From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 3171F6B0082 for ; Mon, 23 Feb 2009 04:13:27 -0500 (EST) Subject: Re: [PATCH 07/20] Simplify the check on whether cpusets are a factor or not From: Pekka Enberg In-Reply-To: <1235380072.4645.0.camel@laptop> References: <1235344649-18265-1-git-send-email-mel@csn.ul.ie> <1235344649-18265-8-git-send-email-mel@csn.ul.ie> <1235380072.4645.0.camel@laptop> Date: Mon, 23 Feb 2009 11:13:23 +0200 Message-Id: <1235380403.6216.16.camel@penberg-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Mel Gorman , Linux Memory Management List , Rik van Riel , KOSAKI Motohiro , Christoph Lameter , Johannes Weiner , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin List-ID: On Mon, 2009-02-23 at 10:07 +0100, Peter Zijlstra wrote: > On Mon, 2009-02-23 at 09:14 +0200, Pekka J Enberg wrote: > > On Sun, 22 Feb 2009, Mel Gorman wrote: > > > The check whether cpuset contraints need to be checked or not is complex > > > and often repeated. This patch makes the check in advance to the comparison > > > is simplier to compute. > > > > > > Signed-off-by: Mel Gorman > > > > You can do that in a cleaner way by defining ALLOC_CPUSET to be zero when > > CONFIG_CPUSETS is disabled. Something like following untested patch: > > > > Signed-off-by: Pekka Enberg > > --- > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 5675b30..18b687d 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -1135,7 +1135,12 @@ failed: > > #define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */ > > #define ALLOC_HARDER 0x10 /* try to alloc harder */ > > #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */ > > + > > +#ifdef CONFIG_CPUSETS > > #define ALLOC_CPUSET 0x40 /* check for correct cpuset */ > > +#else > > +#define ALLOC_CPUSET 0x00 > > +#endif > > > > Mel's patch however even avoids the code when cpusets are configured but > not actively used (the most common case for distro kernels). Right. Combining both patches is probably the best solution then as we get rid of the #ifdef in get_page_from_freelist(). Pekka -- 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