From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Johannes Weiner <jw@emlix.com>
Cc: "Mike Frysinger" <vapier.adi@gmail.com>,
"Christoph Lameter" <cl@linux.com>,
"Pekka Enberg" <penberg@cs.helsinki.fi>,
"Matt Mackall" <mpm@selenic.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Oskar Schirmer" <os@emlix.com>,
"Michael Hennerich" <Michael.Hennerich@analog.com>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
"Daniel Glöckner" <dg@emlix.com>,
"Oliver Schneidewind" <osw@emlix.com>,
"Nick Piggin" <npiggin@suse.de>,
"David Rientjes" <rientjes@google.com>,
"David Brownell" <dbrownell@users.sourceforge.net>,
"Grant Likely" <grant.likely@secretlab.ca>
Subject: Re: [PATCH v3] ad7877: keep dma rx buffers in seperate cache lines
Date: Tue, 11 May 2010 14:53:59 -0700 [thread overview]
Message-ID: <20100511215359.GF7396@core.coreip.homeip.net> (raw)
In-Reply-To: <20100511214836.GH1726@emlix.com>
On Tue, May 11, 2010 at 11:48:36PM +0200, Johannes Weiner wrote:
> On Tue, May 11, 2010 at 04:54:41PM -0400, Mike Frysinger wrote:
> > does the phrase "DMA safe buffer" imply cache alignment ?
>
> I guess that depends on the architectural requirements. On x86,
> apparently, not so much. On ARM, probably yes, as it's the
> requirement to properly maintain coherency.
It looks liek ARM (and a few others) do this:
[dtor@hammer work]$ grep -r ARCH_KMALLOC_MINALIGN arch/
arch/sh/include/asm/page.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES
arch/frv/include/asm/mem-layout.h:#define ARCH_KMALLOC_MINALIGN 8
arch/powerpc/include/asm/page_32.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES
arch/arm/include/asm/cache.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES
arch/microblaze/include/asm/page.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES
arch/mips/include/asm/mach-tx49xx/kmalloc.h: * All happy, no need to define ARCH_KMALLOC_MINALIGN
arch/mips/include/asm/mach-ip27/kmalloc.h: * All happy, no need to define ARCH_KMALLOC_MINALIGN
arch/mips/include/asm/mach-ip32/kmalloc.h:#define ARCH_KMALLOC_MINALIGN 32
arch/mips/include/asm/mach-ip32/kmalloc.h:#define ARCH_KMALLOC_MINALIGN 128
arch/mips/include/asm/mach-generic/kmalloc.h:#define ARCH_KMALLOC_MINALIGN 128
arch/avr32/include/asm/cache.h:#define ARCH_KMALLOC_MINALIGN L1_CACHE_BYTES
--
Dmitry
next prev parent reply other threads:[~2010-05-11 21:54 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 10:37 [PATCH] ad7877: fix spi word size to 16 bit Oskar Schirmer
2010-05-06 10:37 ` [PATCH] ad7877: keep dma rx buffers in seperate cache lines Oskar Schirmer
2010-05-06 18:46 ` Mike Frysinger
2010-05-07 10:15 ` Oskar Schirmer
2010-05-07 18:28 ` Mike Frysinger
2010-05-08 22:32 ` Johannes Weiner
2010-05-09 4:45 ` Mike Frysinger
2010-05-09 8:50 ` Oskar Schirmer
2010-05-07 12:07 ` Johannes Weiner
2010-05-10 10:34 ` [PATCH v2] " Oskar Schirmer
2010-05-10 10:42 ` [PATCH v3] " Oskar Schirmer
2010-05-10 16:39 ` Mike Frysinger
2010-05-10 20:54 ` Dmitry Torokhov
2010-05-10 21:22 ` Andrew Morton
2010-05-10 21:27 ` Mike Frysinger
2010-05-11 6:05 ` Dmitry Torokhov
2010-05-11 6:11 ` Mike Frysinger
2010-05-11 3:20 ` Andrew Morton
2010-05-11 6:21 ` Dmitry Torokhov
2010-05-11 6:23 ` Mike Frysinger
2010-05-11 6:33 ` Dmitry Torokhov
2010-05-11 6:37 ` Mike Frysinger
2010-05-11 6:42 ` Pekka Enberg
2010-05-11 13:57 ` Christoph Lameter
2010-05-11 16:52 ` Dmitry Torokhov
2010-05-11 17:31 ` Mike Frysinger
2010-05-11 18:59 ` Pekka Enberg
2010-05-11 20:03 ` Mike Frysinger
2010-05-11 20:07 ` Matt Mackall
2010-05-11 20:10 ` Mike Frysinger
2010-05-11 20:21 ` Christoph Lameter
2010-05-11 20:34 ` Mike Frysinger
2010-05-11 20:38 ` Pekka Enberg
2010-05-11 20:43 ` Mike Frysinger
2010-05-11 20:47 ` Pekka Enberg
2010-05-13 6:21 ` Paul Mundt
2010-05-11 20:46 ` Christoph Lameter
2010-05-11 20:54 ` Mike Frysinger
2010-05-11 21:01 ` Pekka Enberg
2010-05-11 21:11 ` Mike Frysinger
2010-05-12 1:58 ` FUJITA Tomonori
[not found] ` <20100511214836.GH1726@emlix.com>
2010-05-11 21:53 ` Dmitry Torokhov [this message]
2010-05-11 22:39 ` Mike Frysinger
2010-05-12 2:07 ` [LKML] " Marc Gauthier
2010-05-12 3:03 ` Nick Piggin
2010-05-12 3:23 ` FUJITA Tomonori
2010-05-12 4:35 ` Mike Frysinger
2010-05-12 5:28 ` FUJITA Tomonori
2010-05-12 14:37 ` Mike Frysinger
2010-05-12 18:11 ` Dmitry Torokhov
2010-05-12 18:28 ` Mike Frysinger
2010-05-12 10:36 ` Johannes Weiner
2010-05-12 12:35 ` Marc Gauthier
2010-05-12 14:36 ` Mike Frysinger
2010-05-19 12:48 ` David Woodhouse
2010-05-19 13:07 ` Nick Piggin
2010-05-19 13:17 ` David Woodhouse
2010-05-19 13:36 ` Nick Piggin
2010-05-19 13:44 ` Johannes Weiner
2010-05-19 13:52 ` Nick Piggin
2010-05-19 14:38 ` FUJITA Tomonori
2010-05-19 14:58 ` David Woodhouse
2010-05-20 4:42 ` FUJITA Tomonori
2010-05-19 16:37 ` Dmitry Torokhov
2010-05-19 15:00 ` Johannes Weiner
2010-05-17 6:12 ` Michal Simek
2010-05-19 13:00 ` David Woodhouse
2010-05-11 22:37 ` Alan Cox
2010-05-11 20:22 ` Pekka Enberg
2010-05-11 14:12 ` Oskar Schirmer
2010-05-06 11:18 ` [PATCH] ad7877: fix spi word size to 16 bit Hennerich, Michael
2010-05-06 18:26 ` Mike Frysinger
2010-05-07 9:41 ` Daniel Glöckner
2010-05-07 18:23 ` Mike Frysinger
2010-05-13 7:53 ` Dmitry Torokhov
2010-05-15 18:15 ` Oskar Schirmer
2010-05-16 19:25 ` Mike Frysinger
2010-05-17 7:29 ` Oskar Schirmer
2010-05-17 8:14 ` Hennerich, Michael
2010-05-17 8:41 ` Oskar Schirmer
2010-05-17 23:49 ` Mike Frysinger
2010-05-18 0:18 ` H Hartley Sweeten
2010-05-18 8:32 ` Oskar Schirmer
2010-05-18 9:37 ` Daniel Glöckner
2010-05-18 8:34 ` [PATCH v2] " Oskar Schirmer
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