From: Minchan Kim <minchan.kim@gmail.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
akpm@linux-foundation.org, Josh Boyer <jwboyer@redhat.com>,
aarcange@redhat.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm: vmscan: Limit direct reclaim for higher order allocations
Date: Sun, 9 Oct 2011 17:02:55 +0900 [thread overview]
Message-ID: <20111009080255.GC23003@barrios-desktop> (raw)
In-Reply-To: <1318000643-27996-2-git-send-email-mgorman@suse.de>
On Fri, Oct 07, 2011 at 04:17:22PM +0100, Mel Gorman wrote:
> From: Rik van Riel <riel@redhat.com>
>
> When suffering from memory fragmentation due to unfreeable pages,
> THP page faults will repeatedly try to compact memory. Due to the
> unfreeable pages, compaction fails.
>
> Needless to say, at that point page reclaim also fails to create
> free contiguous 2MB areas. However, that doesn't stop the current
> code from trying, over and over again, and freeing a minimum of 4MB
> (2UL << sc->order pages) at every single invocation.
>
> This resulted in my 12GB system having 2-3GB free memory, a
> corresponding amount of used swap and very sluggish response times.
>
> This can be avoided by having the direct reclaim code not reclaim from
> zones that already have plenty of free memory available for compaction.
>
> If compaction still fails due to unmovable memory, doing additional
> reclaim will only hurt the system, not help.
>
> Signed-off-by: Rik van Riel <riel@redhat.com>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
--
Kinds regards,
Minchan Kim
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next prev parent reply other threads:[~2011-10-09 8:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-07 15:17 [PATCH 0/2] Avoid excessive reclaim due to THP Mel Gorman
2011-10-07 15:17 ` [PATCH 1/2] mm: vmscan: Limit direct reclaim for higher order allocations Mel Gorman
2011-10-07 19:32 ` Rik van Riel
2011-10-07 20:18 ` Mel Gorman
2011-10-09 8:02 ` Minchan Kim [this message]
2011-10-07 15:17 ` [PATCH 2/2] mm: Abort reclaim/compaction if compaction can proceed Mel Gorman
2011-10-07 20:07 ` Rik van Riel
2011-10-07 20:24 ` Mel Gorman
2011-10-07 22:42 ` Rik van Riel
2011-10-09 8:04 ` Minchan Kim
2011-10-12 14:57 ` Johannes Weiner
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