From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751470Ab0ESFXC (ORCPT ); Wed, 19 May 2010 01:23:02 -0400 Received: from smtp126.mail.ukl.yahoo.com ([77.238.184.57]:41864 "HELO smtp126.mail.ukl.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751289Ab0ESFXA (ORCPT ); Wed, 19 May 2010 01:23:00 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.es; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:Date:From:User-Agent:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=ZGPf/6ZXpn7uzv6zIMamxDDEJu2guCPM/rD+diPjp9bgSDoVltO3oeCaFZ8ioHWLv0JcrzUL+Kcc/w1Yn52kgFF7IOfMd6+XFw8wwiWB1a4v1+o8IxnhZB8GwHzLFG0RMsJxqEEgkV1YnCm55seq6FNvxS/mIW01dybGxFxaQPI= ; X-Yahoo-SMTP: czee06uswBAtfIYshc.kP27UlfEXaxwWNSjJ X-YMail-OSG: N1O.b5oVM1n0yLhXHar2cKu93OwU70kUrgLfGDfVNwpLp0TYjx4wa6o0xOwVRCSTHkcabp7.aRpS9U1X7J.sRlKzrE6ADbA8CxcNzGHzpowY7iAZvfutge_eGH3dVOOUICAvxO5jwgiTAUKED3qMieGJhEL2Qyveijuw9RYc6vgwUxoROZBwi_nrdUQStf89UdD64ij5jv19Aoizy90lPmb9r4N13KhCq6e_fIMIES8pAljkasde0u.Rt.lTuX3W X-Yahoo-Newman-Property: ymail-3 Message-ID: <4BF375AE.7060901@yahoo.es> Date: Wed, 19 May 2010 07:22:54 +0200 From: Albert Herranz User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100423 Thunderbird/3.0.4 MIME-Version: 1.0 To: FUJITA Tomonori CC: konrad.wilk@oracle.com, Ian.Campbell@eu.citrix.com, jeremy@goop.org, linux-kernel@vger.kernel.org, chrisw@sous-sol.org, iommu@lists.linux-foundation.org, dwmw2@infradead.org, linux@arm.linux.org.uk Subject: Re: [PATCH 5/6] swiotlb: Make swiotlb bookkeeping functions visible in the header file. References: <4BEB884B.7030402@yahoo.es> <20100518123010G.fujita.tomonori@lab.ntt.co.jp> <4BF2C5C1.2020807@yahoo.es> <20100519123626P.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20100519123626P.fujita.tomonori@lab.ntt.co.jp> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/19/2010 05:34 AM, FUJITA Tomonori wrote: >> Every single KB counts on the Wii. It has just 24MB of MEM1 and 64MB of MEM2 (discontiguous memory ranges). >> I'm using 1MB for the SWIOTLB for now, but of course that can be further tweaked down. > > You can decrease the swiotlb memory however you can't fix the root > problems of swiotlb: > > - it needs pre-allocated memory > - it can't handle the out-of-pre-allocated memory situation. > Yes, agreed. Although having a dedicated pool _may_ be an advantage on a memory constrained system: it can guarantee swiotlb allocations (as long as the pool has been properly sized) even when the system is using up all memory. > I mean that Wii doesn't boot on the root device on the USB controller, > right? > The current "bootloaders" boot images from the external SD card. But Linux itself can have its root device on a USB storage device. >> I posted (in the past) a patch series [1] in which I made the >> dmabounce code in the ARM architecture tree available to other >> architectures, and used that to implement the needed bouncing >> infrastructure. But I was told then by Russell to use swiotlb >> instead [2]. > > I think that we need to modify swiotlb for embedded archs. Otherwise, > I don't think that swiotlb can replace arm's dmabounce. > > Ok, I'll implement something like that. > Thanks. Looking forward to it :) Cheers, Albert