From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC] Improving scalability of smp_mb__[before|after]_clear_bit
Date: Tue, 19 Jul 2011 11:59:37 +0100 [thread overview]
Message-ID: <20110719105937.GG26574@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110719104308.GD26574@n2100.arm.linux.org.uk>
On Tue, Jul 19, 2011 at 11:43:08AM +0100, Russell King - ARM Linux wrote:
> On Tue, Jul 12, 2011 at 12:34:59AM -0700, heechul Yun wrote:
> > I think L2 cache sync operation, called by mb(), is not necessary for bitops.
> > This patch improves lat_pagefault of lmbench by up to 11% on a A9 SMP.
> > Higher proceesor
> > counts can benefit more.
>
> bitops should only be used on normal memory and not for stuff used for IO,
> so this should be safe.
>
> Could you submit it to the patch system please with Catalins ack?
Oh, you have but yet again the patch is broken by tabs converted to
whitespace:
$ pdb getpatch 6998/1 | tr ' ' '.'
===============================================================================
Patch:.6998/1:.kernel:.use.proper.memory.barriers.for.bitops
From:.Heechul.Yun
-------------------------------------------------------------------------------
.arch/arm/include/asm/bitops.h.|....4.++--
.1.file.changed,.2.insertions(+),.2.deletions(-)
-------------------------------------------------------------------------------
diff.--git.a/arch/arm/include/asm/bitops.h.b/arch/arm/include/asm/bitops.h
index.b4892a0..f428059.100644
---.a/arch/arm/include/asm/bitops.h
+++.b/arch/arm/include/asm/bitops.h
@@.-26,8.+26,8.@@
.#include.<linux/compiler.h>
.#include.<asm/system.h>
.
-#define.smp_mb__before_clear_bit().....mb()
-#define.smp_mb__after_clear_bit()......mb()
+#define.smp_mb__before_clear_bit().....smp_mb()
+#define.smp_mb__after_clear_bit()......smp_mb()
.
./*
..*.These.functions.are.the.basis.of.our.bit.ops.
If you can't fix your mail client not to do this, the patch system gives
you another way to submit - via the web interface where you can simply
attach the patch as a file. That will avoid any messing about with your
mail client.
However, you really should get your mail client fixed so that it doesn't
mess up whitespace in patches.
next prev parent reply other threads:[~2011-07-19 10:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-12 7:34 [RFC] Improving scalability of smp_mb__[before|after]_clear_bit heechul Yun
2011-07-12 10:07 ` Catalin Marinas
2011-07-19 10:43 ` Russell King - ARM Linux
2011-07-19 10:59 ` Russell King - ARM Linux [this message]
2011-07-19 12:52 ` heechul Yun
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