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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125/* 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"#endif
#define ZONES_WIDTH ZONES_SHIFT
#ifdef CONFIG_SPARSEMEM#include <asm/sparsemem.h>#define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)#else#define SECTIONS_SHIFT 0#endif
#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
#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_SHIFT \ <= BITS_PER_LONG - NR_PAGEFLAGS#define NODES_WIDTH NODES_SHIFT#elif defined(CONFIG_SPARSEMEM_VMEMMAP)#error "Vmemmap: No space for nodes field in page flags"#else#define NODES_WIDTH 0#endif
/* * Note that this #define MUST have a value so that it can be tested with * the IS_ENABLED() macro. */#if NODES_SHIFT != 0 && NODES_WIDTH == 0#define NODE_NOT_IN_PAGE_FLAGS 1#endif
#if defined(CONFIG_KASAN_SW_TAGS)#define KASAN_TAG_WIDTH 8#elif defined(CONFIG_KASAN_HW_TAGS)#define KASAN_TAG_WIDTH 4#else#define KASAN_TAG_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 ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \ KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS#define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT#else#define LAST_CPUPID_WIDTH 0#endif
#if LAST_CPUPID_SHIFT != 0 && LAST_CPUPID_WIDTH == 0#define LAST_CPUPID_NOT_IN_PAGE_FLAGS#endif
#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \ KASAN_TAG_WIDTH + LAST_CPUPID_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS#error "Not enough bits in page flags"#endif
/* see the comment on MAX_NR_TIERS */#define LRU_REFS_WIDTH min(__LRU_REFS_WIDTH, BITS_PER_LONG - NR_PAGEFLAGS - \ ZONES_WIDTH - LRU_GEN_WIDTH - SECTIONS_WIDTH - \ NODES_WIDTH - KASAN_TAG_WIDTH - LAST_CPUPID_WIDTH)
#define NR_NON_PAGEFLAG_BITS (SECTIONS_WIDTH + NODES_WIDTH + ZONES_WIDTH + \ LAST_CPUPID_SHIFT + KASAN_TAG_WIDTH + \ LRU_GEN_WIDTH + LRU_REFS_WIDTH)
#define NR_UNUSED_PAGEFLAG_BITS (BITS_PER_LONG - \ (NR_NON_PAGEFLAG_BITS + NR_PAGEFLAGS))
#endif#endif /* _LINUX_PAGE_FLAGS_LAYOUT */