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From: Christoph Lameter <cl@linux-foundation.org>
To: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Richard Kennedy <richard@rsk.demon.co.uk>,
	penberg@cs.helsinki.fi, mpm@selenic.com,
	linux-mm <linux-mm@kvack.org>,
	lkml <linux-kernel@vger.kernel.org>, Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH][RFC] slub: increasing order reduces memory usage of some key caches
Date: Wed, 16 Jul 2008 09:46:51 -0500	[thread overview]
Message-ID: <487E09DB.3000205@linux-foundation.org> (raw)
In-Reply-To: <19f34abd0807160733q2594bd9fk268703d2aedc8254@mail.gmail.com>

Vegard Nossum wrote:

> Hm, I don't think so? I thought that those 1 and 2 were not orders,
> but in fact the number of pages. Which seems correct, since now you
> have 4096 / 208 = 19 :-)

Makes sense. So the problem is that for some reason his kernel chose order 0 for dentries. Mine choose order 1 and everything was fine. Maybe related to the number of processors (my box has 8)? We added some logic in 2.6.26 to increase slab sizes if lots of processors are present.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Lameter <cl@linux-foundation.org>
To: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Richard Kennedy <richard@rsk.demon.co.uk>,
	penberg@cs.helsinki.fi, mpm@selenic.com,
	linux-mm <linux-mm@kvack.org>,
	lkml <linux-kernel@vger.kernel.org>, Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH][RFC] slub: increasing order reduces memory usage of some key caches
Date: Wed, 16 Jul 2008 09:46:51 -0500	[thread overview]
Message-ID: <487E09DB.3000205@linux-foundation.org> (raw)
In-Reply-To: <19f34abd0807160733q2594bd9fk268703d2aedc8254@mail.gmail.com>

Vegard Nossum wrote:

> Hm, I don't think so? I thought that those 1 and 2 were not orders,
> but in fact the number of pages. Which seems correct, since now you
> have 4096 / 208 = 19 :-)

Makes sense. So the problem is that for some reason his kernel chose order 0 for dentries. Mine choose order 1 and everything was fine. Maybe related to the number of processors (my box has 8)? We added some logic in 2.6.26 to increase slab sizes if lots of processors are present.

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  reply	other threads:[~2008-07-16 14:47 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-07-16 12:29 [PATCH][RFC] slub: increasing order reduces memory usage of some key caches Richard Kennedy
2008-07-16 12:29 ` Richard Kennedy
2008-07-16 13:21 ` Christoph Lameter
2008-07-16 13:21   ` Christoph Lameter
2008-07-16 13:58   ` Richard Kennedy
2008-07-16 13:58     ` Richard Kennedy
2008-07-16 14:03     ` Christoph Lameter
2008-07-16 14:03       ` Christoph Lameter
2008-07-16 14:30       ` Richard Kennedy
2008-07-16 14:30         ` Richard Kennedy
2008-07-16 14:33       ` Vegard Nossum
2008-07-16 14:33         ` Vegard Nossum
2008-07-16 14:46         ` Christoph Lameter [this message]
2008-07-16 14:46           ` Christoph Lameter
2008-07-18  9:57       ` Richard Kennedy
2008-07-18  9:57         ` Richard Kennedy
2008-07-18 14:17         ` Christoph Lameter
2008-07-18 14:17           ` Christoph Lameter
2008-07-18 14:20         ` Christoph Lameter
2008-07-18 14:20           ` Christoph Lameter
2008-07-18 14:42           ` Richard Kennedy
2008-07-18 14:42             ` Richard Kennedy
2008-07-18 14:55             ` Christoph Lameter
2008-07-18 14:55               ` Christoph Lameter
2008-07-18 15:22               ` Richard Kennedy
2008-07-18 15:22                 ` Richard Kennedy
2008-07-18 17:13                 ` Christoph Lameter
2008-07-18 17:13                   ` Christoph Lameter
2008-07-16 19:52   ` Mel Gorman
2008-07-16 19:52     ` Mel Gorman
2008-07-17  9:48     ` Richard Kennedy
2008-07-17  9:48       ` Richard Kennedy
2008-07-16 15:52 ` Christoph Lameter
2008-07-16 15:52   ` Christoph Lameter
2008-07-16 15:59 ` Christoph Lameter
2008-07-17 10:09   ` Richard Kennedy
2008-07-17 16:56     ` Christoph Lameter
2008-07-18 10:17       ` Richard Kennedy
2008-07-18 14:21         ` Christoph Lameter

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