From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pekka Enberg Subject: Re: [PATCH v3] ad7877: keep dma rx buffers in seperate cache lines Date: Tue, 11 May 2010 09:42:03 +0300 Message-ID: References: <1273487642-2169-1-git-send-email-os@emlix.com> <1273488154-2993-1-git-send-email-os@emlix.com> <20100510142225.4bf215ef.akpm@linux-foundation.org> <20100511060547.GA9644@core.coreip.homeip.net> <20100511062110.GB9644@core.coreip.homeip.net> <20100511063309.GC9644@core.coreip.homeip.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:39835 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932354Ab0EKGmG (ORCPT ); Tue, 11 May 2010 02:42:06 -0400 In-Reply-To: <20100511063309.GC9644@core.coreip.homeip.net> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: Mike Frysinger , Andrew Morton , Oskar Schirmer , Michael Hennerich , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, =?ISO-8859-1?Q?Daniel_Gl=F6ckner?= , Oliver Schneidewind , Johannes Weiner , Christoph Lameter , Nick Piggin , David Rientjes , Matt Mackall Hi Dmitry, On Tue, May 11, 2010 at 9:33 AM, Dmitry Torokhov wrote: >> what guarantee exactly do you have for that statement ? > > The data is kmalloced, kmalloc aligns on cacheline boundary AFAIK which > means that next kmalloc data chunk will not share "our" cacheline. No, there are no such guarantees. kmalloc() aligns on ARCH_KMALLOC_MINALIGN or ARCH_SLAB_MINALIGN depending on which is bigger but beyond that, there are no guarantees. You can, of course, use kmem_cache_create() with SLAB_HWCACHE_ALIGN to align on cacheline boundary. Pekka