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 */
66 bool pfmemalloc; /* If set by the page allocator,
67 * ALLOC_NO_WATERMARKS was set
68 * and the low watermark was not
69 * met implying that the system
70 * is under some pressure. The
71 * caller should try ensure
72 * this page is only used to
78 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
79 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
80 /* Used for cmpxchg_double in slub */
81 unsigned long counters;
84 * Keep _count separate from slub cmpxchg_double data.
85 * As the rest of the double word is protected by
86 * slab_lock but _count is not.
95 * Count of ptes mapped in
96 * mms, to show when page is
97 * mapped & limit reverse map
100 * Used also for tail pages
101 * refcounting instead of
102 * _count. Tail pages cannot
103 * be mapped and keeping the
104 * tail page _count zero at
105 * all times guarantees
106 * get_page_unless_zero() will
107 * never succeed on tail
117 int units; /* SLOB */
119 atomic_t _count; /* Usage count, see below. */
121 unsigned int active; /* SLAB */
125 /* Third double word block */
127 struct list_head lru; /* Pageout list, eg. active_list
128 * protected by zone->lru_lock !
129 * Can be used as a generic list
132 struct { /* slub per cpu partial pages */
133 struct page *next; /* Next partial slab */
135 int pages; /* Nr of partial slabs left */
136 int pobjects; /* Approximate # of objects */
143 struct slab *slab_page; /* slab fields */
144 struct rcu_head rcu_head; /* Used by SLAB
145 * when destroying via RCU
147 /* First tail page of compound page */
149 compound_page_dtor *compound_dtor;
150 unsigned long compound_order;
153 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
154 pgtable_t pmd_huge_pte; /* protected by page->ptl */
158 /* Remainder is not double word aligned */
160 unsigned long private; /* Mapping-private opaque data:
161 * usually used for buffer_heads
162 * if PagePrivate set; used for
163 * swp_entry_t if PageSwapCache;
164 * indicates order in the buddy
165 * system if PG_buddy is set.
167 #if USE_SPLIT_PTE_PTLOCKS
168 #if ALLOC_SPLIT_PTLOCKS
174 struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */
175 struct page *first_page; /* Compound tail pages */
179 struct mem_cgroup *mem_cgroup;
183 * On machines where all RAM is mapped into kernel address space,
184 * we can simply calculate the virtual address. On machines with
185 * highmem some memory is mapped into kernel virtual memory
186 * dynamically, so we need a place to store that address.
187 * Note that this field could be 16 bits on x86 ... ;)
189 * Architectures with slow multiplication can define
190 * WANT_PAGE_VIRTUAL in asm/page.h
192 #if defined(WANT_PAGE_VIRTUAL)
193 void *virtual; /* Kernel virtual address (NULL if
194 not kmapped, ie. highmem) */
195 #endif /* WANT_PAGE_VIRTUAL */
197 #ifdef CONFIG_KMEMCHECK
199 * kmemcheck wants to track the status of each byte in a page; this
200 * is a pointer to such a status block. NULL if not tracked.
205 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
210 * The struct page can be forced to be double word aligned so that atomic ops
211 * on double words work. The SLUB allocator can make use of such a feature.
213 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
214 __aligned(2 * sizeof(unsigned long))
220 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
229 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
230 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
232 struct page_frag_cache {
234 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
240 /* we maintain a pagecount bias, so that we dont dirty cache line
241 * containing page->_count every time we allocate a fragment.
243 unsigned int pagecnt_bias;
247 typedef unsigned long __nocast vm_flags_t;
250 * A region containing a mapping of a non-memory backed file under NOMMU
251 * conditions. These are held in a global tree and are pinned by the VMAs that
255 struct rb_node vm_rb; /* link in global region tree */
256 vm_flags_t vm_flags; /* VMA vm_flags */
257 unsigned long vm_start; /* start address of region */
258 unsigned long vm_end; /* region initialised to here */
259 unsigned long vm_top; /* region allocated to here */
260 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
261 struct file *vm_file; /* the backing file or NULL */
263 int vm_usage; /* region usage count (access under nommu_region_sem) */
264 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
269 * This struct defines a memory VMM memory area. There is one of these
270 * per VM-area/task. A VM area is any part of the process virtual memory
271 * space that has a special rule for the page-fault handlers (ie a shared
272 * library, the executable area etc).
274 struct vm_area_struct {
275 /* The first cache line has the info for VMA tree walking. */
277 unsigned long vm_start; /* Our start address within vm_mm. */
278 unsigned long vm_end; /* The first byte after our end address
281 /* linked list of VM areas per task, sorted by address */
282 struct vm_area_struct *vm_next, *vm_prev;
284 struct rb_node vm_rb;
287 * Largest free memory gap in bytes to the left of this VMA.
288 * Either between this VMA and vma->vm_prev, or between one of the
289 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
290 * get_unmapped_area find a free area of the right size.
292 unsigned long rb_subtree_gap;
294 /* Second cache line starts here. */
296 struct mm_struct *vm_mm; /* The address space we belong to. */
297 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
298 unsigned long vm_flags; /* Flags, see mm.h. */
301 * For areas with an address space and backing store,
302 * linkage into the address_space->i_mmap interval tree.
306 unsigned long rb_subtree_last;
310 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
311 * list, after a COW of one of the file pages. A MAP_SHARED vma
312 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
313 * or brk vma (with NULL file) can only be in an anon_vma list.
315 struct list_head anon_vma_chain; /* Serialized by mmap_sem &
317 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
319 /* Function pointers to deal with this struct. */
320 const struct vm_operations_struct *vm_ops;
322 /* Information about our backing store: */
323 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
324 units, *not* PAGE_CACHE_SIZE */
325 struct file * vm_file; /* File we map to (can be NULL). */
326 void * vm_private_data; /* was vm_pte (shared mem) */
329 struct vm_region *vm_region; /* NOMMU mapping region */
332 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
337 struct task_struct *task;
338 struct core_thread *next;
343 struct core_thread dumper;
344 struct completion startup;
354 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
355 #define SPLIT_RSS_COUNTING
356 /* per-thread cached information, */
357 struct task_rss_stat {
358 int events; /* for synchronization threshold */
359 int count[NR_MM_COUNTERS];
361 #endif /* USE_SPLIT_PTE_PTLOCKS */
364 atomic_long_t count[NR_MM_COUNTERS];
369 struct vm_area_struct *mmap; /* list of VMAs */
370 struct rb_root mm_rb;
371 u32 vmacache_seqnum; /* per-thread vmacache */
373 unsigned long (*get_unmapped_area) (struct file *filp,
374 unsigned long addr, unsigned long len,
375 unsigned long pgoff, unsigned long flags);
377 unsigned long mmap_base; /* base of mmap area */
378 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
379 unsigned long task_size; /* size of task vm space */
380 unsigned long highest_vm_end; /* highest vma end address */
382 atomic_t mm_users; /* How many users with user space? */
383 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
384 atomic_long_t nr_ptes; /* PTE page table pages */
385 #if CONFIG_PGTABLE_LEVELS > 2
386 atomic_long_t nr_pmds; /* PMD page table pages */
388 int map_count; /* number of VMAs */
390 spinlock_t page_table_lock; /* Protects page tables and some counters */
391 struct rw_semaphore mmap_sem;
393 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
394 * together off init_mm.mmlist, and are protected
399 unsigned long hiwater_rss; /* High-watermark of RSS usage */
400 unsigned long hiwater_vm; /* High-water virtual memory usage */
402 unsigned long total_vm; /* Total pages mapped */
403 unsigned long locked_vm; /* Pages that have PG_mlocked set */
404 unsigned long pinned_vm; /* Refcount permanently increased */
405 unsigned long shared_vm; /* Shared pages (files) */
406 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */
407 unsigned long stack_vm; /* VM_GROWSUP/DOWN */
408 unsigned long def_flags;
409 unsigned long start_code, end_code, start_data, end_data;
410 unsigned long start_brk, brk, start_stack;
411 unsigned long arg_start, arg_end, env_start, env_end;
413 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
416 * Special counters, in some configurations protected by the
417 * page_table_lock, in other configurations by being atomic.
419 struct mm_rss_stat rss_stat;
421 struct linux_binfmt *binfmt;
423 cpumask_var_t cpu_vm_mask_var;
425 /* Architecture-specific MM context */
426 mm_context_t context;
428 unsigned long flags; /* Must use atomic bitops to access the bits */
430 struct core_state *core_state; /* coredumping support */
432 spinlock_t ioctx_lock;
433 struct kioctx_table __rcu *ioctx_table;
437 * "owner" points to a task that is regarded as the canonical
438 * user/owner of this mm. All of the following must be true in
439 * order for it to be changed:
441 * current == mm->owner
443 * new_owner->mm == mm
444 * new_owner->alloc_lock is held
446 struct task_struct __rcu *owner;
449 /* store ref to file /proc/<pid>/exe symlink points to */
450 struct file __rcu *exe_file;
451 #ifdef CONFIG_MMU_NOTIFIER
452 struct mmu_notifier_mm *mmu_notifier_mm;
454 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
455 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
457 #ifdef CONFIG_CPUMASK_OFFSTACK
458 struct cpumask cpumask_allocation;
460 #ifdef CONFIG_NUMA_BALANCING
462 * numa_next_scan is the next time that the PTEs will be marked
463 * pte_numa. NUMA hinting faults will gather statistics and migrate
464 * pages to new nodes if necessary.
466 unsigned long numa_next_scan;
468 /* Restart point for scanning and setting pte_numa */
469 unsigned long numa_scan_offset;
471 /* numa_scan_seq prevents two threads setting pte_numa */
474 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
476 * An operation with batched TLB flushing is going on. Anything that
477 * can move process memory needs to flush the TLB when moving a
478 * PROT_NONE or PROT_NUMA mapped page.
480 bool tlb_flush_pending;
482 struct uprobes_state uprobes_state;
483 #ifdef CONFIG_X86_INTEL_MPX
484 /* address of the bounds directory */
485 void __user *bd_addr;
489 static inline void mm_init_cpumask(struct mm_struct *mm)
491 #ifdef CONFIG_CPUMASK_OFFSTACK
492 mm->cpu_vm_mask_var = &mm->cpumask_allocation;
494 cpumask_clear(mm->cpu_vm_mask_var);
497 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
498 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
500 return mm->cpu_vm_mask_var;
503 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
505 * Memory barriers to keep this state in sync are graciously provided by
506 * the page table locks, outside of which no page table modifications happen.
507 * The barriers below prevent the compiler from re-ordering the instructions
508 * around the memory barriers that are already present in the code.
510 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
513 return mm->tlb_flush_pending;
515 static inline void set_tlb_flush_pending(struct mm_struct *mm)
517 mm->tlb_flush_pending = true;
520 * Guarantee that the tlb_flush_pending store does not leak into the
521 * critical section updating the page tables
523 smp_mb__before_spinlock();
525 /* Clearing is done after a TLB flush, which also provides a barrier. */
526 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
529 mm->tlb_flush_pending = false;
532 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
536 static inline void set_tlb_flush_pending(struct mm_struct *mm)
539 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
544 struct vm_special_mapping
550 enum tlb_flush_reason {
551 TLB_FLUSH_ON_TASK_SWITCH,
552 TLB_REMOTE_SHOOTDOWN,
554 TLB_LOCAL_MM_SHOOTDOWN,
555 NR_TLB_FLUSH_REASONS,
559 * A swap entry has to fit into a "unsigned long", as the entry is hidden
560 * in the "index" field of the swapper address space.
566 #endif /* _LINUX_MM_TYPES_H */