From: Andrea Arcangeli <aarcange@redhat.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: akpm@linux-foundation.org, Ury Stankevich <urykhy@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
stable@kernel.org
Subject: Re: [PATCH] mm: compaction: Abort compaction if too many pages are isolated and caller is asynchronous
Date: Mon, 30 May 2011 16:31:09 +0200 [thread overview]
Message-ID: <20110530143109.GH19505@random.random> (raw)
In-Reply-To: <20110530131300.GQ5044@csn.ul.ie>
Hi Mel and everyone,
On Mon, May 30, 2011 at 02:13:00PM +0100, Mel Gorman wrote:
> Asynchronous compaction is used when promoting to huge pages. This is
> all very nice but if there are a number of processes in compacting
> memory, a large number of pages can be isolated. An "asynchronous"
> process can stall for long periods of time as a result with a user
> reporting that firefox can stall for 10s of seconds. This patch aborts
> asynchronous compaction if too many pages are isolated as it's better to
> fail a hugepage promotion than stall a process.
>
> If accepted, this should also be considered for 2.6.39-stable. It should
> also be considered for 2.6.38-stable but ideally [11bc82d6: mm:
> compaction: Use async migration for __GFP_NO_KSWAPD and enforce no
> writeback] would be applied to 2.6.38 before consideration.
Is this supposed to fix the stall with khugepaged in D state and other
processes in D state?
zoneinfo showed a nr_isolated_file = -1, I don't think that meant
compaction had 4g pages isolated really considering it moves from
-1,0, 1. So I'm unsure if this fix could be right if the problem is
the hang with khugepaged in D state reported, so far that looked more
like a bug with PREEMPT in the vmstat accounting of nr_isolated_file
that trips in too_many_isolated of both vmscan.c and compaction.c with
PREEMPT=y. Or are you fixing a different problem?
Or how do you explain this -1 value out of nr_isolated_file? Clearly
when that value goes to -1, compaction.c:too_many_isolated will hang,
I think we should fix the -1 value before worrying about the rest...
grep nr_isolated_file zoneinfo-khugepaged
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
nr_isolated_file 1
nr_isolated_file 4294967295
nr_isolated_file 0
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next prev parent reply other threads:[~2011-05-30 14:31 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-30 13:13 Mel Gorman
2011-05-30 14:31 ` Andrea Arcangeli [this message]
2011-05-30 15:37 ` Mel Gorman
2011-05-30 16:55 ` Mel Gorman
2011-05-30 17:53 ` Andrea Arcangeli
2011-05-31 12:16 ` Minchan Kim
2011-05-31 12:24 ` Andrea Arcangeli
2011-05-31 13:33 ` Minchan Kim
2011-05-31 14:14 ` Andrea Arcangeli
2011-05-31 14:37 ` Minchan Kim
2011-05-31 14:38 ` Minchan Kim
2011-06-02 18:23 ` Andrea Arcangeli
2011-06-02 20:21 ` Minchan Kim
2011-06-02 20:59 ` Minchan Kim
2011-06-02 22:03 ` Andrea Arcangeli
2011-06-02 21:40 ` Andrea Arcangeli
2011-06-02 22:23 ` Minchan Kim
2011-06-02 22:32 ` Andrea Arcangeli
2011-06-02 23:01 ` Minchan Kim
2011-06-03 17:37 ` Andrea Arcangeli
2011-06-03 18:07 ` Andrea Arcangeli
2011-06-04 7:59 ` Minchan Kim
2011-06-06 10:32 ` Mel Gorman
2011-06-06 12:49 ` Andrea Arcangeli
2011-06-06 14:47 ` Mel Gorman
2011-06-06 14:07 ` Minchan Kim
2011-06-06 10:15 ` Mel Gorman
2011-06-06 10:26 ` Mel Gorman
2011-06-06 14:01 ` Minchan Kim
2011-06-06 14:26 ` Minchan Kim
2011-06-02 23:02 ` Minchan Kim
2011-06-01 0:57 ` Mel Gorman
2011-06-01 9:24 ` Mel Gorman
2011-06-01 17:58 ` Mel Gorman
2011-06-01 19:15 ` Andrea Arcangeli
2011-06-01 21:40 ` Mel Gorman
2011-06-01 23:30 ` Andrea Arcangeli
2011-06-02 1:03 ` Mel Gorman
2011-06-02 8:34 ` Minchan Kim
2011-06-02 13:29 ` Andrea Arcangeli
2011-06-02 14:50 ` Mel Gorman
2011-06-02 15:37 ` Andrea Arcangeli
2011-06-03 2:09 ` Mel Gorman
2011-06-03 14:49 ` Mel Gorman
2011-06-03 15:45 ` Andrea Arcangeli
2011-06-04 7:25 ` Minchan Kim
2011-06-06 10:39 ` Mel Gorman
2011-06-06 12:38 ` Andrea Arcangeli
2011-06-06 14:55 ` Mel Gorman
2011-06-06 14:19 ` Minchan Kim
2011-06-06 22:32 ` Andrew Morton
2011-06-04 6:58 ` Minchan Kim
2011-06-06 10:43 ` Mel Gorman
2011-06-06 12:40 ` Andrea Arcangeli
2011-06-06 13:27 ` Minchan Kim
2011-06-06 13:23 ` Minchan Kim
2011-05-31 14:34 ` Mel Gorman
2011-05-30 14:45 ` [stable] " Greg KH
2011-05-30 16:14 ` Minchan Kim
2011-05-31 8:32 ` Mel Gorman
2011-05-31 4:48 ` KAMEZAWA Hiroyuki
2011-05-31 5:38 ` Minchan Kim
2011-05-31 7:14 ` KOSAKI Motohiro
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