Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759400AbYLQIrh (ORCPT ); Wed, 17 Dec 2008 03:47:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753567AbYLQIr0 (ORCPT ); Wed, 17 Dec 2008 03:47:26 -0500 Received: from vpn.id2.novell.com ([195.33.99.129]:27915 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751577AbYLQIr0 convert rfc822-to-8bit (ORCPT ); Wed, 17 Dec 2008 03:47:26 -0500 Message-Id: <4948CAC3.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 8.0.0 Date: Wed, 17 Dec 2008 08:47:47 +0000 From: "Jan Beulich" To: "FUJITA Tomonori" Cc: , , , , , , Subject: Re: [PATCH 00 of 14] swiotlb/x86: lay groundwork for xen dom0 useof swiotlb References: <20081216203513.GA14787@elte.hu> <20081217142637V.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20081217142637V.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >I think that the whole patchset is against the swiotlb design. swiotlb >is designed to be used as a library. Each architecture implements the >own swiotlb by using swiotlb library >(e.g. arch/x86/kernel/pci-swiotlb_64.c). If it is a library, then it should be prepared to serve all possible users. >For example, adding the following code (9/14) for just Xen that the >majority of swiotbl users (x86_64 and IA64) don't need to the library >is against the design. "Don't" in terms of "currently don't": Once x86-64 wants to support more than 46 physical address bits, it's not impossible that this would lead to CONFIG_HIGHMEM getting introduced there, and then it'll be helpful that the code is already prepared to deal with that case. After all, the code portion in question ought to compile to nothing if !CONFIG_HIGHMEM. Jan -- 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/