From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id CFFDA6B01EF for ; Sun, 18 Apr 2010 11:54:47 -0400 (EDT) Received: by gwb15 with SMTP id 15so2207732gwb.14 for ; Sun, 18 Apr 2010 08:54:45 -0700 (PDT) Subject: Re: [PATCH 2/6] change alloc function in pcpu_alloc_pages From: Minchan Kim In-Reply-To: References: <9918f566ab0259356cded31fd1dd80da6cae0c2b.1271171877.git.minchan.kim@gmail.com> <4BC65237.5080408@kernel.org> <4BC6BE78.1030503@kernel.org> <4BC6CB30.7030308@kernel.org> <4BC6E581.1000604@kernel.org> <4BC6FBC8.9090204@kernel.org> Content-Type: text/plain; charset="UTF-8" Date: Mon, 19 Apr 2010 00:54:39 +0900 Message-ID: <1271606079.2100.159.camel@barrios-desktop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: Tejun Heo , Mel Gorman , Andrew Morton , KAMEZAWA Hiroyuki , Bob Liu , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Hi, Christoph. On Fri, 2010-04-16 at 11:07 -0500, Christoph Lameter wrote: > On Thu, 15 Apr 2010, Minchan Kim wrote: > > > I don't want to remove alloc_pages for UMA system. > > alloc_pages is the same as alloc_pages_any_node so why have it? I don't want to force using '_node' postfix on UMA users. Maybe they don't care getting page from any node and event don't need to know about _NODE_. > > > #define alloc_pages alloc_page_sexact_node > > > > What I want to remove is just alloc_pages_node. :) > > Why remove it? If you want to get rid of -1 handling then check all the alloc_pages_node have multiple meaning as you said. So some of users misuses that API. I want to clear intention of user. > callsites and make sure that they are not using -1. Sure. I must do it before any progressing. > > Also could you define a constant for -1? -1 may have various meanings. One > is the local node and the other is any node. The difference is if memory > policies are obeyed or not. Note that alloc_pages follows memory policies > whereas alloc_pages_node does not. > > Therefore > > alloc_pages() != alloc_pages_node( , -1) > Yes, now it's totally different. On UMA, It's any node but on NUMA, local node. My concern is following as. alloc_pages_node means any node but it has nid argument. Why should user of alloc_pages who want to get page from any node pass nid argument? It's rather awkward. Some of user misunderstood it and used alloc_pages_node instead of alloc_pages_exact_node although he already know exact _NID_. Of course, it's not a BUG since if nid >= 0 it works well. But I want to remove such multiple meaning to clear intention of user. -- Kind regards, Minchan Kim -- 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