From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>,
Mel Gorman <mgorman@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Colin King <colin.king@canonical.com>,
Raghavendra D Prabhu <raghu.prabhu13@gmail.com>,
Jan Kara <jack@suse.cz>, Chris Mason <chris.mason@oracle.com>,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-ext4 <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH 2/4] mm: slub: Do not wake kswapd for SLUBs speculative high-order allocations
Date: Wed, 18 May 2011 12:21:08 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1105181218520.12423@router.home> (raw)
In-Reply-To: <4DD36299.8000108@cs.helsinki.fi>
On Wed, 18 May 2011, Pekka Enberg wrote:
> On 5/17/11 12:10 AM, David Rientjes wrote:
> > On Fri, 13 May 2011, Mel Gorman wrote:
> >
> > > To avoid locking and per-cpu overhead, SLUB optimisically uses
> > > high-order allocations and falls back to lower allocations if they
> > > fail. However, by simply trying to allocate, kswapd is woken up to
> > > start reclaiming at that order. On a desktop system, two users report
> > > that the system is getting locked up with kswapd using large amounts
> > > of CPU. Using SLAB instead of SLUB made this problem go away.
> > >
> > > This patch prevents kswapd being woken up for high-order allocations.
> > > Testing indicated that with this patch applied, the system was much
> > > harder to hang and even when it did, it eventually recovered.
> > >
> > > Signed-off-by: Mel Gorman<mgorman@suse.de>
> > Acked-by: David Rientjes<rientjes@google.com>
>
> Christoph? I think this patch is sane although the original rationale was to
> workaround kswapd problems.
I am mostly fine with it. The concerns that I have is if there is a
large series of high order allocs then at some point you would want
kswapd to be triggered instead of high order allocs constantly failing.
Can we have a "trigger once in a while" functionality?
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next prev parent reply other threads:[~2011-05-18 17:21 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-13 14:03 [PATCH 0/4] Reduce impact to overall system of SLUB using high-order allocations V2 Mel Gorman
2011-05-13 14:03 ` [PATCH 1/4] mm: vmscan: Correct use of pgdat_balanced in sleeping_prematurely Mel Gorman
2011-05-13 14:28 ` Johannes Weiner
2011-05-14 16:30 ` Minchan Kim
2011-05-16 14:30 ` Rik van Riel
2011-05-13 14:03 ` [PATCH 2/4] mm: slub: Do not wake kswapd for SLUBs speculative high-order allocations Mel Gorman
2011-05-16 21:10 ` David Rientjes
2011-05-18 6:09 ` Pekka Enberg
2011-05-18 17:21 ` Christoph Lameter [this message]
2011-05-13 14:03 ` [PATCH 3/4] mm: slub: Do not take expensive steps " Mel Gorman
2011-05-16 21:16 ` David Rientjes
2011-05-17 8:42 ` Mel Gorman
2011-05-17 13:51 ` Christoph Lameter
2011-05-17 16:22 ` Mel Gorman
2011-05-17 17:52 ` Christoph Lameter
2011-05-17 19:35 ` David Rientjes
2011-05-17 19:31 ` David Rientjes
2011-05-13 14:03 ` [PATCH 4/4] mm: vmscan: If kswapd has been running too long, allow it to sleep Mel Gorman
2011-05-15 10:27 ` KOSAKI Motohiro
2011-05-16 4:21 ` James Bottomley
2011-05-16 5:04 ` Minchan Kim
2011-05-16 8:45 ` Mel Gorman
2011-05-16 8:58 ` Minchan Kim
2011-05-16 10:27 ` Mel Gorman
2011-05-16 23:50 ` Minchan Kim
2011-05-17 0:48 ` Minchan Kim
2011-05-17 10:38 ` Mel Gorman
2011-05-17 13:50 ` Colin Ian King
2011-05-17 16:15 ` [PATCH] mm: vmscan: Correctly check if reclaimer should schedule during shrink_slab Mel Gorman
2011-05-18 0:45 ` KOSAKI Motohiro
2011-05-19 0:03 ` Minchan Kim
2011-05-19 0:09 ` Minchan Kim
2011-05-19 11:36 ` Colin Ian King
2011-05-20 0:06 ` Minchan Kim
2011-05-18 4:19 ` [PATCH 4/4] mm: vmscan: If kswapd has been running too long, allow it to sleep Minchan Kim
2011-05-18 7:39 ` Colin Ian King
2011-05-18 4:09 ` James Bottomley
2011-05-18 1:05 ` KOSAKI Motohiro
2011-05-18 5:44 ` Minchan Kim
2011-05-18 6:05 ` KOSAKI Motohiro
2011-05-18 9:58 ` Mel Gorman
2011-05-18 22:55 ` Minchan Kim
2011-05-18 23:54 ` KOSAKI Motohiro
2011-05-18 0:26 ` KOSAKI Motohiro
2011-05-18 9:57 ` Mel Gorman
2011-05-16 8:45 ` Mel Gorman
2011-05-16 14:30 ` Rik van Riel
2011-05-13 15:19 ` [PATCH 0/4] Reduce impact to overall system of SLUB using high-order allocations V2 James Bottomley
2011-05-13 15:52 ` Mel Gorman
2011-05-13 15:21 ` Christoph Lameter
2011-05-13 15:43 ` Mel Gorman
2011-05-14 8:34 ` Colin Ian King
2011-05-16 8:37 ` Mel Gorman
2011-05-16 11:24 ` Colin Ian King
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