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#include <linux/auxvec.h>
#include <linux/types.h>
#include <linux/threads.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
#include <linux/uprobes.h>
#include <linux/page-flags-layout.h>
#include <asm/page.h>
#include <asm/mmu.h>
struct address_space;
struct mem_cgroup;
typedef void compound_page_dtor(struct page *);
* Each physical page in the system has a struct page associated with
* it to keep track of whatever it is we are using the page for at the
* moment. Note that we have no way to track which tasks are using
* a page, though if it is a pagecache page, rmap structures can tell us
* who is mapping it.
* The objects in struct page are organized in double word blocks in
* order to allows us to use atomic double word operations on portions
* of struct page. That is currently only used by slub but the arrangement
* allows the use of atomic double word operations on the flags/mapping
* and lru list pointers also.
struct page {
/* First double word block */
unsigned long flags; /* Atomic flags, some possibly
* updated asynchronously */
union {
struct address_space *mapping; /* If low bit clear, points to
* inode address_space, or NULL.
* If page mapped as anonymous
* memory, low bit is set, and
* it points to anon_vma object:
* see PAGE_MAPPING_ANON below.
void *s_mem; /* slab first object */
/* Second double word */
struct {
union {
pgoff_t index; /* Our offset within mapping. */
void *freelist; /* sl[aou]b first free object */
union {
/* Used for cmpxchg_double in slub */
unsigned long counters;
* Keep _count separate from slub cmpxchg_double data.
* As the rest of the double word is protected by
* slab_lock but _count is not.
unsigned counters;
struct {
union {
* Count of ptes mapped in
* mms, to show when page is
* mapped & limit reverse map
* searches.
* Used also for tail pages
* refcounting instead of
* _count. Tail pages cannot
* be mapped and keeping the
* tail page _count zero at
* all times guarantees
* get_page_unless_zero() will
* never succeed on tail
* pages.
atomic_t _mapcount;
struct { /* SLUB */
unsigned inuse:16;
unsigned objects:15;
unsigned frozen:1;
int units; /* SLOB */
atomic_t _count; /* Usage count, see below. */
unsigned int active; /* SLAB */
/* Third double word block */
union {
struct list_head lru; /* Pageout list, eg. active_list
* protected by zone->lru_lock !
* Can be used as a generic list
* by the page owner.
struct { /* slub per cpu partial pages */
struct page *next; /* Next partial slab */
#ifdef CONFIG_64BIT
int pages; /* Nr of partial slabs left */
int pobjects; /* Approximate # of objects */
short int pages;
short int pobjects;
struct slab *slab_page; /* slab fields */
struct rcu_head rcu_head; /* Used by SLAB
* when destroying via RCU
/* First tail page of compound page */
struct {
compound_page_dtor *compound_dtor;
unsigned long compound_order;
pgtable_t pmd_huge_pte; /* protected by page->ptl */
/* Remainder is not double word aligned */
union {
unsigned long private; /* Mapping-private opaque data:
* usually used for buffer_heads
* if PagePrivate set; used for
* swp_entry_t if PageSwapCache;
* indicates order in the buddy
* system if PG_buddy is set.
spinlock_t *ptl;
spinlock_t ptl;
struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */
struct page *first_page; /* Compound tail pages */
struct mem_cgroup *mem_cgroup;
* On machines where all RAM is mapped into kernel address space,
* we can simply calculate the virtual address. On machines with
* highmem some memory is mapped into kernel virtual memory
* dynamically, so we need a place to store that address.
* Note that this field could be 16 bits on x86 ... ;)
* Architectures with slow multiplication can define
* WANT_PAGE_VIRTUAL in asm/page.h
#if defined(WANT_PAGE_VIRTUAL)
void *virtual; /* Kernel virtual address (NULL if
not kmapped, ie. highmem) */
#endif /* WANT_PAGE_VIRTUAL */
* kmemcheck wants to track the status of each byte in a page; this
* is a pointer to such a status block. NULL if not tracked.
void *shadow;
int _last_cpupid;
* The struct page can be forced to be double word aligned so that atomic ops
* on double words work. The SLUB allocator can make use of such a feature.
__aligned(2 * sizeof(unsigned long))
struct page_frag {
struct page *page;
#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
__u32 offset;
__u32 size;
__u16 offset;
__u16 size;
struct page_frag_cache {
void * va;
__u16 offset;
__u16 size;
__u32 offset;
/* we maintain a pagecount bias, so that we dont dirty cache line
* containing page->_count every time we allocate a fragment.
unsigned int pagecnt_bias;
bool pfmemalloc;
typedef unsigned long vm_flags_t;
* A region containing a mapping of a non-memory backed file under NOMMU
* conditions. These are held in a global tree and are pinned by the VMAs that
* map parts of them.
struct vm_region {
struct rb_node vm_rb; /* link in global region tree */
vm_flags_t vm_flags; /* VMA vm_flags */
unsigned long vm_start; /* start address of region */
unsigned long vm_end; /* region initialised to here */
unsigned long vm_top; /* region allocated to here */
unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
struct file *vm_file; /* the backing file or NULL */
int vm_usage; /* region usage count (access under nommu_region_sem) */
bool vm_icache_flushed : 1; /* true if the icache has been flushed for
* this region */
#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
struct vm_userfaultfd_ctx {
struct userfaultfd_ctx *ctx;
#define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
struct vm_userfaultfd_ctx {};
* This struct defines a memory VMM memory area. There is one of these
* per VM-area/task. A VM area is any part of the process virtual memory
* space that has a special rule for the page-fault handlers (ie a shared
* library, the executable area etc).
struct vm_area_struct {
/* The first cache line has the info for VMA tree walking. */
unsigned long vm_start; /* Our start address within vm_mm. */
unsigned long vm_end; /* The first byte after our end address
within vm_mm. */
/* linked list of VM areas per task, sorted by address */
struct vm_area_struct *vm_next, *vm_prev;
struct rb_node vm_rb;
* Largest free memory gap in bytes to the left of this VMA.
* Either between this VMA and vma->vm_prev, or between one of the
* VMAs below us in the VMA rbtree and its ->vm_prev. This helps
* get_unmapped_area find a free area of the right size.
unsigned long rb_subtree_gap;
/* Second cache line starts here. */
struct mm_struct *vm_mm; /* The address space we belong to. */
pgprot_t vm_page_prot; /* Access permissions of this VMA. */
unsigned long vm_flags; /* Flags, see mm.h. */
* For areas with an address space and backing store,
* linkage into the address_space->i_mmap interval tree.
struct {
struct rb_node rb;
unsigned long rb_subtree_last;
} shared;
* A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
* list, after a COW of one of the file pages. A MAP_SHARED vma
* can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
* or brk vma (with NULL file) can only be in an anon_vma list.
struct list_head anon_vma_chain; /* Serialized by mmap_sem &
* page_table_lock */
struct anon_vma *anon_vma; /* Serialized by page_table_lock */
/* Function pointers to deal with this struct. */
const struct vm_operations_struct *vm_ops;
/* Information about our backing store: */
unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
units, *not* PAGE_CACHE_SIZE */
struct file * vm_file; /* File we map to (can be NULL). */
void * vm_private_data; /* was vm_pte (shared mem) */
#ifndef CONFIG_MMU
struct vm_region *vm_region; /* NOMMU mapping region */
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
struct core_thread {
struct task_struct *task;
struct core_thread *next;
struct core_state {
atomic_t nr_threads;
struct core_thread dumper;
struct completion startup;
enum {
/* per-thread cached information, */
struct task_rss_stat {
int events; /* for synchronization threshold */
int count[NR_MM_COUNTERS];
struct mm_rss_stat {
atomic_long_t count[NR_MM_COUNTERS];
struct kioctx_table;
struct mm_struct {
struct vm_area_struct *mmap; /* list of VMAs */
struct rb_root mm_rb;
u32 vmacache_seqnum; /* per-thread vmacache */
unsigned long (*get_unmapped_area) (struct file *filp,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags);
unsigned long mmap_base; /* base of mmap area */
unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
unsigned long task_size; /* size of task vm space */
unsigned long highest_vm_end; /* highest vma end address */
pgd_t * pgd;
atomic_t mm_users; /* How many users with user space? */
atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
atomic_long_t nr_ptes; /* PTE page table pages */
atomic_long_t nr_pmds; /* PMD page table pages */
int map_count; /* number of VMAs */
spinlock_t page_table_lock; /* Protects page tables and some counters */
struct rw_semaphore mmap_sem;
struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
* together off init_mm.mmlist, and are protected
* by mmlist_lock
unsigned long hiwater_rss; /* High-watermark of RSS usage */
unsigned long hiwater_vm; /* High-water virtual memory usage */
unsigned long total_vm; /* Total pages mapped */
unsigned long locked_vm; /* Pages that have PG_mlocked set */
unsigned long pinned_vm; /* Refcount permanently increased */
unsigned long shared_vm; /* Shared pages (files) */
unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */
unsigned long stack_vm; /* VM_GROWSUP/DOWN */
unsigned long def_flags;
unsigned long start_code, end_code, start_data, end_data;
unsigned long start_brk, brk, start_stack;
unsigned long arg_start, arg_end, env_start, env_end;
unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
* Special counters, in some configurations protected by the
* page_table_lock, in other configurations by being atomic.
struct mm_rss_stat rss_stat;
struct linux_binfmt *binfmt;
cpumask_var_t cpu_vm_mask_var;
/* Architecture-specific MM context */
mm_context_t context;
unsigned long flags; /* Must use atomic bitops to access the bits */
struct core_state *core_state; /* coredumping support */
spinlock_t ioctx_lock;
struct kioctx_table __rcu *ioctx_table;
* "owner" points to a task that is regarded as the canonical
* user/owner of this mm. All of the following must be true in
* order for it to be changed:
* current == mm->owner
* current->mm != mm
* new_owner->mm == mm
* new_owner->alloc_lock is held
struct task_struct __rcu *owner;
/* store ref to file /proc/<pid>/exe symlink points to */
struct file __rcu *exe_file;
struct mmu_notifier_mm *mmu_notifier_mm;
pgtable_t pmd_huge_pte; /* protected by page_table_lock */
struct cpumask cpumask_allocation;
* numa_next_scan is the next time that the PTEs will be marked
* pte_numa. NUMA hinting faults will gather statistics and migrate
* pages to new nodes if necessary.
unsigned long numa_next_scan;
/* Restart point for scanning and setting pte_numa */
unsigned long numa_scan_offset;
/* numa_scan_seq prevents two threads setting pte_numa */
int numa_scan_seq;
* An operation with batched TLB flushing is going on. Anything that
* can move process memory needs to flush the TLB when moving a
* PROT_NONE or PROT_NUMA mapped page.
bool tlb_flush_pending;
struct uprobes_state uprobes_state;
/* address of the bounds directory */
void __user *bd_addr;
static inline void mm_init_cpumask(struct mm_struct *mm)
mm->cpu_vm_mask_var = &mm->cpumask_allocation;
/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
return mm->cpu_vm_mask_var;
* Memory barriers to keep this state in sync are graciously provided by
* the page table locks, outside of which no page table modifications happen.
* The barriers below prevent the compiler from re-ordering the instructions
* around the memory barriers that are already present in the code.
static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
return mm->tlb_flush_pending;
static inline void set_tlb_flush_pending(struct mm_struct *mm)
mm->tlb_flush_pending = true;
* Guarantee that the tlb_flush_pending store does not leak into the
* critical section updating the page tables
/* Clearing is done after a TLB flush, which also provides a barrier. */
static inline void clear_tlb_flush_pending(struct mm_struct *mm)
mm->tlb_flush_pending = false;
static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
return false;
static inline void set_tlb_flush_pending(struct mm_struct *mm)
static inline void clear_tlb_flush_pending(struct mm_struct *mm)
struct vm_special_mapping
const char *name;
struct page **pages;
enum tlb_flush_reason {
* A swap entry has to fit into a "unsigned long", as the entry is hidden
* in the "index" field of the swapper address space.
typedef struct {
unsigned long val;
} swp_entry_t;
#endif /* _LINUX_MM_TYPES_H */
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