From: Minchan Kim <minchan@kernel.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Heesub Shin <heesub.shin@samsung.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Dongjun Shin <d.j.shin@samsung.com>,
Sunghwan Yun <sunghwan.yun@samsung.com>,
Mel Gorman <mgorman@suse.de>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Michal Nazarewicz <mina86@mina86.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Christoph Lameter <cl@linux.com>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 1/2] mm/compaction: make isolate_freepages start at pageblock boundary
Date: Thu, 17 Apr 2014 08:43:09 +0900 [thread overview]
Message-ID: <20140416234309.GE27534@bbox> (raw)
In-Reply-To: <1397553507-15330-1-git-send-email-vbabka@suse.cz>
On Tue, Apr 15, 2014 at 11:18:26AM +0200, Vlastimil Babka wrote:
> The compaction freepage scanner implementation in isolate_freepages() starts
> by taking the current cc->free_pfn value as the first pfn. In a for loop, it
> scans from this first pfn to the end of the pageblock, and then subtracts
> pageblock_nr_pages from the first pfn to obtain the first pfn for the next
> for loop iteration.
>
> This means that when cc->free_pfn starts at offset X rather than being aligned
> on pageblock boundary, the scanner will start at offset X in all scanned
> pageblock, ignoring potentially many free pages. Currently this can happen when
> a) zone's end pfn is not pageblock aligned, or
> b) through zone->compact_cached_free_pfn with CONFIG_HOLES_IN_ZONE enabled and
> a hole spanning the beginning of a pageblock
>
> This patch fixes the problem by aligning the initial pfn in isolate_freepages()
> to pageblock boundary. This also allows to replace the end-of-pageblock
> alignment within the for loop with a simple pageblock_nr_pages increment.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Reported-by: Heesub Shin <heesub.shin@samsung.com>
Acked-by: Minchan Kim <minchan@kernel.org>
-stable stuff?
--
Kind regards,
Minchan Kim
next prev parent reply other threads:[~2014-04-16 23:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-03 8:57 [PATCH 1/2] mm/compaction: clean up unused code lines Heesub Shin
2014-04-03 8:57 ` [PATCH 2/2] mm/compaction: fix to initialize free scanner properly Heesub Shin
2014-04-07 14:46 ` Vlastimil Babka
2014-04-15 9:18 ` [PATCH 1/2] mm/compaction: make isolate_freepages start at pageblock boundary Vlastimil Babka
2014-04-15 9:18 ` [PATCH 2/2] mm/compaction: cleanup isolate_freepages() Vlastimil Babka
2014-04-16 1:53 ` Joonsoo Kim
2014-04-16 15:49 ` Rik van Riel
2014-04-17 0:07 ` Minchan Kim
2014-04-21 19:41 ` Andrew Morton
2014-04-21 21:43 ` Vlastimil Babka
2014-04-21 23:53 ` Minchan Kim
2014-04-22 6:33 ` Vlastimil Babka
2014-04-22 6:52 ` Minchan Kim
2014-04-22 13:17 ` Vlastimil Babka
2014-04-23 2:58 ` Joonsoo Kim
2014-04-23 7:30 ` Vlastimil Babka
2014-04-23 13:54 ` Joonsoo Kim
2014-04-23 14:31 ` Vlastimil Babka
2014-04-25 8:29 ` Joonsoo Kim
2014-04-29 8:40 ` Vlastimil Babka
2014-05-01 1:58 ` Michal Nazarewicz
2014-04-16 1:52 ` [PATCH 1/2] mm/compaction: make isolate_freepages start at pageblock boundary Joonsoo Kim
2014-04-16 15:47 ` Rik van Riel
2014-04-16 23:43 ` Minchan Kim [this message]
2014-04-07 14:40 ` [PATCH 1/2] mm/compaction: clean up unused code lines Vlastimil Babka
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