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/rcupdate.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))
27 #define USE_SPLIT_PTE_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
28 #define USE_SPLIT_PMD_PTLOCKS (USE_SPLIT_PTE_PTLOCKS && \
29 IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
30 #define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)
33 * Each physical page in the system has a struct page associated with
34 * it to keep track of whatever it is we are using the page for at the
35 * moment. Note that we have no way to track which tasks are using
36 * a page, though if it is a pagecache page, rmap structures can tell us
39 * The objects in struct page are organized in double word blocks in
40 * order to allows us to use atomic double word operations on portions
41 * of struct page. That is currently only used by slub but the arrangement
42 * allows the use of atomic double word operations on the flags/mapping
43 * and lru list pointers also.
46 /* First double word block */
47 unsigned long flags; /* Atomic flags, some possibly
48 * updated asynchronously */
50 struct address_space *mapping; /* If low bit clear, points to
51 * inode address_space, or NULL.
52 * If page mapped as anonymous
53 * memory, low bit is set, and
54 * it points to anon_vma object:
55 * see PAGE_MAPPING_ANON below.
57 void *s_mem; /* slab first object */
60 /* Second double word */
63 pgoff_t index; /* Our offset within mapping. */
64 void *freelist; /* sl[aou]b first free object */
68 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
69 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
70 /* Used for cmpxchg_double in slub */
71 unsigned long counters;
74 * Keep _count separate from slub cmpxchg_double data.
75 * As the rest of the double word is protected by
76 * slab_lock but _count is not.
85 * Count of ptes mapped in
86 * mms, to show when page is
87 * mapped & limit reverse map
90 * Used also for tail pages
91 * refcounting instead of
92 * _count. Tail pages cannot
93 * be mapped and keeping the
94 * tail page _count zero at
95 * all times guarantees
96 * get_page_unless_zero() will
97 * never succeed on tail
107 int units; /* SLOB */
109 atomic_t _count; /* Usage count, see below. */
111 unsigned int active; /* SLAB */
116 * Third double word block
118 * WARNING: bit 0 of the first word encode PageTail(). That means
119 * the rest users of the storage space MUST NOT use the bit to
120 * avoid collision and false-positive PageTail().
123 struct list_head lru; /* Pageout list, eg. active_list
124 * protected by zone->lru_lock !
125 * Can be used as a generic list
128 struct { /* slub per cpu partial pages */
129 struct page *next; /* Next partial slab */
131 int pages; /* Nr of partial slabs left */
132 int pobjects; /* Approximate # of objects */
139 struct rcu_head rcu_head; /* Used by SLAB
140 * when destroying via RCU
142 /* Tail pages of compound page */
144 unsigned long compound_head; /* If bit zero is set */
146 /* First tail page only */
149 * On 64 bit system we have enough space in struct page
150 * to encode compound_dtor and compound_order with
151 * unsigned int. It can help compiler generate better or
152 * smaller code on some archtectures.
154 unsigned int compound_dtor;
155 unsigned int compound_order;
157 unsigned short int compound_dtor;
158 unsigned short int compound_order;
162 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
164 unsigned long __pad; /* do not overlay pmd_huge_pte
165 * with compound_head to avoid
166 * possible bit 0 collision.
168 pgtable_t pmd_huge_pte; /* protected by page->ptl */
173 /* Remainder is not double word aligned */
175 unsigned long private; /* Mapping-private opaque data:
176 * usually used for buffer_heads
177 * if PagePrivate set; used for
178 * swp_entry_t if PageSwapCache;
179 * indicates order in the buddy
180 * system if PG_buddy is set.
182 #if USE_SPLIT_PTE_PTLOCKS
183 #if ALLOC_SPLIT_PTLOCKS
189 struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */
193 struct mem_cgroup *mem_cgroup;
197 * On machines where all RAM is mapped into kernel address space,
198 * we can simply calculate the virtual address. On machines with
199 * highmem some memory is mapped into kernel virtual memory
200 * dynamically, so we need a place to store that address.
201 * Note that this field could be 16 bits on x86 ... ;)
203 * Architectures with slow multiplication can define
204 * WANT_PAGE_VIRTUAL in asm/page.h
206 #if defined(WANT_PAGE_VIRTUAL)
207 void *virtual; /* Kernel virtual address (NULL if
208 not kmapped, ie. highmem) */
209 #endif /* WANT_PAGE_VIRTUAL */
211 #ifdef CONFIG_KMEMCHECK
213 * kmemcheck wants to track the status of each byte in a page; this
214 * is a pointer to such a status block. NULL if not tracked.
219 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
224 * The struct page can be forced to be double word aligned so that atomic ops
225 * on double words work. The SLUB allocator can make use of such a feature.
227 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
228 __aligned(2 * sizeof(unsigned long))
234 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
243 #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
244 #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
246 struct page_frag_cache {
248 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
254 /* we maintain a pagecount bias, so that we dont dirty cache line
255 * containing page->_count every time we allocate a fragment.
257 unsigned int pagecnt_bias;
261 typedef unsigned long vm_flags_t;
264 * A region containing a mapping of a non-memory backed file under NOMMU
265 * conditions. These are held in a global tree and are pinned by the VMAs that
269 struct rb_node vm_rb; /* link in global region tree */
270 vm_flags_t vm_flags; /* VMA vm_flags */
271 unsigned long vm_start; /* start address of region */
272 unsigned long vm_end; /* region initialised to here */
273 unsigned long vm_top; /* region allocated to here */
274 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
275 struct file *vm_file; /* the backing file or NULL */
277 int vm_usage; /* region usage count (access under nommu_region_sem) */
278 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
282 #ifdef CONFIG_USERFAULTFD
283 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) { NULL, })
284 struct vm_userfaultfd_ctx {
285 struct userfaultfd_ctx *ctx;
287 #else /* CONFIG_USERFAULTFD */
288 #define NULL_VM_UFFD_CTX ((struct vm_userfaultfd_ctx) {})
289 struct vm_userfaultfd_ctx {};
290 #endif /* CONFIG_USERFAULTFD */
293 * This struct defines a memory VMM memory area. There is one of these
294 * per VM-area/task. A VM area is any part of the process virtual memory
295 * space that has a special rule for the page-fault handlers (ie a shared
296 * library, the executable area etc).
298 struct vm_area_struct {
299 /* The first cache line has the info for VMA tree walking. */
301 unsigned long vm_start; /* Our start address within vm_mm. */
302 unsigned long vm_end; /* The first byte after our end address
305 /* linked list of VM areas per task, sorted by address */
306 struct vm_area_struct *vm_next, *vm_prev;
308 struct rb_node vm_rb;
311 * Largest free memory gap in bytes to the left of this VMA.
312 * Either between this VMA and vma->vm_prev, or between one of the
313 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
314 * get_unmapped_area find a free area of the right size.
316 unsigned long rb_subtree_gap;
318 /* Second cache line starts here. */
320 struct mm_struct *vm_mm; /* The address space we belong to. */
321 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
322 unsigned long vm_flags; /* Flags, see mm.h. */
325 * For areas with an address space and backing store,
326 * linkage into the address_space->i_mmap interval tree.
330 unsigned long rb_subtree_last;
334 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
335 * list, after a COW of one of the file pages. A MAP_SHARED vma
336 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
337 * or brk vma (with NULL file) can only be in an anon_vma list.
339 struct list_head anon_vma_chain; /* Serialized by mmap_sem &
341 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
343 /* Function pointers to deal with this struct. */
344 const struct vm_operations_struct *vm_ops;
346 /* Information about our backing store: */
347 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
348 units, *not* PAGE_CACHE_SIZE */
349 struct file * vm_file; /* File we map to (can be NULL). */
350 void * vm_private_data; /* was vm_pte (shared mem) */
353 struct vm_region *vm_region; /* NOMMU mapping region */
356 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
358 struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
362 struct task_struct *task;
363 struct core_thread *next;
368 struct core_thread dumper;
369 struct completion startup;
379 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
380 #define SPLIT_RSS_COUNTING
381 /* per-thread cached information, */
382 struct task_rss_stat {
383 int events; /* for synchronization threshold */
384 int count[NR_MM_COUNTERS];
386 #endif /* USE_SPLIT_PTE_PTLOCKS */
389 atomic_long_t count[NR_MM_COUNTERS];
394 struct vm_area_struct *mmap; /* list of VMAs */
395 struct rb_root mm_rb;
396 u32 vmacache_seqnum; /* per-thread vmacache */
398 unsigned long (*get_unmapped_area) (struct file *filp,
399 unsigned long addr, unsigned long len,
400 unsigned long pgoff, unsigned long flags);
402 unsigned long mmap_base; /* base of mmap area */
403 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
404 unsigned long task_size; /* size of task vm space */
405 unsigned long highest_vm_end; /* highest vma end address */
407 atomic_t mm_users; /* How many users with user space? */
408 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
409 atomic_long_t nr_ptes; /* PTE page table pages */
410 #if CONFIG_PGTABLE_LEVELS > 2
411 atomic_long_t nr_pmds; /* PMD page table pages */
413 int map_count; /* number of VMAs */
415 spinlock_t page_table_lock; /* Protects page tables and some counters */
416 struct rw_semaphore mmap_sem;
418 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
419 * together off init_mm.mmlist, and are protected
424 unsigned long hiwater_rss; /* High-watermark of RSS usage */
425 unsigned long hiwater_vm; /* High-water virtual memory usage */
427 unsigned long total_vm; /* Total pages mapped */
428 unsigned long locked_vm; /* Pages that have PG_mlocked set */
429 unsigned long pinned_vm; /* Refcount permanently increased */
430 unsigned long shared_vm; /* Shared pages (files) */
431 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */
432 unsigned long stack_vm; /* VM_GROWSUP/DOWN */
433 unsigned long def_flags;
434 unsigned long start_code, end_code, start_data, end_data;
435 unsigned long start_brk, brk, start_stack;
436 unsigned long arg_start, arg_end, env_start, env_end;
438 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
441 * Special counters, in some configurations protected by the
442 * page_table_lock, in other configurations by being atomic.
444 struct mm_rss_stat rss_stat;
446 struct linux_binfmt *binfmt;
448 cpumask_var_t cpu_vm_mask_var;
450 /* Architecture-specific MM context */
451 mm_context_t context;
453 unsigned long flags; /* Must use atomic bitops to access the bits */
455 struct core_state *core_state; /* coredumping support */
457 spinlock_t ioctx_lock;
458 struct kioctx_table __rcu *ioctx_table;
462 * "owner" points to a task that is regarded as the canonical
463 * user/owner of this mm. All of the following must be true in
464 * order for it to be changed:
466 * current == mm->owner
468 * new_owner->mm == mm
469 * new_owner->alloc_lock is held
471 struct task_struct __rcu *owner;
474 /* store ref to file /proc/<pid>/exe symlink points to */
475 struct file __rcu *exe_file;
476 #ifdef CONFIG_MMU_NOTIFIER
477 struct mmu_notifier_mm *mmu_notifier_mm;
479 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
480 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
482 #ifdef CONFIG_CPUMASK_OFFSTACK
483 struct cpumask cpumask_allocation;
485 #ifdef CONFIG_NUMA_BALANCING
487 * numa_next_scan is the next time that the PTEs will be marked
488 * pte_numa. NUMA hinting faults will gather statistics and migrate
489 * pages to new nodes if necessary.
491 unsigned long numa_next_scan;
493 /* Restart point for scanning and setting pte_numa */
494 unsigned long numa_scan_offset;
496 /* numa_scan_seq prevents two threads setting pte_numa */
499 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
501 * An operation with batched TLB flushing is going on. Anything that
502 * can move process memory needs to flush the TLB when moving a
503 * PROT_NONE or PROT_NUMA mapped page.
505 bool tlb_flush_pending;
507 struct uprobes_state uprobes_state;
508 #ifdef CONFIG_PREEMPT_RT_BASE
509 struct rcu_head delayed_drop;
511 #ifdef CONFIG_X86_INTEL_MPX
512 /* address of the bounds directory */
513 void __user *bd_addr;
515 #ifdef CONFIG_HUGETLB_PAGE
516 atomic_long_t hugetlb_usage;
520 static inline void mm_init_cpumask(struct mm_struct *mm)
522 #ifdef CONFIG_CPUMASK_OFFSTACK
523 mm->cpu_vm_mask_var = &mm->cpumask_allocation;
525 cpumask_clear(mm->cpu_vm_mask_var);
528 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
529 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
531 return mm->cpu_vm_mask_var;
534 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
536 * Memory barriers to keep this state in sync are graciously provided by
537 * the page table locks, outside of which no page table modifications happen.
538 * The barriers below prevent the compiler from re-ordering the instructions
539 * around the memory barriers that are already present in the code.
541 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
544 return mm->tlb_flush_pending;
546 static inline void set_tlb_flush_pending(struct mm_struct *mm)
548 mm->tlb_flush_pending = true;
551 * Guarantee that the tlb_flush_pending store does not leak into the
552 * critical section updating the page tables
554 smp_mb__before_spinlock();
556 /* Clearing is done after a TLB flush, which also provides a barrier. */
557 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
560 mm->tlb_flush_pending = false;
563 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
567 static inline void set_tlb_flush_pending(struct mm_struct *mm)
570 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
575 struct vm_special_mapping
581 enum tlb_flush_reason {
582 TLB_FLUSH_ON_TASK_SWITCH,
583 TLB_REMOTE_SHOOTDOWN,
585 TLB_LOCAL_MM_SHOOTDOWN,
587 NR_TLB_FLUSH_REASONS,
591 * A swap entry has to fit into a "unsigned long", as the entry is hidden
592 * in the "index" field of the swapper address space.
598 #endif /* _LINUX_MM_TYPES_H */