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

/* SPDX-License-Identifier: GPL-2.0 */
#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
#elif MAX_NR_ZONES <= 8
#define ZONES_SHIFT 3
#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 */

#ifndef BUILD_VDSO32_64
/*
 * 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

#ifdef CONFIG_KASAN_SW_TAGS
#define KASAN_TAG_WIDTH 8
#else
#define KASAN_TAG_WIDTH 0
#endif

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

#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \
	> BITS_PER_LONG - NR_PAGEFLAGS
#error "Not enough bits in page flags"
#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
#endif /* _LINUX_PAGE_FLAGS_LAYOUT */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
bbeae5b0 PZ	2	#ifndef PAGE_FLAGS_LAYOUT_H
	3	#define PAGE_FLAGS_LAYOUT_H
	4
	5	#include <linux/numa.h>
	6	#include <generated/bounds.h>
	7
	8	/*
	9	* When a memory allocation must conform to specific limitations (such
	10	* as being suitable for DMA) the caller will pass in hints to the
	11	* allocator in the gfp_mask, in the zone modifier bits. These bits
	12	* are used to select a priority ordered list of memory zones which
	13	* match the requested limits. See gfp_zone() in include/linux/gfp.h
	14	*/
	15	#if MAX_NR_ZONES < 2
	16	#define ZONES_SHIFT 0
	17	#elif MAX_NR_ZONES <= 2
	18	#define ZONES_SHIFT 1
	19	#elif MAX_NR_ZONES <= 4
	20	#define ZONES_SHIFT 2
b11a7b94 DW	21	#elif MAX_NR_ZONES <= 8
b11a7b94 DW	22	#define ZONES_SHIFT 3
bbeae5b0 PZ	23	#else
	24	#error ZONES_SHIFT -- too many zones configured adjust calculation
	25	#endif
	26
	27	#ifdef CONFIG_SPARSEMEM
	28	#include <asm/sparsemem.h>
	29
	30	/* SECTION_SHIFT #bits space required to store a section # */
	31	#define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
	32
	33	#endif /* CONFIG_SPARSEMEM */
	34
ee38d94a	35	#ifndef BUILD_VDSO32_64
bbeae5b0 PZ	36	/*
	37	* page->flags layout:
	38	*
75980e97 PZ	39	* There are five possibilities for how page->flags get laid out. The first
	40	* pair is for the normal case without sparsemem. The second pair is for
	41	* sparsemem when there is plenty of space for node and section information.
	42	* The last is when there is insufficient space in page->flags and a separate
	43	* lookup is necessary.
bbeae5b0	44	*
b795854b	45	* No sparsemem or sparsemem vmemmap: \| NODE \| ZONE \| ... \| FLAGS \|
90572890	46	* " plus space for last_cpupid: \| NODE \| ZONE \| LAST_CPUPID ... \| FLAGS \|
b795854b	47	* classic sparse with space for node:\| SECTION \| NODE \| ZONE \| ... \| FLAGS \|
90572890	48	* " plus space for last_cpupid: \| SECTION \| NODE \| ZONE \| LAST_CPUPID ... \| FLAGS \|
bbeae5b0 PZ	49	* classic sparse no space for node: \| SECTION \| ZONE \| ... \| FLAGS \|
	50	*/
	51	#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
	52	#define SECTIONS_WIDTH SECTIONS_SHIFT
	53	#else
	54	#define SECTIONS_WIDTH 0
	55	#endif
	56
	57	#define ZONES_WIDTH ZONES_SHIFT
	58
	59	#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
	60	#define NODES_WIDTH NODES_SHIFT
	61	#else
	62	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	63	#error "Vmemmap: No space for nodes field in page flags"
	64	#endif
	65	#define NODES_WIDTH 0
	66	#endif
	67
75980e97	68	#ifdef CONFIG_NUMA_BALANCING
b795854b MG	69	#define LAST__PID_SHIFT 8
	70	#define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1)
	71
90572890 PZ	72	#define LAST__CPU_SHIFT NR_CPUS_BITS
90572890 PZ	73	#define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1)
b795854b	74
90572890	75	#define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT)
75980e97	76	#else
90572890	77	#define LAST_CPUPID_SHIFT 0
75980e97 PZ	78	#endif
75980e97 PZ	79
ee38d94a AB	80	#ifdef CONFIG_KASAN_SW_TAGS
	81	#define KASAN_TAG_WIDTH 8
	82	#else
	83	#define KASAN_TAG_WIDTH 0
	84	#endif
	85
	86	#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT+KASAN_TAG_WIDTH \
	87	<= BITS_PER_LONG - NR_PAGEFLAGS
90572890	88	#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
75980e97	89	#else
90572890	90	#define LAST_CPUPID_WIDTH 0
75980e97 PZ	91	#endif
75980e97 PZ	92
2813b9c0 AK	93	#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \
2813b9c0 AK	94	> BITS_PER_LONG - NR_PAGEFLAGS
ee38d94a	95	#error "Not enough bits in page flags"
2813b9c0 AK	96	#endif
2813b9c0 AK	97
bbeae5b0 PZ	98	/*
	99	* We are going to use the flags for the page to node mapping if its in
	100	* there. This includes the case where there is no node, so it is implicit.
	101	*/
	102	#if !(NODES_WIDTH > 0 \|\| NODES_SHIFT == 0)
	103	#define NODE_NOT_IN_PAGE_FLAGS
	104	#endif
	105
90572890 PZ	106	#if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0
90572890 PZ	107	#define LAST_CPUPID_NOT_IN_PAGE_FLAGS
75980e97 PZ	108	#endif
75980e97 PZ	109
ee38d94a	110	#endif
bbeae5b0	111	#endif /* _LINUX_PAGE_FLAGS_LAYOUT */