From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758567AbYKWNEq (ORCPT ); Sun, 23 Nov 2008 08:04:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757369AbYKWNEf (ORCPT ); Sun, 23 Nov 2008 08:04:35 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:56699 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756970AbYKWNEe (ORCPT ); Sun, 23 Nov 2008 08:04:34 -0500 Date: Sun, 23 Nov 2008 14:04:19 +0100 From: Ingo Molnar To: Joerg Roedel Cc: Joerg Roedel , netdev@vger.kernel.org, Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH 03/10] x86: add initialization code for DMA-API debugging Message-ID: <20081123130419.GA570@elte.hu> References: <1227284770-19215-1-git-send-email-joerg.roedel@amd.com> <1227284770-19215-4-git-send-email-joerg.roedel@amd.com> <20081121174348.GB4336@elte.hu> <20081122094807.GK29705@8bytes.org> <20081123112818.GC29663@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081123112818.GC29663@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Another generic suggestion: Why not just replace dma_ops with a debug version? That way it could be a runtime feature based off the already existing DMA op callbacks, without any extra overhead. I'd prefer such a solution much more with an x86 architecture maintainer hat on, because this way distributions could enable this debug feature (with the facility being off by default) without worrying about the wrapping overhead. This would basically be a special variant of stacked DMA ops support. Ingo