From: Michal Hocko <mhocko@kernel.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@techsingularity.net>,
Vlastimil Babka <vbabka@suse.cz>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Sangseok Lee <sangseok.lee@lge.com>
Subject: Re: [PATCH 3/4] mm: unreserve highatomic free pages fully before OOM
Date: Tue, 11 Oct 2016 10:01:08 +0200 [thread overview]
Message-ID: <20161011080108.GE31996@dhcp22.suse.cz> (raw)
In-Reply-To: <20161011073716.GA22314@bbox>
On Tue 11-10-16 16:37:16, Minchan Kim wrote:
> On Tue, Oct 11, 2016 at 09:26:06AM +0200, Michal Hocko wrote:
> > On Tue 11-10-16 16:09:45, Minchan Kim wrote:
[...]
> > > @@ -2154,12 +2156,24 @@ static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
> > > * may increase.
> > > */
> > > set_pageblock_migratetype(page, ac->migratetype);
> > > - move_freepages_block(zone, page, ac->migratetype);
> > > - spin_unlock_irqrestore(&zone->lock, flags);
> > > - return;
> > > + ret = move_freepages_block(zone, page,
> > > + ac->migratetype);
> > > + /*
> > > + * By race with page freeing functions, !highatomic
> > > + * pageblocks can have free pages in highatomic free
> > > + * list so if drain is true, try to unreserve every
> > > + * free pages in highatomic free list without bailing
> > > + * out.
> > > + */
> > > + if (!drain) {
> >
> > if (ret)
> > > + spin_unlock_irqrestore(&zone->lock, flags);
> > > + return ret;
> > > + }
> >
> > arguably this would work better also for !drain case which currently
> > tries to unreserve but in case of the race it would do nothing.
>
> I thought it but I was afraid if you say again it's over complicated.
Well, maybe there is even better/easier solution. Anyway, if
I were you I would just split it into two patches. The first
to unreserve from shoudl_reclaim_retry and the later to make
unreserve_highatomic_pageblock more reliable.
> I will do it with your SOB in next spin.
ok, thanks!
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-10-11 8:01 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 5:45 [PATCH 0/4] use up highorder free pages before OOM Minchan Kim
2016-10-07 5:45 ` [PATCH 1/4] mm: adjust reserved highatomic count Minchan Kim
2016-10-07 12:30 ` Vlastimil Babka
2016-10-07 14:29 ` Minchan Kim
2016-10-10 6:57 ` Vlastimil Babka
2016-10-11 4:19 ` Minchan Kim
2016-10-11 9:40 ` Vlastimil Babka
2016-10-12 5:36 ` Mel Gorman
2016-10-07 5:45 ` [PATCH 2/4] mm: prevent double decrease of nr_reserved_highatomic Minchan Kim
2016-10-07 12:44 ` Vlastimil Babka
2016-10-07 14:30 ` Minchan Kim
2016-10-12 5:36 ` Mel Gorman
2016-10-07 5:45 ` [PATCH 3/4] mm: unreserve highatomic free pages fully before OOM Minchan Kim
2016-10-07 9:09 ` Michal Hocko
2016-10-07 14:43 ` Minchan Kim
2016-10-10 7:41 ` Michal Hocko
2016-10-11 5:01 ` Minchan Kim
2016-10-11 6:50 ` Michal Hocko
2016-10-11 7:09 ` Minchan Kim
2016-10-11 7:26 ` Michal Hocko
2016-10-11 7:37 ` Minchan Kim
2016-10-11 8:01 ` Michal Hocko [this message]
2016-10-07 5:45 ` [PATCH 4/4] mm: skip to reserve pageblock crossed zone boundary for HIGHATOMIC Minchan Kim
2016-10-07 9:16 ` [PATCH 0/4] use up highorder free pages before OOM Michal Hocko
2016-10-07 15:04 ` Minchan Kim
2016-10-10 7:47 ` Michal Hocko
2016-10-11 5:06 ` Minchan Kim
2016-10-11 6:53 ` Michal Hocko
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