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/page-debug-flags.h>
14 #include <linux/uprobes.h>
15 #include <linux/page-flags-layout.h>
19 #ifndef AT_VECTOR_SIZE_ARCH
20 #define AT_VECTOR_SIZE_ARCH 0
22 #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)
32 * Each physical page in the system has a struct page associated with
33 * it to keep track of whatever it is we are using the page for at the
34 * moment. Note that we have no way to track which tasks are using
35 * a page, though if it is a pagecache page, rmap structures can tell us
38 * The objects in struct page are organized in double word blocks in
39 * order to allows us to use atomic double word operations on portions
40 * of struct page. That is currently only used by slub but the arrangement
41 * allows the use of atomic double word operations on the flags/mapping
42 * and lru list pointers also.
45 /* First double word block */
46 unsigned long flags
; /* Atomic flags, some possibly
47 * updated asynchronously */
49 struct address_space
*mapping
; /* If low bit clear, points to
50 * inode address_space, or NULL.
51 * If page mapped as anonymous
52 * memory, low bit is set, and
53 * it points to anon_vma object:
54 * see PAGE_MAPPING_ANON below.
56 void *s_mem
; /* slab first object */
59 /* Second double word */
62 pgoff_t index
; /* Our offset within mapping. */
63 void *freelist
; /* sl[aou]b first free object */
64 bool pfmemalloc
; /* If set by the page allocator,
65 * ALLOC_NO_WATERMARKS was set
66 * and the low watermark was not
67 * met implying that the system
68 * is under some pressure. The
69 * caller should try ensure
70 * this page is only used to
76 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
77 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
78 /* Used for cmpxchg_double in slub */
79 unsigned long counters
;
82 * Keep _count separate from slub cmpxchg_double data.
83 * As the rest of the double word is protected by
84 * slab_lock but _count is not.
93 * Count of ptes mapped in
94 * mms, to show when page is
95 * mapped & limit reverse map
98 * Used also for tail pages
99 * refcounting instead of
100 * _count. Tail pages cannot
101 * be mapped and keeping the
102 * tail page _count zero at
103 * all times guarantees
104 * get_page_unless_zero() will
105 * never succeed on tail
115 int units
; /* SLOB */
117 atomic_t _count
; /* Usage count, see below. */
119 unsigned int active
; /* SLAB */
123 /* Third double word block */
125 struct list_head lru
; /* Pageout list, eg. active_list
126 * protected by zone->lru_lock !
127 * Can be used as a generic list
130 struct { /* slub per cpu partial pages */
131 struct page
*next
; /* Next partial slab */
133 int pages
; /* Nr of partial slabs left */
134 int pobjects
; /* Approximate # of objects */
141 struct slab
*slab_page
; /* slab fields */
142 struct rcu_head rcu_head
; /* Used by SLAB
143 * when destroying via RCU
145 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
146 pgtable_t pmd_huge_pte
; /* protected by page->ptl */
150 /* Remainder is not double word aligned */
152 unsigned long private; /* Mapping-private opaque data:
153 * usually used for buffer_heads
154 * if PagePrivate set; used for
155 * swp_entry_t if PageSwapCache;
156 * indicates order in the buddy
157 * system if PG_buddy is set.
159 #if USE_SPLIT_PTE_PTLOCKS
160 #if ALLOC_SPLIT_PTLOCKS
166 struct kmem_cache
*slab_cache
; /* SL[AU]B: Pointer to slab */
167 struct page
*first_page
; /* Compound tail pages */
171 * On machines where all RAM is mapped into kernel address space,
172 * we can simply calculate the virtual address. On machines with
173 * highmem some memory is mapped into kernel virtual memory
174 * dynamically, so we need a place to store that address.
175 * Note that this field could be 16 bits on x86 ... ;)
177 * Architectures with slow multiplication can define
178 * WANT_PAGE_VIRTUAL in asm/page.h
180 #if defined(WANT_PAGE_VIRTUAL)
181 void *virtual; /* Kernel virtual address (NULL if
182 not kmapped, ie. highmem) */
183 #endif /* WANT_PAGE_VIRTUAL */
184 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
185 unsigned long debug_flags
; /* Use atomic bitops on this */
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 typedef unsigned long __nocast vm_flags_t
;
223 * A region containing a mapping of a non-memory backed file under NOMMU
224 * conditions. These are held in a global tree and are pinned by the VMAs that
228 struct rb_node vm_rb
; /* link in global region tree */
229 vm_flags_t vm_flags
; /* VMA vm_flags */
230 unsigned long vm_start
; /* start address of region */
231 unsigned long vm_end
; /* region initialised to here */
232 unsigned long vm_top
; /* region allocated to here */
233 unsigned long vm_pgoff
; /* the offset in vm_file corresponding to vm_start */
234 struct file
*vm_file
; /* the backing file or NULL */
236 int vm_usage
; /* region usage count (access under nommu_region_sem) */
237 bool vm_icache_flushed
: 1; /* true if the icache has been flushed for
242 * This struct defines a memory VMM memory area. There is one of these
243 * per VM-area/task. A VM area is any part of the process virtual memory
244 * space that has a special rule for the page-fault handlers (ie a shared
245 * library, the executable area etc).
247 struct vm_area_struct
{
248 /* The first cache line has the info for VMA tree walking. */
250 unsigned long vm_start
; /* Our start address within vm_mm. */
251 unsigned long vm_end
; /* The first byte after our end address
254 /* linked list of VM areas per task, sorted by address */
255 struct vm_area_struct
*vm_next
, *vm_prev
;
257 struct rb_node vm_rb
;
260 * Largest free memory gap in bytes to the left of this VMA.
261 * Either between this VMA and vma->vm_prev, or between one of the
262 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
263 * get_unmapped_area find a free area of the right size.
265 unsigned long rb_subtree_gap
;
267 /* Second cache line starts here. */
269 struct mm_struct
*vm_mm
; /* The address space we belong to. */
270 pgprot_t vm_page_prot
; /* Access permissions of this VMA. */
271 unsigned long vm_flags
; /* Flags, see mm.h. */
274 * For areas with an address space and backing store,
275 * linkage into the address_space->i_mmap interval tree, or
276 * linkage of vma in the address_space->i_mmap_nonlinear list.
281 unsigned long rb_subtree_last
;
283 struct list_head nonlinear
;
287 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
288 * list, after a COW of one of the file pages. A MAP_SHARED vma
289 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
290 * or brk vma (with NULL file) can only be in an anon_vma list.
292 struct list_head anon_vma_chain
; /* Serialized by mmap_sem &
294 struct anon_vma
*anon_vma
; /* Serialized by page_table_lock */
296 /* Function pointers to deal with this struct. */
297 const struct vm_operations_struct
*vm_ops
;
299 /* Information about our backing store: */
300 unsigned long vm_pgoff
; /* Offset (within vm_file) in PAGE_SIZE
301 units, *not* PAGE_CACHE_SIZE */
302 struct file
* vm_file
; /* File we map to (can be NULL). */
303 void * vm_private_data
; /* was vm_pte (shared mem) */
306 struct vm_region
*vm_region
; /* NOMMU mapping region */
309 struct mempolicy
*vm_policy
; /* NUMA policy for the VMA */
314 struct task_struct
*task
;
315 struct core_thread
*next
;
320 struct core_thread dumper
;
321 struct completion startup
;
331 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
332 #define SPLIT_RSS_COUNTING
333 /* per-thread cached information, */
334 struct task_rss_stat
{
335 int events
; /* for synchronization threshold */
336 int count
[NR_MM_COUNTERS
];
338 #endif /* USE_SPLIT_PTE_PTLOCKS */
341 atomic_long_t count
[NR_MM_COUNTERS
];
346 struct vm_area_struct
*mmap
; /* list of VMAs */
347 struct rb_root mm_rb
;
348 u32 vmacache_seqnum
; /* per-thread vmacache */
350 unsigned long (*get_unmapped_area
) (struct file
*filp
,
351 unsigned long addr
, unsigned long len
,
352 unsigned long pgoff
, unsigned long flags
);
354 unsigned long mmap_base
; /* base of mmap area */
355 unsigned long mmap_legacy_base
; /* base of mmap area in bottom-up allocations */
356 unsigned long task_size
; /* size of task vm space */
357 unsigned long highest_vm_end
; /* highest vma end address */
359 atomic_t mm_users
; /* How many users with user space? */
360 atomic_t mm_count
; /* How many references to "struct mm_struct" (users count as 1) */
361 atomic_long_t nr_ptes
; /* Page table pages */
362 int map_count
; /* number of VMAs */
364 spinlock_t page_table_lock
; /* Protects page tables and some counters */
365 struct rw_semaphore mmap_sem
;
367 struct list_head mmlist
; /* List of maybe swapped mm's. These are globally strung
368 * together off init_mm.mmlist, and are protected
373 unsigned long hiwater_rss
; /* High-watermark of RSS usage */
374 unsigned long hiwater_vm
; /* High-water virtual memory usage */
376 unsigned long total_vm
; /* Total pages mapped */
377 unsigned long locked_vm
; /* Pages that have PG_mlocked set */
378 unsigned long pinned_vm
; /* Refcount permanently increased */
379 unsigned long shared_vm
; /* Shared pages (files) */
380 unsigned long exec_vm
; /* VM_EXEC & ~VM_WRITE */
381 unsigned long stack_vm
; /* VM_GROWSUP/DOWN */
382 unsigned long def_flags
;
383 unsigned long start_code
, end_code
, start_data
, end_data
;
384 unsigned long start_brk
, brk
, start_stack
;
385 unsigned long arg_start
, arg_end
, env_start
, env_end
;
387 unsigned long saved_auxv
[AT_VECTOR_SIZE
]; /* for /proc/PID/auxv */
390 * Special counters, in some configurations protected by the
391 * page_table_lock, in other configurations by being atomic.
393 struct mm_rss_stat rss_stat
;
395 struct linux_binfmt
*binfmt
;
397 cpumask_var_t cpu_vm_mask_var
;
399 /* Architecture-specific MM context */
400 mm_context_t context
;
402 unsigned long flags
; /* Must use atomic bitops to access the bits */
404 struct core_state
*core_state
; /* coredumping support */
406 spinlock_t ioctx_lock
;
407 struct kioctx_table __rcu
*ioctx_table
;
411 * "owner" points to a task that is regarded as the canonical
412 * user/owner of this mm. All of the following must be true in
413 * order for it to be changed:
415 * current == mm->owner
417 * new_owner->mm == mm
418 * new_owner->alloc_lock is held
420 struct task_struct __rcu
*owner
;
423 /* store ref to file /proc/<pid>/exe symlink points to */
424 struct file
*exe_file
;
425 #ifdef CONFIG_MMU_NOTIFIER
426 struct mmu_notifier_mm
*mmu_notifier_mm
;
428 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
429 pgtable_t pmd_huge_pte
; /* protected by page_table_lock */
431 #ifdef CONFIG_CPUMASK_OFFSTACK
432 struct cpumask cpumask_allocation
;
434 #ifdef CONFIG_NUMA_BALANCING
436 * numa_next_scan is the next time that the PTEs will be marked
437 * pte_numa. NUMA hinting faults will gather statistics and migrate
438 * pages to new nodes if necessary.
440 unsigned long numa_next_scan
;
442 /* Restart point for scanning and setting pte_numa */
443 unsigned long numa_scan_offset
;
445 /* numa_scan_seq prevents two threads setting pte_numa */
448 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
450 * An operation with batched TLB flushing is going on. Anything that
451 * can move process memory needs to flush the TLB when moving a
452 * PROT_NONE or PROT_NUMA mapped page.
454 bool tlb_flush_pending
;
456 struct uprobes_state uprobes_state
;
459 static inline void mm_init_cpumask(struct mm_struct
*mm
)
461 #ifdef CONFIG_CPUMASK_OFFSTACK
462 mm
->cpu_vm_mask_var
= &mm
->cpumask_allocation
;
464 cpumask_clear(mm
->cpu_vm_mask_var
);
467 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
468 static inline cpumask_t
*mm_cpumask(struct mm_struct
*mm
)
470 return mm
->cpu_vm_mask_var
;
473 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
475 * Memory barriers to keep this state in sync are graciously provided by
476 * the page table locks, outside of which no page table modifications happen.
477 * The barriers below prevent the compiler from re-ordering the instructions
478 * around the memory barriers that are already present in the code.
480 static inline bool mm_tlb_flush_pending(struct mm_struct
*mm
)
483 return mm
->tlb_flush_pending
;
485 static inline void set_tlb_flush_pending(struct mm_struct
*mm
)
487 mm
->tlb_flush_pending
= true;
490 * Guarantee that the tlb_flush_pending store does not leak into the
491 * critical section updating the page tables
493 smp_mb__before_spinlock();
495 /* Clearing is done after a TLB flush, which also provides a barrier. */
496 static inline void clear_tlb_flush_pending(struct mm_struct
*mm
)
499 mm
->tlb_flush_pending
= false;
502 static inline bool mm_tlb_flush_pending(struct mm_struct
*mm
)
506 static inline void set_tlb_flush_pending(struct mm_struct
*mm
)
509 static inline void clear_tlb_flush_pending(struct mm_struct
*mm
)
514 struct vm_special_mapping
520 enum tlb_flush_reason
{
521 TLB_FLUSH_ON_TASK_SWITCH
,
522 TLB_REMOTE_SHOOTDOWN
,
524 TLB_LOCAL_MM_SHOOTDOWN
,
525 NR_TLB_FLUSH_REASONS
,
528 #endif /* _LINUX_MM_TYPES_H */