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Commit e53ef38d authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

[PATCH] reduce MAX_NR_ZONES: make ZONE_HIGHMEM optional 



Make ZONE_HIGHMEM optional

- ifdef out code and definitions related to CONFIG_HIGHMEM

- __GFP_HIGHMEM falls back to normal allocations if there is no
  ZONE_HIGHMEM

- GFP_ZONEMASK becomes 0x01 if there is no DMA32 and no HIGHMEM
  zone.

[jdike@addtoit.com: build fix]
Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
Signed-off-by: default avatarChristoph Lameter <clameter@engr.sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fb0e7942

arch/um/kernel/mem.c

+2 −0
Original line number Diff line number Diff line
@@ -226,7 +226,9 @@ void paging_init(void) 
	for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++) 

		zones_size[i] = 0;

	zones_size[ZONE_DMA] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);

#ifdef CONFIG_HIGHMEM

	zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;

#endif

	free_area_init(zones_size);



	/*

include/linux/gfp.h

+10 −8
Original line number Diff line number Diff line
@@ -9,17 +9,19 @@ struct vm_area_struct; 


/*

 * GFP bitmasks..

 *

 * Zone modifiers (see linux/mmzone.h - low three bits)

 *

 * These may be masked by GFP_ZONEMASK to make allocations with this bit

 * set fall back to ZONE_NORMAL.

 *

 * Do not put any conditional on these. If necessary modify the definitions

 * without the underscores and use the consistently. The definitions here may

 * be used in bit comparisons.

 */

/* Zone modifiers in GFP_ZONEMASK (see linux/mmzone.h - low three bits) */

#define __GFP_DMA	((__force gfp_t)0x01u)

#define __GFP_HIGHMEM	((__force gfp_t)0x02u)

#ifndef CONFIG_ZONE_DMA32

#define __GFP_DMA32	((__force gfp_t)0x01)	/* ZONE_DMA is ZONE_DMA32 */

#elif BITS_PER_LONG < 64

#define __GFP_DMA32	((__force gfp_t)0x00)	/* ZONE_NORMAL is ZONE_DMA32 */

#else

#define __GFP_DMA32	((__force gfp_t)0x04)	/* Has own ZONE_DMA32 */

#endif

#define __GFP_DMA32	((__force gfp_t)0x04u)



/*

 * Action modifiers - doesn't change the zoning

include/linux/mmzone.h

+33 −3
Original line number Diff line number Diff line
@@ -123,6 +123,7 @@ enum zone_type { 
	 * transfers to all addressable memory.

	 */

	ZONE_NORMAL,

#ifdef CONFIG_HIGHMEM

	/*

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

	 * mapping portions into its own address space. This is for example
@@ -132,11 +133,10 @@ enum zone_type { 
	 * access.

	 */

	ZONE_HIGHMEM,



#endif

	MAX_NR_ZONES

};



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



/*

 * When a memory allocation must conform to specific limitations (such
@@ -163,12 +163,34 @@ enum zone_type { 
 *

 * NOTE! Make sure this matches the zones in <linux/gfp.h>

 */

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



#ifdef CONFIG_ZONE_DMA32



#ifdef CONFIG_HIGHMEM

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

#define GFP_ZONEMASK		0x07

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

#else

#define GFP_ZONETYPES		((0x07 + 1) / 2 + 1)    /* Loner */

/* Mask __GFP_HIGHMEM */

#define GFP_ZONEMASK		0x05

#define ZONES_SHIFT		2

#endif



#else

#ifdef CONFIG_HIGHMEM



#define GFP_ZONEMASK		0x03

#define ZONES_SHIFT		2

#define GFP_ZONETYPES		3



#else



#define GFP_ZONEMASK		0x01

#define ZONES_SHIFT		1

#define GFP_ZONETYPES		2



#endif

#endif



struct zone {
@@ -409,7 +431,11 @@ static inline int populated_zone(struct zone *zone) 


static inline int is_highmem_idx(enum zone_type idx)

{

#ifdef CONFIG_HIGHMEM

	return (idx == ZONE_HIGHMEM);

#else

	return 0;

#endif

}



static inline int is_normal_idx(enum zone_type idx)
@@ -425,7 +451,11 @@ static inline int is_normal_idx(enum zone_type idx) 
 */

static inline int is_highmem(struct zone *zone)

{

#ifdef CONFIG_HIGHMEM

	return zone == zone->zone_pgdat->node_zones + ZONE_HIGHMEM;

#else

	return 0;

#endif

}



static inline int is_normal(struct zone *zone)

mm/page_alloc.c

+6 −0
Original line number Diff line number Diff line
@@ -73,7 +73,9 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 
#ifdef CONFIG_ZONE_DMA32

	 256,

#endif

#ifdef CONFIG_HIGHMEM

	 32

#endif

};



EXPORT_SYMBOL(totalram_pages);
@@ -91,7 +93,9 @@ static char *zone_names[MAX_NR_ZONES] = { 
	 "DMA32",

#endif

	 "Normal",

#ifdef CONFIG_HIGHMEM

	 "HighMem"

#endif

};



int min_free_kbytes = 1024;
@@ -1375,8 +1379,10 @@ static int __meminit build_zonelists_node(pg_data_t *pgdat, 
static inline int highest_zone(int zone_bits)

{

	int res = ZONE_NORMAL;

#ifdef CONFIG_HIGHMEM

	if (zone_bits & (__force int)__GFP_HIGHMEM)

		res = ZONE_HIGHMEM;

#endif

#ifdef CONFIG_ZONE_DMA32

	if (zone_bits & (__force int)__GFP_DMA32)

		res = ZONE_DMA32;