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Message-Id: <20080820204005.12F3.KOSAKI.MOTOHIRO@jp.fujitsu.com>
Date: Wed, 20 Aug 2008 20:46:07 +0900
From: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To: Christoph Lameter <cl@...ux-foundation.org>
Cc: kosaki.motohiro@...fujitsu.com, Matthew Wilcox <matthew@....cx>,
Pekka Enberg <penberg@...helsinki.fi>,
akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org, Mel Gorman <mel@...net.ie>,
andi@...stfloor.org, Rik van Riel <riel@...hat.com>
Subject: Re: No, really, stop trying to delete slab until you've finished making slub perform as well
> KOSAKI Motohiro wrote:
>
> > IOW, My box didn't happend performance regression.
> > but I think it isn't typical.
>
> Well that is typical for small NUMA system. Maybe this patch will fix it for
> now? Large systems can be tuned by setting the ratio lower.
>
>
> Subject: slub/NUMA: Disable remote node defragmentation by default
>
> Switch remote node defragmentation off by default. The current settings can
> cause excessive node local allocations with hackbench. (Note that this feature
> is not related to slab defragmentation).
OK.
I confirmed this patch works well.
Tested-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
>
> Signed-off-by: Christoph Lameter <cl@...ux-foundation.org>
>
> ---
> mm/slub.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c 2008-08-19 06:45:54.732348449 -0700
> +++ linux-2.6/mm/slub.c 2008-08-19 06:46:12.442348249 -0700
> @@ -2312,7 +2312,7 @@ static int kmem_cache_open(struct kmem_c
>
> s->refcount = 1;
> #ifdef CONFIG_NUMA
> - s->remote_node_defrag_ratio = 100;
> + s->remote_node_defrag_ratio = 1000;
> #endif
> if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
> goto error;
> @@ -4058,7 +4058,7 @@ static ssize_t remote_node_defrag_ratio_
> if (err)
> return err;
>
> - if (ratio < 100)
> + if (ratio <= 100)
> s->remote_node_defrag_ratio = ratio * 10;
>
> return length;
--
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