From: Minchan Kim <minchan@kernel.org>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-mm@kvack.org, mgorman@suse.de,
Kyungmin Park <kyungmin.park@samsung.com>
Subject: Re: [PATCH 1/2] mm: compaction: try harder to isolate free pages
Date: Fri, 6 Apr 2012 17:51:30 +0900 [thread overview]
Message-ID: <CAEwNFnDuPX5a59YrFO1FGHoQSj4j=hNRd45vgjDTzCKTh9wugg@mail.gmail.com> (raw)
In-Reply-To: <201204061021.39656.b.zolnierkie@samsung.com>
On Fri, Apr 6, 2012 at 5:21 PM, Bartlomiej Zolnierkiewicz
<b.zolnierkie@samsung.com> wrote:
> On Friday 06 April 2012 08:40:56 Minchan Kim wrote:
>> On Fri, Apr 6, 2012 at 1:32 AM, Bartlomiej Zolnierkiewicz <
>> b.zolnierkie@samsung.com> wrote:
>>
>> > In isolate_freepages() check each page in a pageblock
>> > instead of checking only first pages of pageblock_nr_pages
>> > intervals (suitable_migration_target(page) is called before
>> > isolate_freepages_block() so if page is "unsuitable" whole
>> > pageblock_nr_pages pages will be ommited from the check).
>> > It greatly improves possibility of finding free pages to
>> > isolate during compaction_alloc() phase.
>> >
>>
>> I doubt how this can help keeping free pages.
>> Now, compaction works by pageblock_nr_pages unit so although you work by
>> per page, all pages in a block would have same block type.
>> It means we can't pass suitable_migration_target. No?
>
> suitable_migration_target() only checks first page of pageblock_nr_pages
> block (1024 normal 4KiB pages in my test case cause there is no hugepage
> support on ARM) and pages in pageblock_nr_pages block can have different
> types otherwise I would not see improvement from this patch.
How?
pages in a block should be same type.
--
Kind regards,
Minchan Kim
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next prev parent reply other threads:[~2012-04-06 8:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-05 16:32 [PATCH 0/2] mm: compaction: improve free pages selection Bartlomiej Zolnierkiewicz
2012-04-05 16:32 ` [PATCH 1/2] mm: compaction: try harder to isolate free pages Bartlomiej Zolnierkiewicz
2012-04-06 6:40 ` Minchan Kim
2012-04-06 8:21 ` Bartlomiej Zolnierkiewicz
2012-04-06 8:51 ` Minchan Kim [this message]
2012-04-10 10:38 ` Mel Gorman
2012-04-12 5:42 ` Mel Gorman
2012-04-05 16:32 ` [PATCH 2/2] mm: compaction: allow isolation of lower order buddy pages Bartlomiej Zolnierkiewicz
2012-04-05 21:46 ` David Rientjes
2012-04-06 8:38 ` Bartlomiej Zolnierkiewicz
2012-04-06 6:45 ` Minchan Kim
2012-04-10 10:40 ` Mel Gorman
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