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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* internal.h: mm/ internal definitions
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (
#ifndef __MM_INTERNAL_H
#define __MM_INTERNAL_H
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/tracepoint-defs.h>
* The set of flags that only affect watermark checking and reclaim
* behaviour. This is used by the MM to obey the caller constraints
* about IO, FS and watermark checking while ignoring placement
* hints such as HIGHMEM usage.
/* The GFP flags allowed during early boot */
/* Control allocation cpuset and node placement constraints */
/* Do not use these with a slab allocator */
void page_writeback_init(void);
vm_fault_t do_swap_page(struct vm_fault *vmf);
void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
unsigned long floor, unsigned long ceiling);
static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
return !(vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP));
void unmap_page_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end,
struct zap_details *details);
extern unsigned int __do_page_cache_readahead(struct address_space *mapping,
struct file *filp, pgoff_t offset, unsigned long nr_to_read,
unsigned long lookahead_size);
* Submit IO for the read-ahead request in file_ra_state.
static inline unsigned long ra_submit(struct file_ra_state *ra,
struct address_space *mapping, struct file *filp)
return __do_page_cache_readahead(mapping, filp,
ra->start, ra->size, ra->async_size);
* page_evictable - test whether a page is evictable
* @page: the page to test
* Test whether page is evictable--i.e., should be placed on active/inactive
* lists vs unevictable list.
* Reasons page might not be evictable:
* (1) page's mapping marked unevictable
* (2) page is part of an mlocked VMA
static inline bool page_evictable(struct page *page)
bool ret;
/* Prevent address_space of inode and swap cache from being freed */
ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
return ret;
* Turn a non-refcounted page (->_refcount == 0) into refcounted with
* a count of one.
static inline void set_page_refcounted(struct page *page)
VM_BUG_ON_PAGE(PageTail(page), page);
VM_BUG_ON_PAGE(page_ref_count(page), page);
set_page_count(page, 1);
extern unsigned long highest_memmap_pfn;
* Maximum number of reclaim retries without progress before the OOM
* killer is consider the only way forward.
* in mm/vmscan.c:
extern int isolate_lru_page(struct page *page);
extern void putback_lru_page(struct page *page);
* in mm/rmap.c:
extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
* in mm/page_alloc.c
* Structure for holding the mostly immutable allocation parameters passed
* between functions involved in allocations, including the alloc_pages*
* family of functions.
* nodemask, migratetype and high_zoneidx are initialized only once in
* __alloc_pages_nodemask() and then never change.
* zonelist, preferred_zone and classzone_idx are set first in
* __alloc_pages_nodemask() for the fast path, and might be later changed
* in __alloc_pages_slowpath(). All other functions pass the whole strucure
* by a const pointer.
struct alloc_context {
struct zonelist *zonelist;
nodemask_t *nodemask;
struct zoneref *preferred_zoneref;
int migratetype;
enum zone_type high_zoneidx;
bool spread_dirty_pages;
#define ac_classzone_idx(ac) zonelist_zone_idx(ac->preferred_zoneref)
* Locate the struct page for both the matching buddy in our
* pair (buddy1) and the combined O(n+1) page they form (page).
* 1) Any buddy B1 will have an order O twin B2 which satisfies
* the following equation:
* B2 = B1 ^ (1 << O)
* For example, if the starting buddy (buddy2) is #8 its order
* 1 buddy is #10:
* B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
* 2) Any buddy B will have an order O+1 parent P which
* satisfies the following equation:
* P = B & ~(1 << O)
* Assumption: *_mem_map is contiguous at least up to MAX_ORDER
static inline unsigned long
__find_buddy_pfn(unsigned long page_pfn, unsigned int order)
return page_pfn ^ (1 << order);
extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
unsigned long end_pfn, struct zone *zone);
static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
unsigned long end_pfn, struct zone *zone)
if (zone->contiguous)
return pfn_to_page(start_pfn);
return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
extern int __isolate_free_page(struct page *page, unsigned int order);
extern void __putback_isolated_page(struct page *page, unsigned int order,
int mt);
extern void memblock_free_pages(struct page *page, unsigned long pfn,
unsigned int order);
extern void __free_pages_core(struct page *page, unsigned int order);
extern void prep_compound_page(struct page *page, unsigned int order);
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
extern int user_min_free_kbytes;
extern void zone_pcp_update(struct zone *zone);
extern void zone_pcp_reset(struct zone *zone);
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
* in mm/compaction.c
* compact_control is used to track pages being migrated and the free pages
* they are being migrated to during memory compaction. The free_pfn starts
* at the end of a zone and migrate_pfn begins at the start. Movable pages
* are moved to the end of a zone during a compaction run and the run
* completes when free_pfn <= migrate_pfn
struct compact_control {
struct list_head freepages; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
unsigned int nr_freepages; /* Number of isolated free pages */
unsigned int nr_migratepages; /* Number of pages to migrate */
unsigned long free_pfn; /* isolate_freepages search base */
unsigned long migrate_pfn; /* isolate_migratepages search base */
unsigned long fast_start_pfn; /* a pfn to start linear scan from */
struct zone *zone;
unsigned long total_migrate_scanned;
unsigned long total_free_scanned;
unsigned short fast_search_fail;/* failures to use free list searches */
short search_order; /* order to start a fast search at */
const gfp_t gfp_mask; /* gfp mask of a direct compactor */
int order; /* order a direct compactor needs */
int migratetype; /* migratetype of direct compactor */
const unsigned int alloc_flags; /* alloc flags of a direct compactor */
const int classzone_idx; /* zone index of a direct compactor */
enum migrate_mode mode; /* Async or sync migration mode */
bool ignore_skip_hint; /* Scan blocks even if marked skip */
bool no_set_skip_hint; /* Don't mark blocks for skipping */
bool ignore_block_suitable; /* Scan blocks considered unsuitable */
bool direct_compaction; /* False from kcompactd or /proc/... */
bool whole_zone; /* Whole zone should/has been scanned */
bool contended; /* Signal lock or sched contention */
bool rescan; /* Rescanning the same pageblock */
bool alloc_contig; /* alloc_contig_range allocation */
* Used in direct compaction when a page should be taken from the freelists
* immediately when one is created during the free path.
struct capture_control {
struct compact_control *cc;
struct page *page;
unsigned long
isolate_freepages_range(struct compact_control *cc,
unsigned long start_pfn, unsigned long end_pfn);
unsigned long
isolate_migratepages_range(struct compact_control *cc,
unsigned long low_pfn, unsigned long end_pfn);
int find_suitable_fallback(struct free_area *area, unsigned int order,
int migratetype, bool only_stealable, bool *can_steal);
* This function returns the order of a free page in the buddy system. In
* general, page_zone(page)->lock must be held by the caller to prevent the
* page from being allocated in parallel and returning garbage as the order.
* If a caller does not hold page_zone(page)->lock, it must guarantee that the
* page cannot be allocated or merged in parallel. Alternatively, it must
* handle invalid values gracefully, and use page_order_unsafe() below.
static inline unsigned int page_order(struct page *page)
/* PageBuddy() must be checked by the caller */
return page_private(page);
* Like page_order(), but for callers who cannot afford to hold the zone lock.
* PageBuddy() should be checked first by the caller to minimize race window,
* and invalid values must be handled gracefully.
* READ_ONCE is used so that if the caller assigns the result into a local
* variable and e.g. tests it for valid range before using, the compiler cannot
* decide to remove the variable and inline the page_private(page) multiple
* times, potentially observing different values in the tests and the actual
* use of the result.
#define page_order_unsafe(page) READ_ONCE(page_private(page))
static inline bool is_cow_mapping(vm_flags_t flags)
return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
* These three helpers classifies VMAs for virtual memory accounting.
* Executable code area - executable, not writable, not stack
static inline bool is_exec_mapping(vm_flags_t flags)
return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
* Stack area - atomatically grows in one direction
* VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
* do_mmap() forbids all other combinations.
static inline bool is_stack_mapping(vm_flags_t flags)
return (flags & VM_STACK) == VM_STACK;
* Data area - private, writable, not stack
static inline bool is_data_mapping(vm_flags_t flags)
return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
/* mm/util.c */
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev);
void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma);
extern long populate_vma_page_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end, int *nonblocking);
extern void munlock_vma_pages_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
* must be called with vma's mmap_sem held for read or write, and page locked.
extern void mlock_vma_page(struct page *page);
extern unsigned int munlock_vma_page(struct page *page);
* Clear the page's PageMlocked(). This can be useful in a situation where
* we want to unconditionally remove a page from the pagecache -- e.g.,
* on truncation or freeing.
* It is legal to call this function for any page, mlocked or not.
* If called for a page that is still mapped by mlocked vmas, all we do
* is revert to lazy LRU behaviour -- semantics are not broken.
extern void clear_page_mlock(struct page *page);
* mlock_migrate_page - called only from migrate_misplaced_transhuge_page()
* (because that does not go through the full procedure of migration ptes):
* to migrate the Mlocked page flag; update statistics.
static inline void mlock_migrate_page(struct page *newpage, struct page *page)
if (TestClearPageMlocked(page)) {
int nr_pages = hpage_nr_pages(page);
/* Holding pmd lock, no change in irq context: __mod is safe */
__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
__mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
* At what user virtual address is page expected in @vma?
static inline unsigned long
__vma_address(struct page *page, struct vm_area_struct *vma)
pgoff_t pgoff = page_to_pgoff(page);
return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
static inline unsigned long
vma_address(struct page *page, struct vm_area_struct *vma)
unsigned long start, end;
start = __vma_address(page, vma);
end = start + PAGE_SIZE * (hpage_nr_pages(page) - 1);
/* page should be within @vma mapping range */
VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma);
return max(start, vma->vm_start);
static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
struct file *fpin)
int flags = vmf->flags;
if (fpin)
return fpin;
* FAULT_FLAG_RETRY_NOWAIT means we don't want to wait on page locks or
* anything, so we only pin the file and drop the mmap_sem if only
* FAULT_FLAG_ALLOW_RETRY is set, while this is the first attempt.
if (fault_flag_allow_retry_first(flags) &&
fpin = get_file(vmf->vma->vm_file);
return fpin;
#else /* !CONFIG_MMU */
static inline void clear_page_mlock(struct page *page) { }
static inline void mlock_vma_page(struct page *page) { }
static inline void mlock_migrate_page(struct page *new, struct page *old) { }
#endif /* !CONFIG_MMU */
* Return the mem_map entry representing the 'offset' subpage within
* the maximally aligned gigantic page 'base'. Handle any discontiguity
* in the mem_map at MAX_ORDER_NR_PAGES boundaries.
static inline struct page *mem_map_offset(struct page *base, int offset)
if (unlikely(offset >= MAX_ORDER_NR_PAGES))
return nth_page(base, offset);
return base + offset;
* Iterator over all subpages within the maximally aligned gigantic
* page 'base'. Handle any discontiguity in the mem_map.
static inline struct page *mem_map_next(struct page *iter,
struct page *base, int offset)
if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
unsigned long pfn = page_to_pfn(base) + offset;
if (!pfn_valid(pfn))
return NULL;
return pfn_to_page(pfn);
return iter + 1;
/* Memory initialisation debug and verification */
enum mminit_level {
extern int mminit_loglevel;
#define mminit_dprintk(level, prefix, fmt, arg...) \
do { \
if (level < mminit_loglevel) { \
if (level <= MMINIT_WARNING) \
pr_warn("mminit::" prefix " " fmt, ##arg); \
else \
printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
} \
} while (0)
extern void mminit_verify_pageflags_layout(void);
extern void mminit_verify_zonelist(void);
static inline void mminit_dprintk(enum mminit_level level,
const char *prefix, const char *fmt, ...)
static inline void mminit_verify_pageflags_layout(void)
static inline void mminit_verify_zonelist(void)
/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
unsigned long *end_pfn);
static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
unsigned long *end_pfn)
extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
unsigned int order)
extern int hwpoison_filter(struct page *p);
extern u32 hwpoison_filter_dev_major;
extern u32 hwpoison_filter_dev_minor;
extern u64 hwpoison_filter_flags_mask;
extern u64 hwpoison_filter_flags_value;
extern u64 hwpoison_filter_memcg;
extern u32 hwpoison_filter_enable;
extern unsigned long __must_check vm_mmap_pgoff(struct file *, unsigned long,
unsigned long, unsigned long,
unsigned long, unsigned long);
extern void set_pageblock_order(void);
unsigned long reclaim_clean_pages_from_list(struct zone *zone,
struct list_head *page_list);
/* The ALLOC_WMARK bits are used as an index to zone->watermark */
#define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
/* Mask to get the watermark bits */
* Only MMU archs have async oom victim reclaim - aka oom_reaper so we
* cannot assume a reduced access to memory reserves is sufficient for
* !MMU
#define ALLOC_OOM 0x08
#define ALLOC_HARDER 0x10 /* try to alloc harder */
#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
#define ALLOC_CMA 0x80 /* allow allocations from CMA areas */
#define ALLOC_NOFRAGMENT 0x100 /* avoid mixing pageblock types */
#define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
enum ttu_flags;
struct tlbflush_unmap_batch;
* only for MM internal work items which do not depend on
* any allocations or locks which might depend on allocations
extern struct workqueue_struct *mm_percpu_wq;
void try_to_unmap_flush(void);
void try_to_unmap_flush_dirty(void);
void flush_tlb_batched_pending(struct mm_struct *mm);
static inline void try_to_unmap_flush(void)
static inline void try_to_unmap_flush_dirty(void)
static inline void flush_tlb_batched_pending(struct mm_struct *mm)
extern const struct trace_print_flags pageflag_names[];
extern const struct trace_print_flags vmaflag_names[];
extern const struct trace_print_flags gfpflag_names[];
static inline bool is_migrate_highatomic(enum migratetype migratetype)
return migratetype == MIGRATE_HIGHATOMIC;
static inline bool is_migrate_highatomic_page(struct page *page)
return get_pageblock_migratetype(page) == MIGRATE_HIGHATOMIC;
void setup_zone_pageset(struct zone *zone);
extern struct page *alloc_new_node_page(struct page *page, unsigned long node);
#endif /* __MM_INTERNAL_H */