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Commit 2f1b6248 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

[PATCH] reduce MAX_NR_ZONES: use enum to define zones, reformat and comment 



Use enum for zones and reformat zones dependent information

Add comments explaning the use of zones and add a zones_t type for zone
numbers.

Line up information that will be #ifdefd by the following patches.

[akpm@osdl.org: comment cleanups]
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 98d2b0eb

include/linux/mm.h

+4 −3
Original line number Original line Diff line number Diff line
@@ -470,7 +470,7 @@ void split_page(struct page *page, unsigned int order); 
#define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)

#define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)

#define ZONETABLE_MASK		((1UL << ZONETABLE_SHIFT) - 1)

#define ZONETABLE_MASK		((1UL << ZONETABLE_SHIFT) - 1)





static inline unsigned long page_zonenum(struct page *page)

static inline enum zone_type page_zonenum(struct page *page)

{

{

	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;

	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;

}

}
@@ -499,11 +499,12 @@ static inline unsigned long page_to_section(struct page *page) 
	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;

	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;

}

}





static inline void set_page_zone(struct page *page, unsigned long zone)

static inline void set_page_zone(struct page *page, enum zone_type zone)

{

{

	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);

	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);

	page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;

	page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;

}

}



static inline void set_page_node(struct page *page, unsigned long node)

static inline void set_page_node(struct page *page, unsigned long node)

{

{

	page->flags &= ~(NODES_MASK << NODES_PGSHIFT);

	page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
@@ -515,7 +516,7 @@ static inline void set_page_section(struct page *page, unsigned long section) 
	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;

	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;

}

}





static inline void set_page_links(struct page *page, unsigned long zone,

static inline void set_page_links(struct page *page, enum zone_type zone,

	unsigned long node, unsigned long pfn)

	unsigned long node, unsigned long pfn)

{

{

	set_page_zone(page, zone);

	set_page_zone(page, zone);

include/linux/mmzone.h

+47 −19
Original line number Original line Diff line number Diff line
@@ -88,14 +88,53 @@ struct per_cpu_pageset { 
#define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])

#define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])

#endif

#endif





#define ZONE_DMA		0

enum zone_type {

#define ZONE_DMA32		1

	/*

#define ZONE_NORMAL		2

	 * ZONE_DMA is used when there are devices that are not able

#define ZONE_HIGHMEM		3

	 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we

	 * carve out the portion of memory that is needed for these devices.

	 * The range is arch specific.

	 *

	 * Some examples

	 *

	 * Architecture		Limit

	 * ---------------------------

	 * parisc, ia64, sparc	<4G

	 * s390			<2G

	 * arm26		<48M

	 * arm			Various

	 * alpha		Unlimited or 0-16MB.

	 *

	 * i386, x86_64 and multiple other arches

	 * 			<16M.

	 */

	ZONE_DMA,

	/*

	 * x86_64 needs two ZONE_DMAs because it supports devices that are

	 * only able to do DMA to the lower 16M but also 32 bit devices that

	 * can only do DMA areas below 4G.

	 */

	ZONE_DMA32,

	/*

	 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be

	 * performed on pages in ZONE_NORMAL if the DMA devices support

	 * transfers to all addressable memory.

	 */

	ZONE_NORMAL,

	/*

	 * A memory area that is only addressable by the kernel through

	 * mapping portions into its own address space. This is for example

	 * used by i386 to allow the kernel to address the memory beyond

	 * 900MB. The kernel will set up special mappings (page

	 * table entries on i386) for each page that the kernel needs to

	 * access.

	 */

	ZONE_HIGHMEM,





#define MAX_NR_ZONES		4	/* Sync this with ZONES_SHIFT */

	MAX_NR_ZONES

#define ZONES_SHIFT		2	/* ceil(log2(MAX_NR_ZONES)) */

};





#define	ZONES_SHIFT		2	/* ceil(log2(MAX_NR_ZONES)) */





/*

/*

 * When a memory allocation must conform to specific limitations (such

 * When a memory allocation must conform to specific limitations (such
@@ -126,16 +165,6 @@ struct per_cpu_pageset { 
/* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */

/* #define GFP_ZONETYPES       (GFP_ZONEMASK + 1) */           /* Non-loner */

#define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */

#define GFP_ZONETYPES  ((GFP_ZONEMASK + 1) / 2 + 1)            /* Loner */





/*

 * On machines where it is needed (eg PCs) we divide physical memory

 * into multiple physical zones. On a 32bit PC we have 4 zones:

 *

 * ZONE_DMA	  < 16 MB	ISA DMA capable memory

 * ZONE_DMA32	     0 MB 	Empty

 * ZONE_NORMAL	16-896 MB	direct mapped by the kernel

 * ZONE_HIGHMEM	 > 896 MB	only page cache and user processes

 */



struct zone {

struct zone {

	/* Fields commonly accessed by the page allocator */

	/* Fields commonly accessed by the page allocator */

	unsigned long		free_pages;

	unsigned long		free_pages;
@@ -266,7 +295,6 @@ struct zone { 
	char			*name;

	char			*name;

} ____cacheline_internodealigned_in_smp;

} ____cacheline_internodealigned_in_smp;







/*

/*

 * The "priority" of VM scanning is how much of the queues we will scan in one

 * The "priority" of VM scanning is how much of the queues we will scan in one

 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the

 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
@@ -373,12 +401,12 @@ static inline int populated_zone(struct zone *zone) 
	return (!!zone->present_pages);

	return (!!zone->present_pages);

}

}





static inline int is_highmem_idx(int idx)

static inline int is_highmem_idx(enum zone_type idx)

{

{

	return (idx == ZONE_HIGHMEM);

	return (idx == ZONE_HIGHMEM);

}

}





static inline int is_normal_idx(int idx)

static inline int is_normal_idx(enum zone_type idx)

{

{

	return (idx == ZONE_NORMAL);

	return (idx == ZONE_NORMAL);

}

}

mm/page_alloc.c

+18 −6
Original line number Original line Diff line number Diff line
@@ -68,7 +68,11 @@ static void __free_pages_ok(struct page *page, unsigned int order); 
 * TBD: should special case ZONE_DMA32 machines here - in those we normally

 * TBD: should special case ZONE_DMA32 machines here - in those we normally

 * don't need any ZONE_NORMAL reservation

 * don't need any ZONE_NORMAL reservation

 */

 */

int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 256, 32 };

int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {

	 256,

	 256,

	 32

};





EXPORT_SYMBOL(totalram_pages);

EXPORT_SYMBOL(totalram_pages);
@@ -79,7 +83,13 @@ EXPORT_SYMBOL(totalram_pages); 
struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;

struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;

EXPORT_SYMBOL(zone_table);

EXPORT_SYMBOL(zone_table);





static char *zone_names[MAX_NR_ZONES] = { "DMA", "DMA32", "Normal", "HighMem" };

static char *zone_names[MAX_NR_ZONES] = {

	 "DMA",

	 "DMA32",

	 "Normal",

	 "HighMem"

};



int min_free_kbytes = 1024;

int min_free_kbytes = 1024;





unsigned long __meminitdata nr_kernel_pages;

unsigned long __meminitdata nr_kernel_pages;
@@ -1487,7 +1497,9 @@ static void __meminit build_zonelists(pg_data_t *pgdat) 




static void __meminit build_zonelists(pg_data_t *pgdat)

static void __meminit build_zonelists(pg_data_t *pgdat)

{

{

	int i, j, k, node, local_node;

	int i, node, local_node;

	enum zone_type k;

	enum zone_type j;





	local_node = pgdat->node_id;

	local_node = pgdat->node_id;

	for (i = 0; i < GFP_ZONETYPES; i++) {

	for (i = 0; i < GFP_ZONETYPES; i++) {
@@ -1675,8 +1687,8 @@ void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone, 
}

}





#define ZONETABLE_INDEX(x, zone_nr)	((x << ZONES_SHIFT) | zone_nr)

#define ZONETABLE_INDEX(x, zone_nr)	((x << ZONES_SHIFT) | zone_nr)

void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,

void zonetable_add(struct zone *zone, int nid, enum zone_type zid,

		unsigned long size)

		unsigned long pfn, unsigned long size)

{

{

	unsigned long snum = pfn_to_section_nr(pfn);

	unsigned long snum = pfn_to_section_nr(pfn);

	unsigned long end = pfn_to_section_nr(pfn + size);

	unsigned long end = pfn_to_section_nr(pfn + size);
@@ -1960,7 +1972,7 @@ __meminit int init_currently_empty_zone(struct zone *zone, 
static void __meminit free_area_init_core(struct pglist_data *pgdat,

static void __meminit free_area_init_core(struct pglist_data *pgdat,

		unsigned long *zones_size, unsigned long *zholes_size)

		unsigned long *zones_size, unsigned long *zholes_size)

{

{

	unsigned long j;

	enum zone_type j;

	int nid = pgdat->node_id;

	int nid = pgdat->node_id;

	unsigned long zone_start_pfn = pgdat->node_start_pfn;

	unsigned long zone_start_pfn = pgdat->node_start_pfn;

	int ret;

	int ret;