Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932915AbXFEVFt (ORCPT ); Tue, 5 Jun 2007 17:05:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760775AbXFEVFl (ORCPT ); Tue, 5 Jun 2007 17:05:41 -0400 Received: from nz-out-0506.google.com ([64.233.162.229]:39908 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758706AbXFEVFk (ORCPT ); Tue, 5 Jun 2007 17:05:40 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=Xo9qmkUIqCLc47RG9LLkPSOSxkl9xd4DeJKU/FQ+WhAEK7eiJbsKdjquQuD3gJHKaZHbE+R3BhiXz/z89oQ2AgCTTSvepXA7wax4XdtaSeNz1JfjgoqjTE/CpjYxYg+6iQTIubNDVkUZKyAg3lqWyJqOTVRA2DCH2x4gWl8IlnE= Message-ID: Date: Wed, 6 Jun 2007 02:35:39 +0530 From: "Satyam Sharma" To: "Robert P. J. Day" Subject: Re: [PATCH] S390: Replace calls to __get_free_pages() with __get_dma_pages(). Cc: "Linux Kernel Mailing List" , schwidefsky@de.ibm.com, "Andrew Morton" , linux-mm@kvack.org In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1531 Lines: 37 Hi, On 6/6/07, Robert P. J. Day wrote: > > Replace a number of calls to __get_free_pages() with the corresponding > calls to __get_dma_pages(). > [...] > once the __GFP_DMA argument is removed, it does look weird to see > the first argument of just 0. should that be filled in with > GFP_ATOMIC as christopher lameter suggested? Yes, I suppose so ... GFP_ATOMIC can dip into the emergency pools so would also make this code a bit more "robust" than using "0" (== GFP_NOWAIT) and it's not that GFP_ATOMIC "waits" on anything either ... > - (void *)__get_free_pages(__GFP_DMA, > + (void *)__get_dma_pages(0, GFP_NOWAIT == 0, so the macro GFP_NOWAIT is the one to use if you really don't want any change in behaviour (and as the comment above GFP_NOWAIT says, it's much better to use that name than simply specify "0"). Off-topic, but I wonder what are the valid usage cases / scenarios for GFP_NOWAIT? The obvious answer is somebody might want to be a way-too-polite citizen and stay off the emergency pools even from atomic context, but why would anybody want to do /that/ ... [ BTW there are 3 users of GFP_NOWAIT in kernel code, but there could be more that simply specify "0" to get same behaviour. ] Satyam - 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/