From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751171AbZH1Ng3 (ORCPT ); Fri, 28 Aug 2009 09:36:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750937AbZH1Ng2 (ORCPT ); Fri, 28 Aug 2009 09:36:28 -0400 Received: from gir.skynet.ie ([193.1.99.77]:33539 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750851AbZH1Ng2 (ORCPT ); Fri, 28 Aug 2009 09:36:28 -0400 Date: Fri, 28 Aug 2009 14:36:31 +0100 From: Mel Gorman To: Pekka Enberg Cc: Andrew Morton , Linux Memory Management List , Christoph Lameter , Nick Piggin , Linux Kernel Mailing List Subject: Re: [PATCH 2/2] page-allocator: Maintain rolling count of pages to free from the PCP Message-ID: <20090828133631.GF5054@csn.ul.ie> References: <1251449067-3109-1-git-send-email-mel@csn.ul.ie> <1251449067-3109-3-git-send-email-mel@csn.ul.ie> <84144f020908280516y6473a531n3f11f3e86251eba4@mail.gmail.com> <20090828125719.GE5054@csn.ul.ie> <1251464564.8514.3.camel@penberg-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1251464564.8514.3.camel@penberg-laptop> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 28, 2009 at 04:02:44PM +0300, Pekka Enberg wrote: > Hi Mel, > > On Fri, 2009-08-28 at 13:57 +0100, Mel Gorman wrote: > > On Fri, Aug 28, 2009 at 03:16:34PM +0300, Pekka Enberg wrote: > > > Hi Mel, > > > > > > On Fri, Aug 28, 2009 at 11:44 AM, Mel Gorman wrote: > > > > - page = list_entry(list->prev, struct page, lru); > > > > - /* have to delete it as __free_one_page list manipulates */ > > > > - list_del(&page->lru); > > > > - trace_mm_page_pcpu_drain(page, 0, migratetype); > > > > - __free_one_page(page, zone, 0, migratetype); > > > > + do { > > > > + page = list_entry(list->prev, struct page, lru); > > > > + /* must delete as __free_one_page list manipulates */ > > > > + list_del(&page->lru); > > > > + __free_one_page(page, zone, 0, migratetype); > > > > + trace_mm_page_pcpu_drain(page, 0, migratetype); > > > > > > This calls trace_mm_page_pcpu_drain() *after* __free_one_page(). It's > > > probably not a good idea as __free_one_page() can alter the struct > > > page in various ways. > > > > > > > While true, does it alter the struct page in any way that matters? > > Page flags and order are probably interesting for tracing? > This is PCPU draining. The flags are already clear of any values of interest and the order is always 0. I can follow up a fix-patch that reverses it just in case but I don't think it makes a major difference? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab