Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755459AbXFKTft (ORCPT ); Mon, 11 Jun 2007 15:35:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752577AbXFKTfl (ORCPT ); Mon, 11 Jun 2007 15:35:41 -0400 Received: from wa-out-1112.google.com ([209.85.146.180]:17162 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752133AbXFKTfk convert rfc822-to-8bit (ORCPT ); Mon, 11 Jun 2007 15:35:40 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=KDSgjG5dgxhGyFKpXgdo9QoNNS85Q6dTQNm7AHjxBYauw/CopX1jQr5KcSaXQr83YrHf8P1tRbM3zAehB+UQaZ3YibQUG9NMo3NElFXxpvHxet/4/QB9jdPTOYVaLfwQdqAA3IyTAMZl3fAABZPYHJXjL7lHVorUmD0NU6rk/PA= Message-ID: <1defaf580706111235p7da29d25xc33d221134f3f7a8@mail.gmail.com> Date: Mon, 11 Jun 2007 21:35:39 +0200 From: "=?ISO-8859-1?Q?H=E5vard_Skinnemoen?=" To: "Christoph Lameter" Subject: Re: kernel BUG at mm/slub.c:3689! Cc: "Haavard Skinnemoen" , "Linux Kernel" , "David Brownell" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8BIT Content-Disposition: inline References: <20070611161926.2a9f8efd@dhcp-255-175.norway.atmel.com> <1defaf580706110943q56d83939t9ab6331cc45b4810@mail.gmail.com> <1defaf580706111011w641b26fbu68d6d34028f6e953@mail.gmail.com> <1defaf580706111122n78ab46c3sda05cbd4ace97319@mail.gmail.com> <1defaf580706111204v35b4dcc9j5dc68e722bd384b1@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1332 Lines: 29 On 6/11/07, Christoph Lameter wrote: > On Mon, 11 Jun 2007, H?vard Skinnemoen wrote: > > I think it's best to ensure that memory returned by kmalloc() actually > > can be used for DMA. I used to work around this problem in the SPI > > controller driver by using a temporary DMA buffer when possible > > misalignment was detected, but David Brownell said it was the wrong > > way to do it and pointed at the above paragraph. > > Well there are various ways of doing DMA. Memory returned can be used for > DMA but it may not be suitable for your DMA device if that device has > issues like alignment or physical address size restrictions. Yes, that's true. If the DMA device has such restrictions, it probably needs to be addressed elsewhere. My goal here is to make sure that kmalloc()'ed memory is suitable for DMA as far as the CPU and caches are concerned. > We should probably make the minimum slab size dependent on > ARCH_KMALLOC_MINALIGN. There is no point in having smaller slabs anyways. > They will all have the same size. Sounds reasonable to me. Haavard - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/