From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760243AbXFDSzM (ORCPT ); Mon, 4 Jun 2007 14:55:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759163AbXFDSy6 (ORCPT ); Mon, 4 Jun 2007 14:54:58 -0400 Received: from nic.NetDirect.CA ([216.16.235.2]:35767 "EHLO rubicon.netdirect.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759044AbXFDSy5 (ORCPT ); Mon, 4 Jun 2007 14:54:57 -0400 X-Originating-Ip: 72.143.65.211 Date: Mon, 4 Jun 2007 14:53:19 -0400 (EDT) From: "Robert P. J. Day" X-X-Sender: rpjday@localhost.localdomain To: Christoph Lameter cc: Linux Kernel Mailing List Subject: Re: __get_free_pages: can GFP_DMA omit GFP_KERNEL and GFP_ATOMIC? In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Net-Direct-Inc-MailScanner-Information: Please contact the ISP for more information X-Net-Direct-Inc-MailScanner: Found to be clean X-Net-Direct-Inc-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-16.8, required 5, autolearn=not spam, ALL_TRUSTED -1.80, BAYES_00 -15.00, INIT_RECVD_OUR_AUTH -20.00, RCVD_IN_SORBS_DUL 20.00) X-Net-Direct-Inc-MailScanner-From: rpjday@mindspring.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 4 Jun 2007, Christoph Lameter wrote: > On Sun, 3 Jun 2007, Robert P. J. Day wrote: > > > first, can a call to __get_free_pages to allocate DMA-able > > memory omit specifying either of GFP_KERNEL or GFP_ATOMIC? > > love's book on kernel development strongly suggests you need to > > specify one or the other, but there are a few instances in the > > tree like this: > > Sure that seems to be equivalent to GFP_ATOMIC with no access to > emergency pool memory. > > > and, second, i only noticed this as i was going to submit a > > short patch to replace __get_free_pages calls for DMA-able memory > > with the existing equivalent macro __get_dma_pages. is that still > > considered a worthwhile cleanup? there's not that many examples > > of it, and it would just make things consistent. > > Sure. all right, then some of those __get_free_pages() calls would translate to calls of the form __get_dma_pages(0, ...) -- is that what you're saying? or would it be equivalent and preferable to put GFP_ATOMIC in there just so it looks not so weird? rday -- ======================================================================== Robert P. J. Day Linux Consulting, Training and Annoying Kernel Pedantry Waterloo, Ontario, CANADA http://fsdev.net/wiki/index.php?title=Main_Page ========================================================================