From: Zhang Yanfei <zhangyanfei.ok@hotmail.com>
To: Joonsoo Kim <js1304@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@suse.de>,
David Rientjes <rientjes@google.com>,
Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2 1/4] mm/compaction: fix wrong order check in compact_finished()
Date: Sat, 31 Jan 2015 15:38:07 +0800 [thread overview]
Message-ID: <BLU437-SMTP63C0AFB1A443C6C8688808833E0@phx.gbl> (raw)
In-Reply-To: <1422621252-29859-2-git-send-email-iamjoonsoo.kim@lge.com>
Hello,
At 2015/1/30 20:34, Joonsoo Kim wrote:
> What we want to check here is whether there is highorder freepage
> in buddy list of other migratetype in order to steal it without
> fragmentation. But, current code just checks cc->order which means
> allocation request order. So, this is wrong.
>
> Without this fix, non-movable synchronous compaction below pageblock order
> would not stopped until compaction is complete, because migratetype of most
> pageblocks are movable and high order freepage made by compaction is usually
> on movable type buddy list.
>
> There is some report related to this bug. See below link.
>
> http://www.spinics.net/lists/linux-mm/msg81666.html
>
> Although the issued system still has load spike comes from compaction,
> this makes that system completely stable and responsive according to
> his report.
>
> stress-highalloc test in mmtests with non movable order 7 allocation doesn't
> show any notable difference in allocation success rate, but, it shows more
> compaction success rate.
>
> Compaction success rate (Compaction success * 100 / Compaction stalls, %)
> 18.47 : 28.94
>
> Cc: <stable@vger.kernel.org>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
> ---
> mm/compaction.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index b68736c..4954e19 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -1173,7 +1173,7 @@ static int __compact_finished(struct zone *zone, struct compact_control *cc,
> return COMPACT_PARTIAL;
>
> /* Job done if allocation would set block type */
> - if (cc->order >= pageblock_order && area->nr_free)
> + if (order >= pageblock_order && area->nr_free)
> return COMPACT_PARTIAL;
> }
>
>
next prev parent reply other threads:[~2015-01-31 7:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-30 12:34 [PATCH v2 0/4] enhance compaction success rate Joonsoo Kim
2015-01-30 12:34 ` [PATCH v2 1/4] mm/compaction: fix wrong order check in compact_finished() Joonsoo Kim
2015-01-30 13:27 ` Vlastimil Babka
2015-01-31 7:38 ` Zhang Yanfei [this message]
2015-01-30 12:34 ` [PATCH v2 2/4] mm/compaction: stop the isolation when we isolate enough freepage Joonsoo Kim
2015-01-30 13:47 ` Vlastimil Babka
2015-01-31 7:49 ` Zhang Yanfei
2015-01-31 8:31 ` Vlastimil Babka
2015-01-31 10:17 ` Zhang Yanfei
2015-01-30 12:34 ` [PATCH v2 3/4] mm/page_alloc: separate steal decision from steal behaviour part Joonsoo Kim
2015-01-30 14:27 ` Vlastimil Babka
2015-02-02 7:02 ` Joonsoo Kim
2015-01-31 12:38 ` Zhang Yanfei
2015-02-02 7:03 ` Joonsoo Kim
2015-01-30 12:34 ` [PATCH v2 4/4] mm/compaction: enhance compaction finish condition Joonsoo Kim
2015-01-30 14:43 ` Vlastimil Babka
2015-02-02 7:11 ` Joonsoo Kim
2015-01-31 15:58 ` Zhang Yanfei
2015-02-02 7:12 ` Joonsoo Kim
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