From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932385AbWAWJkx (ORCPT ); Mon, 23 Jan 2006 04:40:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932419AbWAWJkx (ORCPT ); Mon, 23 Jan 2006 04:40:53 -0500 Received: from holly.csn.ul.ie ([136.201.105.4]:58512 "EHLO holly.csn.ul.ie") by vger.kernel.org with ESMTP id S932385AbWAWJkx (ORCPT ); Mon, 23 Jan 2006 04:40:53 -0500 Date: Mon, 23 Jan 2006 09:39:16 +0000 (GMT) From: Mel Gorman X-X-Sender: mel@skynet To: Marcelo Tosatti Cc: linux-mm@kvack.org, jschopp@austin.ibm.com, linux-kernel@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, lhms-devel@lists.sourceforge.net Subject: Re: [PATCH 2/4] Split the free lists into kernel and user parts In-Reply-To: <20060122133147.GA4186@dmt.cnet> Message-ID: References: <20060120115415.16475.8529.sendpatchset@skynet.csn.ul.ie> <20060120115455.16475.93688.sendpatchset@skynet.csn.ul.ie> <20060122133147.GA4186@dmt.cnet> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 22 Jan 2006, Marcelo Tosatti wrote: > Hi Mel, > > On Fri, Jan 20, 2006 at 11:54:55AM +0000, Mel Gorman wrote: > > > > This patch adds the core of the anti-fragmentation strategy. It works by > > grouping related allocation types together. The idea is that large groups of > > pages that may be reclaimed are placed near each other. The zone->free_area > > list is broken into RCLM_TYPES number of lists. > > > > Signed-off-by: Mel Gorman > > Signed-off-by: Joel Schopp > > diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc1-mm1-001_antifrag_flags/include/linux/mmzone.h linux-2.6.16-rc1-mm1-002_fragcore/include/linux/mmzone.h > > --- linux-2.6.16-rc1-mm1-001_antifrag_flags/include/linux/mmzone.h 2006-01-19 11:21:59.000000000 +0000 > > +++ linux-2.6.16-rc1-mm1-002_fragcore/include/linux/mmzone.h 2006-01-19 21:51:05.000000000 +0000 > > @@ -22,8 +22,16 @@ > > #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER > > #endif > > > > +#define RCLM_NORCLM 0 > > +#define RCLM_EASY 1 > > +#define RCLM_TYPES 2 > > + > > +#define for_each_rclmtype_order(type, order) \ > > + for (order = 0; order < MAX_ORDER; order++) \ > > + for (type = 0; type < RCLM_TYPES; type++) > > + > > struct free_area { > > - struct list_head free_list; > > + struct list_head free_list[RCLM_TYPES]; > > unsigned long nr_free; > > }; > > > > diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc1-mm1-001_antifrag_flags/include/linux/page-flags.h linux-2.6.16-rc1-mm1-002_fragcore/include/linux/page-flags.h > > --- linux-2.6.16-rc1-mm1-001_antifrag_flags/include/linux/page-flags.h 2006-01-19 11:21:59.000000000 +0000 > > +++ linux-2.6.16-rc1-mm1-002_fragcore/include/linux/page-flags.h 2006-01-19 21:51:05.000000000 +0000 > > @@ -76,6 +76,7 @@ > > #define PG_reclaim 17 /* To be reclaimed asap */ > > #define PG_nosave_free 18 /* Free, should not be written */ > > #define PG_uncached 19 /* Page has been mapped as uncached */ > > +#define PG_easyrclm 20 /* Page is in an easy reclaim block */ > > > > /* > > * Global page accounting. One instance per CPU. Only unsigned longs are > > @@ -345,6 +346,12 @@ extern void __mod_page_state_offset(unsi > > #define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags) > > #define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags) > > > > +#define PageEasyRclm(page) test_bit(PG_easyrclm, &(page)->flags) > > +#define SetPageEasyRclm(page) set_bit(PG_easyrclm, &(page)->flags) > > +#define ClearPageEasyRclm(page) clear_bit(PG_easyrclm, &(page)->flags) > > +#define __SetPageEasyRclm(page) __set_bit(PG_easyrclm, &(page)->flags) > > +#define __ClearPageEasyRclm(page) __clear_bit(PG_easyrclm, &(page)->flags) > > + > > You can't read/write to page->flags non-atomically, except when you > guarantee that the page is not visible to other CPU's (eg at the very > end of the page freeing code). > The helper PageEasyRclm is only used when either the spinlock is held or a per-cpu page is being released so it should be safe. The Set and Clear helpers are only used with a spinlock held. > Please use atomic operations. > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab