From: Rafael Aquini <aquini@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Richard Davies <richard@arachsys.com>, KVM <kvm@vger.kernel.org>,
QEMU-devel <qemu-devel@nongnu.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Avi Kivity <avi@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Shaohua Li <shli@kernel.org>
Subject: Re: [Qemu-devel] [PATCH 9/9] mm: compaction: Restart compaction from near where it left off
Date: Fri, 21 Sep 2012 14:54:24 -0300 [thread overview]
Message-ID: <20120921175424.GI6665@optiplex.redhat.com> (raw)
In-Reply-To: <1348224383-1499-10-git-send-email-mgorman@suse.de>
On Fri, Sep 21, 2012 at 11:46:23AM +0100, Mel Gorman wrote:
> This is almost entirely based on Rik's previous patches and discussions
> with him about how this might be implemented.
>
> Order > 0 compaction stops when enough free pages of the correct page
> order have been coalesced. When doing subsequent higher order allocations,
> it is possible for compaction to be invoked many times.
>
> However, the compaction code always starts out looking for things to compact
> at the start of the zone, and for free pages to compact things to at the
> end of the zone.
>
> This can cause quadratic behaviour, with isolate_freepages starting at
> the end of the zone each time, even though previous invocations of the
> compaction code already filled up all free memory on that end of the zone.
> This can cause isolate_freepages to take enormous amounts of CPU with
> certain workloads on larger memory systems.
>
> This patch caches where the migration and free scanner should start from on
> subsequent compaction invocations using the pageblock-skip information. When
> compaction starts it begins from the cached restart points and will
> update the cached restart points until a page is isolated or a pageblock
> is skipped that would have been scanned by synchronous compaction.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> Acked-by: Rik van Riel <riel@redhat.com>
> ---
Acked-by: Rafael Aquini <aquini@redhat.com>
next prev parent reply other threads:[~2012-09-21 17:54 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 10:46 [Qemu-devel] [PATCH 0/9] Reduce compaction scanning and lock contention Mel Gorman
2012-09-21 10:46 ` [Qemu-devel] [PATCH 1/9] Revert "mm: compaction: check lock contention first before taking lock" Mel Gorman
2012-09-21 17:46 ` Rafael Aquini
2012-09-21 10:46 ` [Qemu-devel] [PATCH 2/9] Revert "mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long-fix" Mel Gorman
2012-09-21 17:47 ` Rafael Aquini
2012-09-21 10:46 ` [Qemu-devel] [PATCH 3/9] Revert "mm: compaction: abort compaction loop if lock is contended or run too long" Mel Gorman
2012-09-21 17:48 ` Rafael Aquini
2012-09-21 10:46 ` [Qemu-devel] [PATCH 4/9] mm: compaction: Abort compaction loop if lock is contended or run too long Mel Gorman
2012-09-21 17:50 ` Rafael Aquini
2012-09-21 21:31 ` Andrew Morton
2012-09-25 7:34 ` Minchan Kim
2012-09-21 10:46 ` [Qemu-devel] [PATCH 5/9] mm: compaction: Acquire the zone->lru_lock as late as possible Mel Gorman
2012-09-21 17:51 ` Rafael Aquini
2012-09-25 7:05 ` Minchan Kim
2012-09-25 7:51 ` Mel Gorman
2012-09-25 8:13 ` Minchan Kim
2012-09-25 21:39 ` Andrew Morton
2012-09-26 0:23 ` Minchan Kim
2012-09-26 10:17 ` Mel Gorman
2012-09-21 10:46 ` [Qemu-devel] [PATCH 6/9] mm: compaction: Acquire the zone->lock " Mel Gorman
2012-09-21 17:52 ` Rafael Aquini
2012-09-21 21:35 ` Andrew Morton
2012-09-24 8:52 ` Mel Gorman
2012-09-25 7:36 ` Minchan Kim
2012-09-25 7:35 ` Minchan Kim
2012-09-21 10:46 ` [Qemu-devel] [PATCH 7/9] Revert "mm: have order > 0 compaction start off where it left" Mel Gorman
2012-09-21 17:52 ` Rafael Aquini
2012-09-25 7:37 ` Minchan Kim
2012-09-21 10:46 ` [Qemu-devel] [PATCH 8/9] mm: compaction: Cache if a pageblock was scanned and no pages were isolated Mel Gorman
2012-09-21 17:53 ` Rafael Aquini
2012-09-21 21:36 ` Andrew Morton
2012-09-24 9:39 ` Mel Gorman
2012-09-24 21:26 ` Andrew Morton
2012-09-25 9:12 ` Mel Gorman
2012-09-25 20:03 ` Andrew Morton
2012-09-27 12:06 ` [Qemu-devel] [PATCH] mm: compaction: cache if a pageblock was scanned and no pages were isolated -fix2 Mel Gorman
2012-09-27 13:12 ` [Qemu-devel] [PATCH 8/9] mm: compaction: Cache if a pageblock was scanned and no pages were isolated Mel Gorman
2012-09-26 0:49 ` Minchan Kim
2012-09-27 12:14 ` Mel Gorman
2012-09-21 10:46 ` [Qemu-devel] [PATCH 9/9] mm: compaction: Restart compaction from near where it left off Mel Gorman
2012-09-21 17:54 ` Rafael Aquini [this message]
2012-09-21 13:51 ` [Qemu-devel] [PATCH 0/9] Reduce compaction scanning and lock contention Rik van Riel
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