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From: Mel Gorman <mgorman@suse.de>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Hugh Dickins <hughd@google.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Yong-Taek Lee <ytk.lee@samsung.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH v2] mm/page_alloc: fix freeing of MIGRATE_RESERVE migratetype pages
Date: Thu, 13 Mar 2014 14:25:40 +0000	[thread overview]
Message-ID: <20140313142540.GQ10663@suse.de> (raw)
In-Reply-To: <42197912.c6v2hLDCey@amdc1032>

On Fri, Feb 14, 2014 at 07:34:17PM +0100, Bartlomiej Zolnierkiewicz wrote:
> Pages allocated from MIGRATE_RESERVE migratetype pageblocks
> are not freed back to MIGRATE_RESERVE migratetype free
> lists in free_pcppages_bulk()->__free_one_page() if we got
> to free_pcppages_bulk() through drain_[zone_]pages().
> The freeing through free_hot_cold_page() is okay because
> freepage migratetype is set to pageblock migratetype before
> calling free_pcppages_bulk().  If pages of MIGRATE_RESERVE
> migratetype end up on the free lists of other migratetype
> whole Reserved pageblock may be later changed to the other
> migratetype in __rmqueue_fallback() and it will be never
> changed back to be a Reserved pageblock.  Fix the issue by
> preserving freepage migratetype as a pageblock migratetype
> (instead of overriding it to the requested migratetype)
> for MIGRATE_RESERVE migratetype pages in rmqueue_bulk().
> 
> The problem was introduced in v2.6.31 by commit ed0ae21
> ("page allocator: do not call get_pageblock_migratetype()
> more than necessary").
> 
> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Reported-by: Yong-Taek Lee <ytk.lee@samsung.com>
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Hugh Dickins <hughd@google.com>

It's a pity about the unconditional pageblock lookup in that path but I
didn't see a better way around it so

Acked-by: Mel Gorman <mgorman@suse.de>

-- 
Mel Gorman
SUSE Labs

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  parent reply	other threads:[~2014-03-13 14:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-14 18:34 [RFC][PATCH v2] mm/page_alloc: fix freeing of MIGRATE_RESERVE migratetype pages Bartlomiej Zolnierkiewicz
2014-02-24  8:59 ` Mel Gorman
2014-03-06 18:12   ` Bartlomiej Zolnierkiewicz
2014-03-13 14:25 ` Mel Gorman [this message]
2014-03-13 14:37   ` Bartlomiej Zolnierkiewicz
2014-03-13 15:05     ` Mel Gorman

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