From: Linus Torvalds <torvalds@linux-foundation.org>
To: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Tejun Heo <tj@kernel.org>, Marc MERLIN <marc@merlins.org>,
Jens Axboe <axboe@fb.com>, Michal Hocko <mhocko@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>, linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: 4.8.8 kernel trigger OOM killer repeatedly when I have lots of RAM that should be free
Date: Thu, 1 Dec 2016 10:16:41 -0800 [thread overview]
Message-ID: <CA+55aFxrwATJtaAzVCnHHaHqusDZeu8=eqffTAPFyFJk5Wn78w@mail.gmail.com> (raw)
In-Reply-To: <20161201135014.jrr65ptxczplmdkn@kmo-pixel>
On Thu, Dec 1, 2016 at 5:50 AM, Kent Overstreet
<kent.overstreet@gmail.com> wrote:
>
> That said, I'm not sure how I feel about Jens's exact approach... it seems to me
> that this can really just live within the writeback code, I don't know why it
> should involve the block layer at all. plus, if I understand correctly his code
> has the effect of blocking in generic_make_request() to throttle, which means
> due to the way the writeback code is structured we'll be blocking with page
> locks held.
Yeah, I do *not* believe that throttling at the block layer is at all
the right thing to do.
I do think that the block layer needs to throttle, but it needs to be
seen as a "last resort" kind of thing, where the block layer just
needs to limit how much it will have oending. But it should be seen as
a failure mode, not as a write balancing issue.
Because the real throttling absolutely needs to happen when things are
marked dirty, because no block layer throttling will ever fix the
situation where you just have too much memory dirtied that you cannot
free because it will take a minute to write out.
So throttling at a VM level is sane. Throttling at a block layer level is not.
Linus
next prev parent reply other threads:[~2016-12-01 18:16 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20161121154336.GD19750@merlins.org>
2016-11-21 21:50 ` 4.8.8 kernel trigger OOM killer repeatedly when I have lots of RAM that should be free Vlastimil Babka
2016-11-21 21:56 ` Marc MERLIN
2016-11-21 23:03 ` [PATCH] block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg Tejun Heo
2016-11-22 15:47 ` Vlastimil Babka
2016-11-22 16:48 ` Tejun Heo
2016-11-22 22:13 ` Linus Torvalds
2016-11-23 8:50 ` Vlastimil Babka
2016-11-28 17:19 ` Tejun Heo
2016-11-29 7:25 ` Michal Hocko
2016-11-29 16:38 ` Tejun Heo
2016-11-29 16:57 ` Vlastimil Babka
2016-11-29 17:13 ` Michal Hocko
2016-11-29 17:17 ` Linus Torvalds
2016-11-29 17:28 ` Michal Hocko
2016-11-29 17:48 ` Linus Torvalds
2016-11-22 16:00 ` Jens Axboe
2016-11-22 16:06 ` 4.8.8 kernel trigger OOM killer repeatedly when I have lots of RAM that should be free Marc MERLIN
2016-11-22 16:14 ` Vlastimil Babka
2016-11-22 16:25 ` Michal Hocko
2016-11-22 16:47 ` Marc MERLIN
2016-11-22 16:38 ` Greg Kroah-Hartman
2016-11-29 16:25 ` Michal Hocko
2016-11-29 16:43 ` Patch "mm, oom: stop pre-mature high-order OOM killer invocations" has been added to the 4.8-stable tree gregkh
2016-11-29 16:43 ` 4.8.8 kernel trigger OOM killer repeatedly when I have lots of RAM that should be free Greg Kroah-Hartman
2016-11-22 19:38 ` Linus Torvalds
2016-11-23 6:34 ` Michal Hocko
2016-11-23 6:53 ` Hillf Danton
2016-11-23 7:00 ` Michal Hocko
2016-11-23 9:18 ` Vlastimil Babka
2016-11-28 7:23 ` Michal Hocko
2016-11-28 20:55 ` Marc MERLIN
2016-11-29 15:55 ` Marc MERLIN
2016-11-29 16:07 ` Michal Hocko
2016-11-29 16:34 ` Marc MERLIN
2016-11-29 17:07 ` Linus Torvalds
2016-11-29 17:40 ` Marc MERLIN
2016-11-29 18:01 ` Linus Torvalds
2016-11-30 17:47 ` Marc MERLIN
2016-11-30 18:14 ` Linus Torvalds
2016-11-30 18:21 ` Marc MERLIN
2016-11-30 18:27 ` Jens Axboe
2016-11-30 20:30 ` Tejun Heo
2016-12-01 13:50 ` Kent Overstreet
2016-12-01 18:16 ` Linus Torvalds [this message]
2016-12-01 18:30 ` Jens Axboe
2016-12-01 18:37 ` Linus Torvalds
2016-12-01 18:46 ` Jens Axboe
2016-11-29 23:01 ` Marc MERLIN
2016-11-30 13:58 ` Tetsuo Handa
2017-05-02 4:12 ` Marc MERLIN
2017-05-02 7:44 ` Michal Hocko
2017-05-02 14:15 ` Marc MERLIN
2017-05-02 10:44 ` Tetsuo Handa
2016-11-29 16:15 ` Marc MERLIN
2016-11-22 21:46 ` Simon Kirby
2016-11-28 8:06 ` Vlastimil Babka
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