From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 8FC566B0204 for ; Thu, 15 Apr 2010 03:18:26 -0400 (EDT) Message-ID: <4BC6BE78.1030503@kernel.org> Date: Thu, 15 Apr 2010 16:21:28 +0900 From: Tejun Heo MIME-Version: 1.0 Subject: Re: [PATCH 2/6] change alloc function in pcpu_alloc_pages References: <9918f566ab0259356cded31fd1dd80da6cae0c2b.1271171877.git.minchan.kim@gmail.com> <20100413154820.GC25756@csn.ul.ie> <4BC65237.5080408@kernel.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Mel Gorman , Andrew Morton , KAMEZAWA Hiroyuki , Bob Liu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Lameter List-ID: Hello, On 04/15/2010 10:31 AM, Minchan Kim wrote: > Hi, Tejun. >> This being a pretty cold path, I don't really see much benefit in >> converting it to alloc_pages_node_exact(). It ain't gonna make any >> difference. I'd rather stay with the safer / boring one unless >> there's a pressing reason to convert. > > Actually, It's to weed out not-good API usage as well as some > performance gain. But I don't think to need it strongly. > Okay. Please keep in mind about this and correct it if you confirms > it in future. :) Hmm... if most users are converting over to alloc_pages_node_exact(), I think it would be better to convert percpu too. I thought it was a performance optimization (of rather silly kind too). So, this is to weed out -1 node id usage? Wouldn't it be better to update alloc_pages_node() such that it whines once per each caller if it's called with -1 node id and after updating most users convert the warning into WARN_ON_ONCE()? Having two variants for this seems rather extreme to me. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org