From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
linux-mm@kvack.org, Minchan Kim <minchan@kernel.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>
Subject: Re: [PATCH v3] mm: compaction: handle incorrect Unmovable type pageblocks
Date: Thu, 26 Apr 2012 14:52:56 -0400 [thread overview]
Message-ID: <4F999988.802@redhat.com> (raw)
In-Reply-To: <20120426164713.GG15299@suse.de>
On 04/26/2012 12:47 PM, Mel Gorman wrote:
> Instead of COMPACT_ASYNC_PARTIAL and COMPACT_ASYNC_FULL should we have
> COMPACT_ASYNC_MOVABLE and COMPACT_ASYNC_UNMOVABLE? The first pass from
> the page allocator (COMPACT_ASYNC_MOVABLE) would only consider MOVABLE
> blocks as migration targets. The second pass (COMPACT_ASYNC_UNMOVABLE)
> would examine UNMOVABLE blocks, rescue them and use what blocks it
> rescues as migration targets. The third pass (COMPACT_SYNC) would work
> as it does currently. kswapd would only ever use COMPACT_ASYNC_MOVABLE.
>
> That would avoid rescanning the movable blocks uselessly on the second
> pass but should still work for Bartlomiej's workload.
>
> What do you think?
This makes sense.
>> In other words, could it be better to always try to
>> rescue the unmovable blocks?
>
> I do not think we should always scan within unmovable blocks on the
> first pass. I strongly suspect it would lead to excessive amounts of CPU
> time spent in mm/compaction.c.
Maybe my systems are not typical. I have not seen
more than about 10% of the memory blocks marked as
unmovable in my system.
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next prev parent reply other threads:[~2012-04-26 18:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-26 8:15 [PATCH v3] mm: compaction: handle incorrect Unmovable type pageblocks Bartlomiej Zolnierkiewicz
2012-04-26 14:36 ` Mel Gorman
2012-04-26 15:53 ` Rik van Riel
2012-04-26 16:47 ` Mel Gorman
2012-04-26 18:52 ` Rik van Riel [this message]
2012-04-27 9:45 ` Mel Gorman
2012-04-27 0:58 ` Minchan Kim
2012-04-27 9:56 ` Mel Gorman
2012-04-30 2:44 ` Minchan Kim
2012-04-30 8:31 ` Mel Gorman
2012-04-30 8:55 ` Minchan Kim
2012-04-30 9:16 ` Mel Gorman
2012-04-26 15:42 ` Rik van Riel
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