[mirror_ubuntu-bionic-kernel.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 */

/*
 * 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
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
	35	/*
	36	* page->flags layout:
	37	*
75980e97 PZ	38	* There are five possibilities for how page->flags get laid out. The first
	39	* pair is for the normal case without sparsemem. The second pair is for
	40	* sparsemem when there is plenty of space for node and section information.
	41	* The last is when there is insufficient space in page->flags and a separate
	42	* lookup is necessary.
bbeae5b0	43	*
b795854b	44	* No sparsemem or sparsemem vmemmap: \| NODE \| ZONE \| ... \| FLAGS \|
90572890	45	* " plus space for last_cpupid: \| NODE \| ZONE \| LAST_CPUPID ... \| FLAGS \|
b795854b	46	* classic sparse with space for node:\| SECTION \| NODE \| ZONE \| ... \| FLAGS \|
90572890	47	* " plus space for last_cpupid: \| SECTION \| NODE \| ZONE \| LAST_CPUPID ... \| FLAGS \|
bbeae5b0 PZ	48	* classic sparse no space for node: \| SECTION \| ZONE \| ... \| FLAGS \|
	49	*/
	50	#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
	51	#define SECTIONS_WIDTH SECTIONS_SHIFT
	52	#else
	53	#define SECTIONS_WIDTH 0
	54	#endif
	55
	56	#define ZONES_WIDTH ZONES_SHIFT
	57
	58	#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
	59	#define NODES_WIDTH NODES_SHIFT
	60	#else
	61	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	62	#error "Vmemmap: No space for nodes field in page flags"
	63	#endif
	64	#define NODES_WIDTH 0
	65	#endif
	66
75980e97	67	#ifdef CONFIG_NUMA_BALANCING
b795854b MG	68	#define LAST__PID_SHIFT 8
	69	#define LAST__PID_MASK ((1 << LAST__PID_SHIFT)-1)
	70
90572890 PZ	71	#define LAST__CPU_SHIFT NR_CPUS_BITS
90572890 PZ	72	#define LAST__CPU_MASK ((1 << LAST__CPU_SHIFT)-1)
b795854b	73
90572890	74	#define LAST_CPUPID_SHIFT (LAST__PID_SHIFT+LAST__CPU_SHIFT)
75980e97	75	#else
90572890	76	#define LAST_CPUPID_SHIFT 0
75980e97 PZ	77	#endif
75980e97 PZ	78
90572890 PZ	79	#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
90572890 PZ	80	#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT
75980e97	81	#else
90572890	82	#define LAST_CPUPID_WIDTH 0
75980e97 PZ	83	#endif
75980e97 PZ	84
bbeae5b0 PZ	85	/*
	86	* We are going to use the flags for the page to node mapping if its in
	87	* there. This includes the case where there is no node, so it is implicit.
	88	*/
	89	#if !(NODES_WIDTH > 0 \|\| NODES_SHIFT == 0)
	90	#define NODE_NOT_IN_PAGE_FLAGS
	91	#endif
	92
90572890 PZ	93	#if defined(CONFIG_NUMA_BALANCING) && LAST_CPUPID_WIDTH == 0
90572890 PZ	94	#define LAST_CPUPID_NOT_IN_PAGE_FLAGS
75980e97 PZ	95	#endif
75980e97 PZ	96
bbeae5b0	97	#endif /* _LINUX_PAGE_FLAGS_LAYOUT */