From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
torvalds@linux-foundation.org, rientjes@google.com
Subject: Re: [PATCH 0/8] OOM killer/reaper changes for avoiding OOM lockup problem.
Date: Tue, 10 Jul 2018 12:57:57 +0900 [thread overview]
Message-ID: <201807100357.w6A3vv5o062894@www262.sakura.ne.jp> (raw)
In-Reply-To: <20180706055644.GG32658@dhcp22.suse.cz>
> On Fri 06-07-18 11:40:07, Tetsuo Handa wrote:
> > > > > > Of course, we don't have to remove the OOM reaper kernel thread.
> > > > >
> > > > > The thing is that the current design uses the oom_reaper only as a
> > > > > backup to get situation unstuck. Once you move all that heavy lifting
> > > > > into the oom path directly then you will have to handle all sorts of
> > > > > issues. E.g. how do you handle that a random process hitting OOM path
> > > > > has to pay the full price to tear down multi TB process? This is a lot
> > > > > of time.
> > > >
> > > > We can add a threshold to unmap_page_range() (for direct OOM reaping threads)
> > > > which aborts after given number of pages are reclaimed. There is no need to
> > > > reclaim all pages at once if the caller is doing memory allocations.
> > >
> > > Yes, there is no need to reclaim all pages. OOM is after freeing _some_
> > > memory after all. But that means further complications down the unmap
> > > path. I do not really see any reason for that.
> >
> > "I do not see reason for that" cannot become a reason direct OOM reaping has to
> > reclaim all pages at once.
>
> We are not going to polute deep mm guts for unlikely events like oom.
>
As far as I tested, below approach does not pollute deep mm guts. It should
achieve what David wants to do, without introducing user-visible tunable
interface.
David, can you try these patches?
prev parent reply other threads:[~2018-07-10 3:58 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-03 14:25 [PATCH 0/8] OOM killer/reaper changes for avoiding OOM lockup problem Tetsuo Handa
2018-07-03 14:25 ` [PATCH 1/8] mm,oom: Don't call schedule_timeout_killable() with oom_lock held Tetsuo Handa
2018-07-03 14:38 ` Michal Hocko
2018-07-03 14:25 ` [PATCH 2/8] mm,oom: Check pending victims earlier in out_of_memory() Tetsuo Handa
2018-07-03 14:25 ` [PATCH 3/8] mm,oom: Fix unnecessary killing of additional processes Tetsuo Handa
2018-07-03 14:58 ` Michal Hocko
2018-07-03 14:25 ` [PATCH 4/8] mm,page_alloc: Make oom_reserves_allowed() even Tetsuo Handa
2018-07-03 14:25 ` [PATCH 5/8] mm,oom: Bring OOM notifier to outside of oom_lock Tetsuo Handa
2018-07-03 14:59 ` Michal Hocko
2018-07-03 14:25 ` [PATCH 6/8] mm,oom: Make oom_lock static variable Tetsuo Handa
2018-07-03 14:25 ` [PATCH 7/8] mm,oom: Do not sleep with oom_lock held Tetsuo Handa
2018-07-03 14:25 ` [PATCH 8/8] mm,page_alloc: Move the short sleep to should_reclaim_retry() Tetsuo Handa
2018-07-03 15:12 ` [PATCH 0/8] OOM killer/reaper changes for avoiding OOM lockup problem Michal Hocko
2018-07-03 15:29 ` Michal Hocko
2018-07-04 2:22 ` penguin-kernel
2018-07-04 7:16 ` Michal Hocko
2018-07-04 7:22 ` Michal Hocko
2018-07-05 3:05 ` Tetsuo Handa
2018-07-05 7:24 ` Michal Hocko
2018-07-06 2:40 ` Tetsuo Handa
2018-07-06 2:49 ` Linus Torvalds
2018-07-07 1:12 ` Tetsuo Handa
2018-07-09 7:45 ` Michal Hocko
2018-07-06 5:56 ` Michal Hocko
2018-07-10 3:57 ` Tetsuo Handa [this message]
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