Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761833AbXFBQrS (ORCPT ); Sat, 2 Jun 2007 12:47:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757670AbXFBQrI (ORCPT ); Sat, 2 Jun 2007 12:47:08 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39027 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757542AbXFBQrH (ORCPT ); Sat, 2 Jun 2007 12:47:07 -0400 Date: Sat, 2 Jun 2007 18:47:04 +0200 From: Andi Kleen To: Muli Ben-Yehuda Cc: Andi Kleen , Rik van Riel , Andrew Vasquez , Christoph Hellwig , linux-kernel Subject: Re: [PATCH] quiet down swiotlb warnings Message-ID: <20070602164704.GQ7217@one.firstfloor.org> References: <20070601181225.GA16460@infradead.org> <20070601193703.GI7217@one.firstfloor.org> <466075D1.8080807@redhat.com> <20070601194734.GJ7217@one.firstfloor.org> <20070601200049.GK12143@andrew-vasquezs-computer.local> <20070601201444.GK7217@one.firstfloor.org> <46607F96.7060200@redhat.com> <20070601202601.GM7217@one.firstfloor.org> <20070602152146.GE4342@rhun.haifa.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070602152146.GE4342@rhun.haifa.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 962 Lines: 22 On Sat, Jun 02, 2007 at 06:21:46PM +0300, Muli Ben-Yehuda wrote: > On Fri, Jun 01, 2007 at 10:26:01PM +0200, Andi Kleen wrote: > > > Normally swiotlb doesn't even try to bounce when dma mask is <= > > end_pfn so something must be very wrong in your kernel. It > > definitely isn't a mainline kernel. If this happens in Xen then Xen > > just needs fixing -- it should not try to bounce when the normal > > kernel wouldn't. > > Xen needs to bounce when the requested buffer is not contiguous in > machine memory (and indeed uses swiotlb for that). Then it should just restrict the sg list merging at the block layer to never merge into anything larger than a page. Then this cannot happen or only very rarely. -Andi - 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/