From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Tue, 19 Jul 2011 11:59:37 +0100 Subject: [RFC] Improving scalability of smp_mb__[before|after]_clear_bit In-Reply-To: <20110719104308.GD26574@n2100.arm.linux.org.uk> References: <20110719104308.GD26574@n2100.arm.linux.org.uk> Message-ID: <20110719105937.GG26574@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. .#include. . -#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.