OOM_VICTIM?  We have automated tools that look at specific bits in 
> mm->flags and it would be nice to not have them be inconsistent between 
> kernel versions.  Not absolutely required, but nice to avoid.

I just wanted to have those semantically related bits closer
together. But I do not insist on this.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2017-12-08  7:50 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-06  2:43 Multiple oom_reaper BUGs: unmap_page_range racing with exit_mmap David Rientjes
2017-12-06  2:58 ` David Rientjes
     [not found]   ` <201712060328.vB63SrDK069830@www262.sakura.ne.jp>
2017-12-06  7:48     ` David Rientjes
2017-12-06  9:00       ` Michal Hocko
     [not found]         ` <201712070720.vB77KlBQ009754@www262.sakura.ne.jp>
2017-12-07  8:28           ` Michal Hocko
2017-12-07  8:44             ` Michal Hocko
2017-12-07 11:00             ` Tetsuo Handa
2017-12-07 21:22             ` David Rientjes
2017-12-08  7:50               ` Michal Hocko [this message]
2017-12-06 11:37       ` Tetsuo Handa
2017-12-06  8:50     ` Michal Hocko
2017-12-06  8:31 ` Michal Hocko
2017-12-07 11:35 ` Michal Hocko
2017-12-07 15:44   ` Tetsuo Handa
2017-12-07 16:30     ` Michal Hocko
2017-12-07 21:55       ` David Rientjes
2017-12-08  9:26         ` David Rientjes
2017-12-08 11:27           ` Michal Hocko
2017-12-08 10:11       ` Tetsuo Handa

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