1 #ifndef _LINUX_MM_TYPES_H
2 #define _LINUX_MM_TYPES_H
4 #include <linux/auxvec.h>
5 #include <linux/types.h>
6 #include <linux/threads.h>
7 #include <linux/list.h>
8 #include <linux/spinlock.h>
9 #include <linux/rbtree.h>
10 #include <linux/rwsem.h>
11 #include <linux/completion.h>
12 #include <linux/cpumask.h>
13 #include <linux/uprobes.h>
14 #include <linux/page-flags-layout.h>
18 #ifndef AT_VECTOR_SIZE_ARCH
19 #define AT_VECTOR_SIZE_ARCH 0
21 #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
26 #define USE_SPLIT_PTE_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
27 #define USE_SPLIT_PMD_PTLOCKS (USE_SPLIT_PTE_PTLOCKS && \
28 IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
29 #define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)
31 typedef void compound_page_dtor(struct page
*);
34 * Each physical page in the system has a struct page associated with
35 * it to keep track of whatever it is we are using the page for at the
36 * moment. Note that we have no way to track which tasks are using
37 * a page, though if it is a pagecache page, rmap structures can tell us
40 * The objects in struct page are organized in double word blocks in
41 * order to allows us to use atomic double word operations on portions
42 * of struct page. That is currently only used by slub but the arrangement
43 * allows the use of atomic double word operations on the flags/mapping
44 * and lru list pointers also.
47 /* First double word block */
48 unsigned long flags
; /* Atomic flags, some possibly
49 * updated asynchronously */
51 struct address_space
*mapping
; /* If low bit clear, points to
52 * inode address_space, or NULL.
53 * If page mapped as anonymous
54 * memory, low bit is set, and
55 * it points to anon_vma object:
56 * see PAGE_MAPPING_ANON below.
58 void *s_mem
; /* slab first object */
61 /* Second double word */
64 pgoff_t index
; /* Our offset within mapping. */
65 void *freelist
; /* sl[aou]b first free object */
69 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
70 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
71 /* Used for cmpxchg_double in slub */
72 unsigned long counters
;
75 * Keep _count separate from slub cmpxchg_double data.
76 * As the rest of the double word is protected by
77 * slab_lock but _count is not.
86 * Count of ptes mapped in
87 * mms, to show when page is
88 * mapped & limit reverse map
91 * Used also for tail pages
92 * refcounting instead of
93 * _count. Tail pages cannot
94 * be mapped and keeping the
95 * tail page _count zero at
96 * all times guarantees
97 * get_page_unless_zero() will
98 * never succeed on tail
108 int units
; /* SLOB */
110 atomic_t _count
; /* Usage count, see below. */
112 unsigned int active
; /* SLAB */
116 /* Third double word block */
118 struct list_head lru
; /* Pageout list, eg. active_list
119 * protected by zone->lru_lock !
120 * Can be used as a generic list
123 struct { /* slub per cpu partial pages */
124 struct page
*next
; /* Next partial slab */
126 int pages
; /* Nr of partial slabs left */
127 int pobjects
; /* Approximate # of objects */
134 struct slab
*slab_page
; /* slab fields */
135 struct rcu_head rcu_head
; /* Used by SLAB
136 * when destroying via RCU
138 /* First tail page of compound page */
140 compound_page_dtor
*compound_dtor
;
141 unsigned long compound_order
;
144 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
145 pgtable_t pmd_huge_pte
; /* protected by page->ptl */
149 /* Remainder is not double word aligned */
151 unsigned long private; /* Mapping-private opaque data:
152 * usually used for buffer_heads
153 * if PagePrivate set; used for
154 * swp_entry_t if PageSwapCache;
155 * indicates order in the buddy
156 * system if PG_buddy is set.
158 #if USE_SPLIT_PTE_PTLOCKS
159 #if ALLOC_SPLIT_PTLOCKS
165 struct kmem_cache
*slab_cache
; /* SL[AU]B: Pointer to slab */
166 struct page
*first_page
; /* Compound tail pages */
170 struct mem_cgroup
*mem_cgroup
;
174 * On machines where all RAM is mapped into kernel address space,
175 * we can simply calculate the virtual address. On machines with
176 * highmem some memory is mapped into kernel virtual memory
177 * dynamically, so we need a place to store that address.
178 * Note that this field could be 16 bits on x86 ... ;)
180 * Architectures with slow multiplication can define
181 * WANT_PAGE_VIRTUAL in asm/page.h
183 #if defined(WANT_PAGE_VIRTUAL)
184 void *virtual; /* Kernel virtual address (NULL if
185 not kmapped, ie. highmem) */
186 #endif /* WANT_PAGE_VIRTUAL */
188 #ifdef CONFIG_KMEMCHECK
190 * kmemcheck wants to track the status of each byte in a page; this
191 * is a pointer to such a status block. NULL if not tracked.
196 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
201 * The struct page can be forced to be double word aligned so that atomic ops
202 * on double words work. The SLUB allocator can make use of such a feature.
204 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
205 __aligned(2 * sizeof(unsigned long))
211 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
220 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
221 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
223 struct page_frag_cache
{
225 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
231 /* we maintain a pagecount bias, so that we dont dirty cache line
232 * containing page->_count every time we allocate a fragment.
234 unsigned int pagecnt_bias
;
238 typedef unsigned long vm_flags_t
;
241 * A region containing a mapping of a non-memory backed file under NOMMU
242 * conditions. These are held in a global tree and are pinned by the VMAs that
246 struct rb_node vm_rb
; /* link in global region tree */
247 vm_flags_t vm_flags
; /* VMA vm_flags */
248 unsigned long vm_start
; /* start address of region */
249 unsigned long vm_end
; /* region initialised to here */
250 unsigned long vm_top
; /* region allocated to here */
251 unsigned long vm_pgoff
; /* the offset in vm_file corresponding to vm_start */
252 struct file
*vm_file
; /* the backing file or NULL */
254 int vm_usage
; /* region usage count (access under nommu_region_sem) */
255 bool vm_icache_flushed
: 1; /* true if the icache has been flushed for
259 #ifdef CONFIG_USERFAULTFD
260 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
261 struct vm_userfaultfd_ctx
{
262 struct userfaultfd_ctx
*ctx
;
264 #else /* CONFIG_USERFAULTFD */
265 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
266 struct vm_userfaultfd_ctx
{};
267 #endif /* CONFIG_USERFAULTFD */
270 * This struct defines a memory VMM memory area. There is one of these
271 * per VM-area/task. A VM area is any part of the process virtual memory
272 * space that has a special rule for the page-fault handlers (ie a shared
273 * library, the executable area etc).
275 struct vm_area_struct
{
276 /* The first cache line has the info for VMA tree walking. */
278 unsigned long vm_start
; /* Our start address within vm_mm. */
279 unsigned long vm_end
; /* The first byte after our end address
282 /* linked list of VM areas per task, sorted by address */
283 struct vm_area_struct
*vm_next
, *vm_prev
;
285 struct rb_node vm_rb
;
288 * Largest free memory gap in bytes to the left of this VMA.
289 * Either between this VMA and vma->vm_prev, or between one of the
290 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
291 * get_unmapped_area find a free area of the right size.
293 unsigned long rb_subtree_gap
;
295 /* Second cache line starts here. */
297 struct mm_struct
*vm_mm
; /* The address space we belong to. */
298 pgprot_t vm_page_prot
; /* Access permissions of this VMA. */
299 unsigned long vm_flags
; /* Flags, see mm.h. */
302 * For areas with an address space and backing store,
303 * linkage into the address_space->i_mmap interval tree.
307 unsigned long rb_subtree_last
;
311 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
312 * list, after a COW of one of the file pages. A MAP_SHARED vma
313 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
314 * or brk vma (with NULL file) can only be in an anon_vma list.
316 struct list_head anon_vma_chain
; /* Serialized by mmap_sem &
318 struct anon_vma
*anon_vma
; /* Serialized by page_table_lock */
320 /* Function pointers to deal with this struct. */
321 const struct vm_operations_struct
*vm_ops
;
323 /* Information about our backing store: */
324 unsigned long vm_pgoff
; /* Offset (within vm_file) in PAGE_SIZE
325 units, *not* PAGE_CACHE_SIZE */
326 struct file
* vm_file
; /* File we map to (can be NULL). */
327 void * vm_private_data
; /* was vm_pte (shared mem) */
330 struct vm_region
*vm_region
; /* NOMMU mapping region */
333 struct mempolicy
*vm_policy
; /* NUMA policy for the VMA */
335 struct vm_userfaultfd_ctx vm_userfaultfd_ctx
;
339 struct task_struct
*task
;
340 struct core_thread
*next
;
345 struct core_thread dumper
;
346 struct completion startup
;
356 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
357 #define SPLIT_RSS_COUNTING
358 /* per-thread cached information, */
359 struct task_rss_stat
{
360 int events
; /* for synchronization threshold */
361 int count
[NR_MM_COUNTERS
];
363 #endif /* USE_SPLIT_PTE_PTLOCKS */
366 atomic_long_t count
[NR_MM_COUNTERS
];
371 struct vm_area_struct
*mmap
; /* list of VMAs */
372 struct rb_root mm_rb
;
373 u32 vmacache_seqnum
; /* per-thread vmacache */
375 unsigned long (*get_unmapped_area
) (struct file
*filp
,
376 unsigned long addr
, unsigned long len
,
377 unsigned long pgoff
, unsigned long flags
);
379 unsigned long mmap_base
; /* base of mmap area */
380 unsigned long mmap_legacy_base
; /* base of mmap area in bottom-up allocations */
381 unsigned long task_size
; /* size of task vm space */
382 unsigned long highest_vm_end
; /* highest vma end address */
384 atomic_t mm_users
; /* How many users with user space? */
385 atomic_t mm_count
; /* How many references to "struct mm_struct" (users count as 1) */
386 atomic_long_t nr_ptes
; /* PTE page table pages */
387 #if CONFIG_PGTABLE_LEVELS > 2
388 atomic_long_t nr_pmds
; /* PMD page table pages */
390 int map_count
; /* number of VMAs */
392 spinlock_t page_table_lock
; /* Protects page tables and some counters */
393 struct rw_semaphore mmap_sem
;
395 struct list_head mmlist
; /* List of maybe swapped mm's. These are globally strung
396 * together off init_mm.mmlist, and are protected
401 unsigned long hiwater_rss
; /* High-watermark of RSS usage */
402 unsigned long hiwater_vm
; /* High-water virtual memory usage */
404 unsigned long total_vm
; /* Total pages mapped */
405 unsigned long locked_vm
; /* Pages that have PG_mlocked set */
406 unsigned long pinned_vm
; /* Refcount permanently increased */
407 unsigned long shared_vm
; /* Shared pages (files) */
408 unsigned long exec_vm
; /* VM_EXEC & ~VM_WRITE */
409 unsigned long stack_vm
; /* VM_GROWSUP/DOWN */
410 unsigned long def_flags
;
411 unsigned long start_code
, end_code
, start_data
, end_data
;
412 unsigned long start_brk
, brk
, start_stack
;
413 unsigned long arg_start
, arg_end
, env_start
, env_end
;
415 unsigned long saved_auxv
[AT_VECTOR_SIZE
]; /* for /proc/PID/auxv */
418 * Special counters, in some configurations protected by the
419 * page_table_lock, in other configurations by being atomic.
421 struct mm_rss_stat rss_stat
;
423 struct linux_binfmt
*binfmt
;
425 cpumask_var_t cpu_vm_mask_var
;
427 /* Architecture-specific MM context */
428 mm_context_t context
;
430 unsigned long flags
; /* Must use atomic bitops to access the bits */
432 struct core_state
*core_state
; /* coredumping support */
434 spinlock_t ioctx_lock
;
435 struct kioctx_table __rcu
*ioctx_table
;
439 * "owner" points to a task that is regarded as the canonical
440 * user/owner of this mm. All of the following must be true in
441 * order for it to be changed:
443 * current == mm->owner
445 * new_owner->mm == mm
446 * new_owner->alloc_lock is held
448 struct task_struct __rcu
*owner
;
451 /* store ref to file /proc/<pid>/exe symlink points to */
452 struct file __rcu
*exe_file
;
453 #ifdef CONFIG_MMU_NOTIFIER
454 struct mmu_notifier_mm
*mmu_notifier_mm
;
456 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
457 pgtable_t pmd_huge_pte
; /* protected by page_table_lock */
459 #ifdef CONFIG_CPUMASK_OFFSTACK
460 struct cpumask cpumask_allocation
;
462 #ifdef CONFIG_NUMA_BALANCING
464 * numa_next_scan is the next time that the PTEs will be marked
465 * pte_numa. NUMA hinting faults will gather statistics and migrate
466 * pages to new nodes if necessary.
468 unsigned long numa_next_scan
;
470 /* Restart point for scanning and setting pte_numa */
471 unsigned long numa_scan_offset
;
473 /* numa_scan_seq prevents two threads setting pte_numa */
476 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
478 * An operation with batched TLB flushing is going on. Anything that
479 * can move process memory needs to flush the TLB when moving a
480 * PROT_NONE or PROT_NUMA mapped page.
482 bool tlb_flush_pending
;
484 struct uprobes_state uprobes_state
;
485 #ifdef CONFIG_X86_INTEL_MPX
486 /* address of the bounds directory */
487 void __user
*bd_addr
;
491 static inline void mm_init_cpumask(struct mm_struct
*mm
)
493 #ifdef CONFIG_CPUMASK_OFFSTACK
494 mm
->cpu_vm_mask_var
= &mm
->cpumask_allocation
;
496 cpumask_clear(mm
->cpu_vm_mask_var
);
499 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
500 static inline cpumask_t
*mm_cpumask(struct mm_struct
*mm
)
502 return mm
->cpu_vm_mask_var
;
505 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
507 * Memory barriers to keep this state in sync are graciously provided by
508 * the page table locks, outside of which no page table modifications happen.
509 * The barriers below prevent the compiler from re-ordering the instructions
510 * around the memory barriers that are already present in the code.
512 static inline bool mm_tlb_flush_pending(struct mm_struct
*mm
)
515 return mm
->tlb_flush_pending
;
517 static inline void set_tlb_flush_pending(struct mm_struct
*mm
)
519 mm
->tlb_flush_pending
= true;
522 * Guarantee that the tlb_flush_pending store does not leak into the
523 * critical section updating the page tables
525 smp_mb__before_spinlock();
527 /* Clearing is done after a TLB flush, which also provides a barrier. */
528 static inline void clear_tlb_flush_pending(struct mm_struct
*mm
)
531 mm
->tlb_flush_pending
= false;
534 static inline bool mm_tlb_flush_pending(struct mm_struct
*mm
)
538 static inline void set_tlb_flush_pending(struct mm_struct
*mm
)
541 static inline void clear_tlb_flush_pending(struct mm_struct
*mm
)
546 struct vm_special_mapping
552 enum tlb_flush_reason
{
553 TLB_FLUSH_ON_TASK_SWITCH
,
554 TLB_REMOTE_SHOOTDOWN
,
556 TLB_LOCAL_MM_SHOOTDOWN
,
558 NR_TLB_FLUSH_REASONS
,
562 * A swap entry has to fit into a "unsigned long", as the entry is hidden
563 * in the "index" field of the swapper address space.
569 #endif /* _LINUX_MM_TYPES_H */