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From: Michal Nazarewicz <mina86@mina86.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
	Minchan Kim <minchan@kernel.org>
Cc: linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org,
	linux-kernel@vger.kernel.org,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mel@csn.ul.ie>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: Re: [PATCH] mm: cma: allocate pages from CMA if NR_FREE_PAGES approaches low water mark
Date: Tue, 20 Nov 2012 16:41:12 +0100	[thread overview]
Message-ID: <xa1tk3tgjn8n.fsf@mina86.com> (raw)
In-Reply-To: <50AB987F.30002@samsung.com>

[-- Attachment #1: Type: text/plain, Size: 937 bytes --]

On Tue, Nov 20 2012, Marek Szyprowski wrote:
> Right now running out of 'plain' movable pages is the only possibility to
> get movable pages allocated from CMA. On the other hand running out of
> 'plain' movable pages is very deadly for the system, as movable pageblocks
> are also the main fallbacks for reclaimable and non-movable pages.
>
> Then, once we run out of movable pages and kernel needs non-mobable or
> reclaimable page (what happens quite often), it usually triggers OOM to
> satisfy the memory needs. Such OOM is very strange, especially on a system
> with dozen of megabytes of CMA memory, having most of them free at the OOM
> event. By high memory pressure I mean the high memory usage.

Would it make sense to *always* use MIGRATE_CMA for movable allocations
before MIGRATE_MOVABLE?  Ie. how about this patch (not tested):

------------------------- >8 -------------------------------------------------

  reply	other threads:[~2012-11-20 15:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-12  8:59 Marek Szyprowski
2012-11-14 22:58 ` Andrew Morton
2012-11-19 15:38   ` Marek Szyprowski
2012-11-19 20:43     ` Andrew Morton
2012-11-20  0:01 ` Minchan Kim
2012-11-20 14:49   ` Marek Szyprowski
2012-11-20 15:41     ` Michal Nazarewicz [this message]
2012-11-21  1:05     ` Minchan Kim
2012-11-21 13:07       ` Michal Nazarewicz
2012-11-21 13:25         ` Minchan Kim
2012-11-21 15:50       ` Marek Szyprowski
2012-11-23  4:42         ` Minchan Kim

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