Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761236AbYCAEKi (ORCPT ); Fri, 29 Feb 2008 23:10:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758378AbYCAEGz (ORCPT ); Fri, 29 Feb 2008 23:06:55 -0500 Received: from relay1.sgi.com ([192.48.171.29]:46590 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751757AbYCAEGY (ORCPT ); Fri, 29 Feb 2008 23:06:24 -0500 Message-Id: <20080301040621.484085808@sgi.com> References: <20080301040534.797979115@sgi.com> User-Agent: quilt/0.46-1 Date: Fri, 29 Feb 2008 20:05:41 -0800 From: Christoph Lameter To: linux-kernel@vger.kernel.org Cc: Mel Gorman Cc: Nick Piggin Cc: Rik van Riel Cc: Andrew Morton Cc: apw@shadowen.org Cc: linux-mm@kback.org Subject: [rfc 07/10] Pageflags: Get rid of FLAGS_RESERVED Content-Disposition: inline; filename=pageflags-get-rid-of-flags-reserved Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5169 Lines: 149 NR_PAGEFLAGS specifies the number of page flags we are using. >From that we can calculate the number of bits leftover that can be used for zone, node (and maybe the sections id). There is no need anymore for FLAGS_RESERVED if we use NR_PAGEFLAGS. Use the new methods to make NR_PAGEFLAGS available via the preprocessor. NR_PAGEFLAGS is used to calculate field boundaries in the page flags fields. These field widths have to be available to the preprocessor. Signed-off-by: Christoph Lameter --- include/linux/bounds.h | 2 ++ include/linux/mm.h | 6 +++--- include/linux/mmzone.h | 19 ------------------- include/linux/page-flags.h | 14 +++++++------- kernel/bounds.c | 1 + 5 files changed, 13 insertions(+), 29 deletions(-) Index: linux-2.6/include/linux/mm.h =================================================================== --- linux-2.6.orig/include/linux/mm.h 2008-02-29 19:21:35.000000000 -0800 +++ linux-2.6/include/linux/mm.h 2008-02-29 19:29:53.000000000 -0800 @@ -402,7 +402,7 @@ static inline void set_compound_order(st #define ZONES_WIDTH ZONES_SHIFT -#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= FLAGS_RESERVED +#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS #define NODES_WIDTH NODES_SHIFT #else #define NODES_WIDTH 0 @@ -447,8 +447,8 @@ static inline void set_compound_order(st #define ZONEID_PGSHIFT (ZONEID_PGOFF * (ZONEID_SHIFT != 0)) -#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED -#error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED +#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS +#error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS #endif #define ZONES_MASK ((1UL << ZONES_WIDTH) - 1) Index: linux-2.6/include/linux/mmzone.h =================================================================== --- linux-2.6.orig/include/linux/mmzone.h 2008-02-29 19:13:55.000000000 -0800 +++ linux-2.6/include/linux/mmzone.h 2008-02-29 19:29:53.000000000 -0800 @@ -735,25 +735,6 @@ extern struct zone *next_zone(struct zon #include #endif -#if BITS_PER_LONG == 32 -/* - * with 32 bit page->flags field, we reserve 9 bits for node/zone info. - * there are 4 zones (3 bits) and this leaves 9-3=6 bits for nodes. - */ -#define FLAGS_RESERVED 9 - -#elif BITS_PER_LONG == 64 -/* - * with 64 bit flags field, there's plenty of room. - */ -#define FLAGS_RESERVED 32 - -#else - -#error BITS_PER_LONG not defined - -#endif - #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \ !defined(CONFIG_ARCH_POPULATES_NODE_MAP) #define early_pfn_to_nid(nid) (0UL) Index: linux-2.6/include/linux/page-flags.h =================================================================== --- linux-2.6.orig/include/linux/page-flags.h 2008-02-29 19:20:11.000000000 -0800 +++ linux-2.6/include/linux/page-flags.h 2008-02-29 19:29:53.000000000 -0800 @@ -7,6 +7,7 @@ #include #include +#include /* * Various page->flags bits: @@ -59,13 +60,12 @@ * extends from the high bits downwards. * * | FIELD | ... | FLAGS | - * N-1 ^ 0 - * (N-FLAGS_RESERVED) + * N-1 ^ 0 + * (NR_PAGEFLAGS) * - * The fields area is reserved for fields mapping zone, node and SPARSEMEM - * section. The boundry between these two areas is defined by - * FLAGS_RESERVED which defines the width of the fields section - * (see linux/mmzone.h). New flags must _not_ overlap with this area. + * The fields area is reserved for fields mapping zone, node (for NUMA) and + * SPARSEMEM section (for variants of SPARSEMEM that require section ids like + * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). */ enum pageflags { PG_locked, /* Page is locked. Don't touch. */ @@ -86,7 +86,6 @@ enum pageflags { PG_mappedtodisk, /* Has blocks allocated on-disk */ PG_reclaim, /* To be reclaimed asap */ PG_buddy, /* Page is free, on buddy lists */ - NR_PAGEFLAGS, /* For verification purposes */ #if (BITS_PER_LONG > 32) /* @@ -98,6 +97,7 @@ enum pageflags { */ PG_uncached = 31, /* Page has been mapped as uncached */ #endif + __NR_PAGEFLAGS, }; /* Index: linux-2.6/kernel/bounds.c =================================================================== --- linux-2.6.orig/kernel/bounds.c 2008-02-29 19:29:38.000000000 -0800 +++ linux-2.6/kernel/bounds.c 2008-02-29 19:29:53.000000000 -0800 @@ -13,4 +13,5 @@ void foo(void) { + DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS); } Index: linux-2.6/include/linux/bounds.h =================================================================== --- linux-2.6.orig/include/linux/bounds.h 2008-02-29 19:30:04.000000000 -0800 +++ linux-2.6/include/linux/bounds.h 2008-02-29 19:30:08.000000000 -0800 @@ -7,4 +7,6 @@ * */ +#define NR_PAGEFLAGS 32 /* __NR_PAGEFLAGS # */ + #endif -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/