From: Christoph Lameter <cl@linux-foundation.org>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org,
Christoph Lameter <cl@linux-foundation.org>,
linux-mm@kvack.org, jeremy@goop.org, ebiederm@xmission.com,
travis@sgi.com, herbert@gondor.apana.org.au, xemul@openvz.org,
penberg@cs.helsinki.fi
Subject: [patch 3/3] Increase default reserve percpu area
Date: Fri, 19 Sep 2008 13:37:06 -0700 [thread overview]
Message-ID: <20080919203724.474751340@quilx.com> (raw)
In-Reply-To: <20080919203703.312007962@quilx.com>
[-- Attachment #1: cpu_alloc_increase_percpu_default --]
[-- Type: text/plain, Size: 1126 bytes --]
SLUB now requires a portion of the per cpu reserve. There are on average
about 70 real slabs on a system (aliases do not count) and each needs 12 bytes
of per cpu space. Thats 840 bytes. In debug mode all slabs will be real slabs
which will make us end up with 150 -> 1800. Give it some slack and add 2000
bytes to the default size.
Things work fine without this patch but then slub will reduce the percpu reserve
for modules.
Also define a reserve if CONFIG_MODULES is off.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Index: linux-2.6/include/linux/percpu.h
===================================================================
--- linux-2.6.orig/include/linux/percpu.h 2008-09-19 15:04:21.000000000 -0500
+++ linux-2.6/include/linux/percpu.h 2008-09-19 15:05:31.000000000 -0500
@@ -38,9 +38,9 @@
/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
#ifndef PERCPU_AREA_SIZE
#ifdef CONFIG_MODULES
-#define PERCPU_RESERVE_SIZE 8192
+#define PERCPU_RESERVE_SIZE 10000
#else
-#define PERCPU_RESERVE_SIZE 0
+#define PERCPU_RESERVE_SIZE 2000
#endif
#define PERCPU_AREA_SIZE \
--
next prev parent reply other threads:[~2008-09-19 20:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-19 20:37 [patch 0/3] Cpu alloc slub support: Replace percpu allocator in slub.c Christoph Lameter
2008-09-19 20:37 ` [patch 1/3] cpu alloc: Use in slub Christoph Lameter
2008-09-19 20:37 ` [patch 2/3] cpu alloc: Remove slub fields Christoph Lameter
2008-10-01 17:53 ` Pekka Enberg
2008-10-02 16:21 ` Christoph Lameter
2008-09-19 20:37 ` Christoph Lameter [this message]
2008-09-19 22:02 ` [patch 3/3] Increase default reserve percpu area Pekka Enberg
2008-09-19 22:07 ` Pekka Enberg
2008-09-19 21:57 ` [patch 0/3] Cpu alloc slub support: Replace percpu allocator in slub.c Pekka Enberg
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