Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752633AbWKBDoa (ORCPT ); Wed, 1 Nov 2006 22:44:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752635AbWKBDo3 (ORCPT ); Wed, 1 Nov 2006 22:44:29 -0500 Received: from outbound-sin.frontbridge.com ([207.46.51.80]:21649 "EHLO outbound3-sin-R.bigfish.com") by vger.kernel.org with ESMTP id S1752633AbWKBDo2 convert rfc822-to-8bit (ORCPT ); Wed, 1 Nov 2006 22:44:28 -0500 X-BigFish: V Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: 8BIT Subject: RE: Can Linux live without DMA zone? X-MimeOLE: Produced By Microsoft Exchange V6.5 Date: Thu, 2 Nov 2006 11:43:38 +0800 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Can Linux live without DMA zone? Thread-Index: Acb+JTnnIw5Rjlw7TcuZKVsmYbT2NgAC1E5g From: "Conke Hu" To: "Jun Sun" , X-OriginalArrivalTime: 02 Nov 2006 03:43:43.0136 (UTC) FILETIME=[17B70200:01C6FE31] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1680 Lines: 48 It seems a good idea. Is dma zone is still necessay on most modern computers? Best regards, Conke @ AMD, Inc. -----Original Message----- From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jun Sun Sent: 2006??11??2?? 10:16 To: linux-kernel@vger.kernel.org Subject: Can Linux live without DMA zone? I am trying to reserve a block of memory (>16MB) starting from 0 and hide it from kernel. A consequence is that DMA zone now has size 0. That causes many drivers to grief (OOMs). I see two ways out: 1. Modify individual drivers and convince them not to alloc with GFP_DMA. I have been trying to do this but do not seem to see an end of it. :) 2. Simply lie and increase MAX_DMA_ADDRESS to really big (like 1GB) so that the whole memory region belongs to DMA zone. #2 sounds pretty hackish. I am sure something bad will happen sooner or later (like what?). But so far it appears to be working fine. The fundamental question is: Has anybody tried to run Linux without 0 sized DMA zone before? Am I doing something that nobody has done before (which is something really hard to believe these days with Linux :P)? Cheers. Jun - 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/ - 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/