[linux-2.6-block.git] / include / linux / page-flags-layout.h

#ifndef PAGE_FLAGS_LAYOUT_H
#define PAGE_FLAGS_LAYOUT_H

#include <linux/numa.h>
#include <generated/bounds.h>

/*
 * When a memory allocation must conform to specific limitations (such
 * as being suitable for DMA) the caller will pass in hints to the
 * allocator in the gfp_mask, in the zone modifier bits.  These bits
 * are used to select a priority ordered list of memory zones which
 * match the requested limits. See gfp_zone() in include/linux/gfp.h
 */
#if MAX_NR_ZONES < 2
#define ZONES_SHIFT 0
#elif MAX_NR_ZONES <= 2
#define ZONES_SHIFT 1
#elif MAX_NR_ZONES <= 4
#define ZONES_SHIFT 2
#else
#error ZONES_SHIFT -- too many zones configured adjust calculation
#endif

#ifdef CONFIG_SPARSEMEM
#include <asm/sparsemem.h>

/* SECTION_SHIFT	#bits space required to store a section # */
#define SECTIONS_SHIFT	(MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)

#endif /* CONFIG_SPARSEMEM */

/*
 * page->flags layout:
 *
 * There are five possibilities for how page->flags get laid out.  The first
 * pair is for the normal case without sparsemem. The second pair is for
 * sparsemem when there is plenty of space for node and section information.
 * The last is when there is insufficient space in page->flags and a separate
 * lookup is necessary.
 *
 * No sparsemem or sparsemem vmemmap: |       NODE     | ZONE |             ... | FLAGS |
 *      " plus space for last_cpupid: |       NODE     | ZONE | LAST_CPUPID ... | FLAGS |
 * classic sparse with space for node:| SECTION | NODE | ZONE |             ... | FLAGS |
 *      " plus space for last_cpupid: | SECTION | NODE | ZONE | LAST_CPUPID ... | FLAGS |
 * classic sparse no space for node:  | SECTION |     ZONE    | ... | FLAGS |
 */
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define SECTIONS_WIDTH		SECTIONS_SHIFT
#else
#define SECTIONS_WIDTH		0
#endif

#define ZONES_WIDTH		ZONES_SHIFT

#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
#define NODES_WIDTH		NODES_SHIFT
#else
#ifdef CONFIG_SPARSEMEM_VMEMMAP
#error "Vmemmap: No space for nodes field in page flags"
#endif
#define NODES_WIDTH		0
#endif

#ifdef CONFIG_NUMA_BALANCING
#define LAST__PID_SHIFT 8
#define LAST__PID_MASK  ((1 << LAST__PID_SHIFT)-1)

#define LAST__CPU_SHIFT NR_CPUS_BITS
#define LAST__CPU_MASK  ((1 << LAST__CPU_SHIFT)-1)

#define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT)
#else
#define LAST_CPUPID_SHIFT 0
#endif

#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
#else
#define LAST_CPUPID_WIDTH 0
#endif

/*
 * We are going to use the flags for the page to node mapping if its in
 * there.  This includes the case where there is no node, so it is implicit.
 */
#if !(NODES_WIDTH > 0 || NODES_SHIFT == 0)
#define NODE_NOT_IN_PAGE_FLAGS
#endif

#if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0
#define LAST_CPUPID_NOT_IN_PAGE_FLAGS
#endif

#endif /* _LINUX_PAGE_FLAGS_LAYOUT */
Commit	Line	Data
bbeae5b0 PZ	1	#ifndef PAGE_FLAGS_LAYOUT_H
	2	#define PAGE_FLAGS_LAYOUT_H
	3
	4	#include <linux/numa.h>
	5	#include <generated/bounds.h>
	6
	7	/*
	8	* When a memory allocation must conform to specific limitations (such
	9	* as being suitable for DMA) the caller will pass in hints to the
	10	* allocator in the gfp_mask, in the zone modifier bits. These bits
	11	* are used to select a priority ordered list of memory zones which
	12	* match the requested limits. See gfp_zone() in include/linux/gfp.h
	13	*/
	14	#if MAX_NR_ZONES < 2
	15	#define ZONES_SHIFT 0
	16	#elif MAX_NR_ZONES <= 2
	17	#define ZONES_SHIFT 1
	18	#elif MAX_NR_ZONES <= 4
	19	#define ZONES_SHIFT 2
	20	#else
	21	#error ZONES_SHIFT -- too many zones configured adjust calculation
	22	#endif
	23
	24	#ifdef CONFIG_SPARSEMEM
	25	#include <asm/sparsemem.h>
	26
	27	/* SECTION_SHIFT #bits space required to store a section # */
	28	#define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
	29
	30	#endif /* CONFIG_SPARSEMEM */
	31
	32	/*
	33	* page->flags layout:
	34	*
75980e97 PZ	35	* There are five possibilities for how page->flags get laid out. The first
	36	* pair is for the normal case without sparsemem. The second pair is for
	37	* sparsemem when there is plenty of space for node and section information.
	38	* The last is when there is insufficient space in page->flags and a separate
	39	* lookup is necessary.
bbeae5b0	40	*
b795854b	41	* No sparsemem or sparsemem vmemmap: \| NODE \| ZONE \| ... \| FLAGS \|
90572890	42	* " plus space for last_cpupid: \| NODE \| ZONE \| LAST_CPUPID ... \| FLAGS \|
b795854b	43	* classic sparse with space for node:\| SECTION \| NODE \| ZONE \| ... \| FLAGS \|
90572890	44	* " plus space for last_cpupid: \| SECTION \| NODE \| ZONE \| LAST_CPUPID ... \| FLAGS \|
bbeae5b0 PZ	45	* classic sparse no space for node: \| SECTION \| ZONE \| ... \| FLAGS \|
	46	*/
	47	#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
	48	#define SECTIONS_WIDTH SECTIONS_SHIFT
	49	#else
	50	#define SECTIONS_WIDTH 0
	51	#endif
	52
	53	#define ZONES_WIDTH ZONES_SHIFT
	54
	55	#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
	56	#define NODES_WIDTH NODES_SHIFT
	57	#else
	58	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	59	#error "Vmemmap: No space for nodes field in page flags"
	60	#endif
	61	#define NODES_WIDTH 0
	62	#endif
	63
75980e97	64	#ifdef CONFIG_NUMA_BALANCING
b795854b MG	65	#define LAST__PID_SHIFT 8
	66	#define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1)
	67
90572890 PZ	68	#define LAST__CPU_SHIFT NR_CPUS_BITS
90572890 PZ	69	#define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1)
b795854b	70
90572890	71	#define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT)
75980e97	72	#else
90572890	73	#define LAST_CPUPID_SHIFT 0
75980e97 PZ	74	#endif
75980e97 PZ	75
90572890 PZ	76	#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
90572890 PZ	77	#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
75980e97	78	#else
90572890	79	#define LAST_CPUPID_WIDTH 0
75980e97 PZ	80	#endif
75980e97 PZ	81
bbeae5b0 PZ	82	/*
	83	* We are going to use the flags for the page to node mapping if its in
	84	* there. This includes the case where there is no node, so it is implicit.
	85	*/
	86	#if !(NODES_WIDTH > 0 \|\| NODES_SHIFT == 0)
	87	#define NODE_NOT_IN_PAGE_FLAGS
	88	#endif
	89
90572890 PZ	90	#if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0
90572890 PZ	91	#define LAST_CPUPID_NOT_IN_PAGE_FLAGS
75980e97 PZ	92	#endif
75980e97 PZ	93
bbeae5b0	94	#endif /* _LINUX_PAGE_FLAGS_LAYOUT */