From: Zhang Yanfei <zhangyanfei.ok@hotmail.com>
To: Vlastimil Babka <vbabka@suse.cz>, Joonsoo Kim <js1304@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: 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>
Subject: Re: [PATCH v2 2/4] mm/compaction: stop the isolation when we isolate enough freepage
Date: Sat, 31 Jan 2015 18:17:55 +0800 [thread overview]
Message-ID: <BLU436-SMTP107979843453A8D45167B5D833E0@phx.gbl> (raw)
In-Reply-To: <54CC92FD.5000601@suse.cz>
At 2015/1/31 16:31, Vlastimil Babka wrote:
> On 01/31/2015 08:49 AM, Zhang Yanfei wrote:
>> Hello,
>>
>> At 2015/1/30 20:34, Joonsoo Kim wrote:
>>
>> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
>>
>> IMHO, the patch making the free scanner move slower makes both scanners
>> meet further. Before this patch, if we isolate too many free pages and even
>> after we release the unneeded free pages later the free scanner still already
>> be there and will be moved forward again next time -- the free scanner just
>> cannot be moved back to grab the free pages we released before no matter where
>> the free pages in, pcp or buddy.
>
> It can be actually moved back. If we are releasing free pages, it means the
> current compaction is terminating, and it will set zone->compact_cached_free_pfn
> back to the position of the released free page that was furthest back. The next
> compaction will start from the cached free pfn.
Yeah, you are right. I missed the release_freepages(). Thanks!
>
> It is however possible that another compaction runs in parallel and has
> progressed further and overwrites the cached free pfn.
>
Hmm, maybe.
Thanks.
next prev parent reply other threads:[~2015-01-31 10:18 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
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 [this message]
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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