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)
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 */
67 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
68 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
69 /* Used for cmpxchg_double in slub */
70 unsigned long counters;
73 * Keep _count separate from slub cmpxchg_double data.
74 * As the rest of the double word is protected by
75 * slab_lock but _count is not.
84 * Count of ptes mapped in
85 * mms, to show when page is
86 * mapped & limit reverse map
89 * Used also for tail pages
90 * refcounting instead of
91 * _count. Tail pages cannot
92 * be mapped and keeping the
93 * tail page _count zero at
94 * all times guarantees
95 * get_page_unless_zero() will
96 * never succeed on tail
106 int units; /* SLOB */
108 atomic_t _count; /* Usage count, see below. */
110 unsigned int active; /* SLAB */
115 * Third double word block
117 * WARNING: bit 0 of the first word encode PageTail(). That means
118 * the rest users of the storage space MUST NOT use the bit to
119 * avoid collision and false-positive PageTail().
122 struct list_head lru; /* Pageout list, eg. active_list
123 * protected by zone->lru_lock !
124 * Can be used as a generic list
127 struct { /* slub per cpu partial pages */
128 struct page *next; /* Next partial slab */
130 int pages; /* Nr of partial slabs left */
131 int pobjects; /* Approximate # of objects */
138 struct rcu_head rcu_head; /* Used by SLAB
139 * when destroying via RCU
141 /* Tail pages of compound page */
143 unsigned long compound_head; /* If bit zero is set */
145 /* First tail page only */
148 * On 64 bit system we have enough space in struct page
149 * to encode compound_dtor and compound_order with
150 * unsigned int. It can help compiler generate better or
151 * smaller code on some archtectures.
153 unsigned int compound_dtor;
154 unsigned int compound_order;
156 unsigned short int compound_dtor;
157 unsigned short int compound_order;
161 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
163 unsigned long __pad; /* do not overlay pmd_huge_pte
164 * with compound_head to avoid
165 * possible bit 0 collision.
167 pgtable_t pmd_huge_pte; /* protected by page->ptl */
172 /* Remainder is not double word aligned */
174 unsigned long private; /* Mapping-private opaque data:
175 * usually used for buffer_heads
176 * if PagePrivate set; used for
177 * swp_entry_t if PageSwapCache;
178 * indicates order in the buddy
179 * system if PG_buddy is set.
181 #if USE_SPLIT_PTE_PTLOCKS
182 #if ALLOC_SPLIT_PTLOCKS
188 struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */
192 struct mem_cgroup *mem_cgroup;
196 * On machines where all RAM is mapped into kernel address space,
197 * we can simply calculate the virtual address. On machines with
198 * highmem some memory is mapped into kernel virtual memory
199 * dynamically, so we need a place to store that address.
200 * Note that this field could be 16 bits on x86 ... ;)
202 * Architectures with slow multiplication can define
203 * WANT_PAGE_VIRTUAL in asm/page.h
205 #if defined(WANT_PAGE_VIRTUAL)
206 void *virtual; /* Kernel virtual address (NULL if
207 not kmapped, ie. highmem) */
208 #endif /* WANT_PAGE_VIRTUAL */
210 #ifdef CONFIG_KMEMCHECK
212 * kmemcheck wants to track the status of each byte in a page; this
213 * is a pointer to such a status block. NULL if not tracked.
218 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
223 * The struct page can be forced to be double word aligned so that atomic ops
224 * on double words work. The SLUB allocator can make use of such a feature.
226 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
227 __aligned(2 * sizeof(unsigned long))
233 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
242 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
243 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
245 struct page_frag_cache {
247 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
253 /* we maintain a pagecount bias, so that we dont dirty cache line
254 * containing page->_count every time we allocate a fragment.
256 unsigned int pagecnt_bias;
260 typedef unsigned long vm_flags_t;
263 * A region containing a mapping of a non-memory backed file under NOMMU
264 * conditions. These are held in a global tree and are pinned by the VMAs that
268 struct rb_node vm_rb; /* link in global region tree */
269 vm_flags_t vm_flags; /* VMA vm_flags */
270 unsigned long vm_start; /* start address of region */
271 unsigned long vm_end; /* region initialised to here */
272 unsigned long vm_top; /* region allocated to here */
273 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
274 struct file *vm_file; /* the backing file or NULL */
276 int vm_usage; /* region usage count (access under nommu_region_sem) */
277 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
281 #ifdef CONFIG_USERFAULTFD
282 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
283 struct vm_userfaultfd_ctx {
284 struct userfaultfd_ctx *ctx;
286 #else /* CONFIG_USERFAULTFD */
287 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
288 struct vm_userfaultfd_ctx {};
289 #endif /* CONFIG_USERFAULTFD */
292 * This struct defines a memory VMM memory area. There is one of these
293 * per VM-area/task. A VM area is any part of the process virtual memory
294 * space that has a special rule for the page-fault handlers (ie a shared
295 * library, the executable area etc).
297 struct vm_area_struct {
298 /* The first cache line has the info for VMA tree walking. */
300 unsigned long vm_start; /* Our start address within vm_mm. */
301 unsigned long vm_end; /* The first byte after our end address
304 /* linked list of VM areas per task, sorted by address */
305 struct vm_area_struct *vm_next, *vm_prev;
307 struct rb_node vm_rb;
310 * Largest free memory gap in bytes to the left of this VMA.
311 * Either between this VMA and vma->vm_prev, or between one of the
312 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
313 * get_unmapped_area find a free area of the right size.
315 unsigned long rb_subtree_gap;
317 /* Second cache line starts here. */
319 struct mm_struct *vm_mm; /* The address space we belong to. */
320 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
321 unsigned long vm_flags; /* Flags, see mm.h. */
324 * For areas with an address space and backing store,
325 * linkage into the address_space->i_mmap interval tree.
329 unsigned long rb_subtree_last;
333 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
334 * list, after a COW of one of the file pages. A MAP_SHARED vma
335 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
336 * or brk vma (with NULL file) can only be in an anon_vma list.
338 struct list_head anon_vma_chain; /* Serialized by mmap_sem &
340 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
342 /* Function pointers to deal with this struct. */
343 const struct vm_operations_struct *vm_ops;
345 /* Information about our backing store: */
346 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
347 units, *not* PAGE_CACHE_SIZE */
348 struct file * vm_file; /* File we map to (can be NULL). */
349 void * vm_private_data; /* was vm_pte (shared mem) */
352 struct vm_region *vm_region; /* NOMMU mapping region */
355 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
357 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
361 struct task_struct *task;
362 struct core_thread *next;
367 struct core_thread dumper;
368 struct completion startup;
378 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
379 #define SPLIT_RSS_COUNTING
380 /* per-thread cached information, */
381 struct task_rss_stat {
382 int events; /* for synchronization threshold */
383 int count[NR_MM_COUNTERS];
385 #endif /* USE_SPLIT_PTE_PTLOCKS */
388 atomic_long_t count[NR_MM_COUNTERS];
393 struct vm_area_struct *mmap; /* list of VMAs */
394 struct rb_root mm_rb;
395 u32 vmacache_seqnum; /* per-thread vmacache */
397 unsigned long (*get_unmapped_area) (struct file *filp,
398 unsigned long addr, unsigned long len,
399 unsigned long pgoff, unsigned long flags);
401 unsigned long mmap_base; /* base of mmap area */
402 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
403 unsigned long task_size; /* size of task vm space */
404 unsigned long highest_vm_end; /* highest vma end address */
406 atomic_t mm_users; /* How many users with user space? */
407 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
408 atomic_long_t nr_ptes; /* PTE page table pages */
409 #if CONFIG_PGTABLE_LEVELS > 2
410 atomic_long_t nr_pmds; /* PMD page table pages */
412 int map_count; /* number of VMAs */
414 spinlock_t page_table_lock; /* Protects page tables and some counters */
415 struct rw_semaphore mmap_sem;
417 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
418 * together off init_mm.mmlist, and are protected
423 unsigned long hiwater_rss; /* High-watermark of RSS usage */
424 unsigned long hiwater_vm; /* High-water virtual memory usage */
426 unsigned long total_vm; /* Total pages mapped */
427 unsigned long locked_vm; /* Pages that have PG_mlocked set */
428 unsigned long pinned_vm; /* Refcount permanently increased */
429 unsigned long shared_vm; /* Shared pages (files) */
430 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */
431 unsigned long stack_vm; /* VM_GROWSUP/DOWN */
432 unsigned long def_flags;
433 unsigned long start_code, end_code, start_data, end_data;
434 unsigned long start_brk, brk, start_stack;
435 unsigned long arg_start, arg_end, env_start, env_end;
437 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
440 * Special counters, in some configurations protected by the
441 * page_table_lock, in other configurations by being atomic.
443 struct mm_rss_stat rss_stat;
445 struct linux_binfmt *binfmt;
447 cpumask_var_t cpu_vm_mask_var;
449 /* Architecture-specific MM context */
450 mm_context_t context;
452 unsigned long flags; /* Must use atomic bitops to access the bits */
454 struct core_state *core_state; /* coredumping support */
456 spinlock_t ioctx_lock;
457 struct kioctx_table __rcu *ioctx_table;
461 * "owner" points to a task that is regarded as the canonical
462 * user/owner of this mm. All of the following must be true in
463 * order for it to be changed:
465 * current == mm->owner
467 * new_owner->mm == mm
468 * new_owner->alloc_lock is held
470 struct task_struct __rcu *owner;
473 /* store ref to file /proc/<pid>/exe symlink points to */
474 struct file __rcu *exe_file;
475 #ifdef CONFIG_MMU_NOTIFIER
476 struct mmu_notifier_mm *mmu_notifier_mm;
478 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
479 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
481 #ifdef CONFIG_CPUMASK_OFFSTACK
482 struct cpumask cpumask_allocation;
484 #ifdef CONFIG_NUMA_BALANCING
486 * numa_next_scan is the next time that the PTEs will be marked
487 * pte_numa. NUMA hinting faults will gather statistics and migrate
488 * pages to new nodes if necessary.
490 unsigned long numa_next_scan;
492 /* Restart point for scanning and setting pte_numa */
493 unsigned long numa_scan_offset;
495 /* numa_scan_seq prevents two threads setting pte_numa */
498 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
500 * An operation with batched TLB flushing is going on. Anything that
501 * can move process memory needs to flush the TLB when moving a
502 * PROT_NONE or PROT_NUMA mapped page.
504 bool tlb_flush_pending;
506 struct uprobes_state uprobes_state;
507 #ifdef CONFIG_X86_INTEL_MPX
508 /* address of the bounds directory */
509 void __user *bd_addr;
511 #ifdef CONFIG_HUGETLB_PAGE
512 atomic_long_t hugetlb_usage;
516 static inline void mm_init_cpumask(struct mm_struct *mm)
518 #ifdef CONFIG_CPUMASK_OFFSTACK
519 mm->cpu_vm_mask_var = &mm->cpumask_allocation;
521 cpumask_clear(mm->cpu_vm_mask_var);
524 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
525 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
527 return mm->cpu_vm_mask_var;
530 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
532 * Memory barriers to keep this state in sync are graciously provided by
533 * the page table locks, outside of which no page table modifications happen.
534 * The barriers below prevent the compiler from re-ordering the instructions
535 * around the memory barriers that are already present in the code.
537 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
540 return mm->tlb_flush_pending;
542 static inline void set_tlb_flush_pending(struct mm_struct *mm)
544 mm->tlb_flush_pending = true;
547 * Guarantee that the tlb_flush_pending store does not leak into the
548 * critical section updating the page tables
550 smp_mb__before_spinlock();
552 /* Clearing is done after a TLB flush, which also provides a barrier. */
553 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
556 mm->tlb_flush_pending = false;
559 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
563 static inline void set_tlb_flush_pending(struct mm_struct *mm)
566 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
571 struct vm_special_mapping
577 enum tlb_flush_reason {
578 TLB_FLUSH_ON_TASK_SWITCH,
579 TLB_REMOTE_SHOOTDOWN,
581 TLB_LOCAL_MM_SHOOTDOWN,
583 NR_TLB_FLUSH_REASONS,
587 * A swap entry has to fit into a "unsigned long", as the entry is hidden
588 * in the "index" field of the swapper address space.
594 #endif /* _LINUX_MM_TYPES_H */