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))
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 */
65 bool pfmemalloc; /* If set by the page allocator,
66 * ALLOC_NO_WATERMARKS was set
67 * and the low watermark was not
68 * met implying that the system
69 * is under some pressure. The
70 * caller should try ensure
71 * this page is only used to
77 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
78 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
79 /* Used for cmpxchg_double in slub */
80 unsigned long counters;
83 * Keep _count separate from slub cmpxchg_double data.
84 * As the rest of the double word is protected by
85 * slab_lock but _count is not.
94 * Count of ptes mapped in
95 * mms, to show when page is
96 * mapped & limit reverse map
99 * Used also for tail pages
100 * refcounting instead of
101 * _count. Tail pages cannot
102 * be mapped and keeping the
103 * tail page _count zero at
104 * all times guarantees
105 * get_page_unless_zero() will
106 * never succeed on tail
116 int units; /* SLOB */
118 atomic_t _count; /* Usage count, see below. */
120 unsigned int active; /* SLAB */
124 /* Third double word block */
126 struct list_head lru; /* Pageout list, eg. active_list
127 * protected by zone->lru_lock !
128 * Can be used as a generic list
131 struct { /* slub per cpu partial pages */
132 struct page *next; /* Next partial slab */
134 int pages; /* Nr of partial slabs left */
135 int pobjects; /* Approximate # of objects */
142 struct slab *slab_page; /* slab fields */
143 struct rcu_head rcu_head; /* Used by SLAB
144 * when destroying via RCU
146 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
147 pgtable_t pmd_huge_pte; /* protected by page->ptl */
151 /* Remainder is not double word aligned */
153 unsigned long private; /* Mapping-private opaque data:
154 * usually used for buffer_heads
155 * if PagePrivate set; used for
156 * swp_entry_t if PageSwapCache;
157 * indicates order in the buddy
158 * system if PG_buddy is set.
160 #if USE_SPLIT_PTE_PTLOCKS
161 #if ALLOC_SPLIT_PTLOCKS
167 struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */
168 struct page *first_page; /* Compound tail pages */
172 struct mem_cgroup *mem_cgroup;
176 * On machines where all RAM is mapped into kernel address space,
177 * we can simply calculate the virtual address. On machines with
178 * highmem some memory is mapped into kernel virtual memory
179 * dynamically, so we need a place to store that address.
180 * Note that this field could be 16 bits on x86 ... ;)
182 * Architectures with slow multiplication can define
183 * WANT_PAGE_VIRTUAL in asm/page.h
185 #if defined(WANT_PAGE_VIRTUAL)
186 void *virtual; /* Kernel virtual address (NULL if
187 not kmapped, ie. highmem) */
188 #endif /* WANT_PAGE_VIRTUAL */
189 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
190 unsigned long debug_flags; /* Use atomic bitops on this */
193 #ifdef CONFIG_KMEMCHECK
195 * kmemcheck wants to track the status of each byte in a page; this
196 * is a pointer to such a status block. NULL if not tracked.
201 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
206 * The struct page can be forced to be double word aligned so that atomic ops
207 * on double words work. The SLUB allocator can make use of such a feature.
209 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
210 __aligned(2 * sizeof(unsigned long))
216 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
225 typedef unsigned long __nocast vm_flags_t;
228 * A region containing a mapping of a non-memory backed file under NOMMU
229 * conditions. These are held in a global tree and are pinned by the VMAs that
233 struct rb_node vm_rb; /* link in global region tree */
234 vm_flags_t vm_flags; /* VMA vm_flags */
235 unsigned long vm_start; /* start address of region */
236 unsigned long vm_end; /* region initialised to here */
237 unsigned long vm_top; /* region allocated to here */
238 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
239 struct file *vm_file; /* the backing file or NULL */
241 int vm_usage; /* region usage count (access under nommu_region_sem) */
242 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
247 * This struct defines a memory VMM memory area. There is one of these
248 * per VM-area/task. A VM area is any part of the process virtual memory
249 * space that has a special rule for the page-fault handlers (ie a shared
250 * library, the executable area etc).
252 struct vm_area_struct {
253 /* The first cache line has the info for VMA tree walking. */
255 unsigned long vm_start; /* Our start address within vm_mm. */
256 unsigned long vm_end; /* The first byte after our end address
259 /* linked list of VM areas per task, sorted by address */
260 struct vm_area_struct *vm_next, *vm_prev;
262 struct rb_node vm_rb;
265 * Largest free memory gap in bytes to the left of this VMA.
266 * Either between this VMA and vma->vm_prev, or between one of the
267 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
268 * get_unmapped_area find a free area of the right size.
270 unsigned long rb_subtree_gap;
272 /* Second cache line starts here. */
274 struct mm_struct *vm_mm; /* The address space we belong to. */
275 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
276 unsigned long vm_flags; /* Flags, see mm.h. */
279 * For areas with an address space and backing store,
280 * linkage into the address_space->i_mmap interval tree, or
281 * linkage of vma in the address_space->i_mmap_nonlinear list.
286 unsigned long rb_subtree_last;
288 struct list_head nonlinear;
292 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
293 * list, after a COW of one of the file pages. A MAP_SHARED vma
294 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
295 * or brk vma (with NULL file) can only be in an anon_vma list.
297 struct list_head anon_vma_chain; /* Serialized by mmap_sem &
299 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
301 /* Function pointers to deal with this struct. */
302 const struct vm_operations_struct *vm_ops;
304 /* Information about our backing store: */
305 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
306 units, *not* PAGE_CACHE_SIZE */
307 struct file * vm_file; /* File we map to (can be NULL). */
308 void * vm_private_data; /* was vm_pte (shared mem) */
311 struct vm_region *vm_region; /* NOMMU mapping region */
314 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
319 struct task_struct *task;
320 struct core_thread *next;
325 struct core_thread dumper;
326 struct completion startup;
336 #if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
337 #define SPLIT_RSS_COUNTING
338 /* per-thread cached information, */
339 struct task_rss_stat {
340 int events; /* for synchronization threshold */
341 int count[NR_MM_COUNTERS];
343 #endif /* USE_SPLIT_PTE_PTLOCKS */
346 atomic_long_t count[NR_MM_COUNTERS];
351 struct vm_area_struct *mmap; /* list of VMAs */
352 struct rb_root mm_rb;
353 u32 vmacache_seqnum; /* per-thread vmacache */
355 unsigned long (*get_unmapped_area) (struct file *filp,
356 unsigned long addr, unsigned long len,
357 unsigned long pgoff, unsigned long flags);
359 unsigned long mmap_base; /* base of mmap area */
360 unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
361 unsigned long task_size; /* size of task vm space */
362 unsigned long highest_vm_end; /* highest vma end address */
364 atomic_t mm_users; /* How many users with user space? */
365 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
366 atomic_long_t nr_ptes; /* Page table pages */
367 int map_count; /* number of VMAs */
369 spinlock_t page_table_lock; /* Protects page tables and some counters */
370 struct rw_semaphore mmap_sem;
372 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
373 * together off init_mm.mmlist, and are protected
378 unsigned long hiwater_rss; /* High-watermark of RSS usage */
379 unsigned long hiwater_vm; /* High-water virtual memory usage */
381 unsigned long total_vm; /* Total pages mapped */
382 unsigned long locked_vm; /* Pages that have PG_mlocked set */
383 unsigned long pinned_vm; /* Refcount permanently increased */
384 unsigned long shared_vm; /* Shared pages (files) */
385 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */
386 unsigned long stack_vm; /* VM_GROWSUP/DOWN */
387 unsigned long def_flags;
388 unsigned long start_code, end_code, start_data, end_data;
389 unsigned long start_brk, brk, start_stack;
390 unsigned long arg_start, arg_end, env_start, env_end;
392 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
395 * Special counters, in some configurations protected by the
396 * page_table_lock, in other configurations by being atomic.
398 struct mm_rss_stat rss_stat;
400 struct linux_binfmt *binfmt;
402 cpumask_var_t cpu_vm_mask_var;
404 /* Architecture-specific MM context */
405 mm_context_t context;
407 unsigned long flags; /* Must use atomic bitops to access the bits */
409 struct core_state *core_state; /* coredumping support */
411 spinlock_t ioctx_lock;
412 struct kioctx_table __rcu *ioctx_table;
416 * "owner" points to a task that is regarded as the canonical
417 * user/owner of this mm. All of the following must be true in
418 * order for it to be changed:
420 * current == mm->owner
422 * new_owner->mm == mm
423 * new_owner->alloc_lock is held
425 struct task_struct __rcu *owner;
428 /* store ref to file /proc/<pid>/exe symlink points to */
429 struct file *exe_file;
430 #ifdef CONFIG_MMU_NOTIFIER
431 struct mmu_notifier_mm *mmu_notifier_mm;
433 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
434 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
436 #ifdef CONFIG_CPUMASK_OFFSTACK
437 struct cpumask cpumask_allocation;
439 #ifdef CONFIG_NUMA_BALANCING
441 * numa_next_scan is the next time that the PTEs will be marked
442 * pte_numa. NUMA hinting faults will gather statistics and migrate
443 * pages to new nodes if necessary.
445 unsigned long numa_next_scan;
447 /* Restart point for scanning and setting pte_numa */
448 unsigned long numa_scan_offset;
450 /* numa_scan_seq prevents two threads setting pte_numa */
453 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
455 * An operation with batched TLB flushing is going on. Anything that
456 * can move process memory needs to flush the TLB when moving a
457 * PROT_NONE or PROT_NUMA mapped page.
459 bool tlb_flush_pending;
461 struct uprobes_state uprobes_state;
462 #ifdef CONFIG_X86_INTEL_MPX
463 /* address of the bounds directory */
464 void __user *bd_addr;
468 static inline void mm_init_cpumask(struct mm_struct *mm)
470 #ifdef CONFIG_CPUMASK_OFFSTACK
471 mm->cpu_vm_mask_var = &mm->cpumask_allocation;
473 cpumask_clear(mm->cpu_vm_mask_var);
476 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
477 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
479 return mm->cpu_vm_mask_var;
482 #if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
484 * Memory barriers to keep this state in sync are graciously provided by
485 * the page table locks, outside of which no page table modifications happen.
486 * The barriers below prevent the compiler from re-ordering the instructions
487 * around the memory barriers that are already present in the code.
489 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
492 return mm->tlb_flush_pending;
494 static inline void set_tlb_flush_pending(struct mm_struct *mm)
496 mm->tlb_flush_pending = true;
499 * Guarantee that the tlb_flush_pending store does not leak into the
500 * critical section updating the page tables
502 smp_mb__before_spinlock();
504 /* Clearing is done after a TLB flush, which also provides a barrier. */
505 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
508 mm->tlb_flush_pending = false;
511 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
515 static inline void set_tlb_flush_pending(struct mm_struct *mm)
518 static inline void clear_tlb_flush_pending(struct mm_struct *mm)
523 struct vm_special_mapping
529 enum tlb_flush_reason {
530 TLB_FLUSH_ON_TASK_SWITCH,
531 TLB_REMOTE_SHOOTDOWN,
533 TLB_LOCAL_MM_SHOOTDOWN,
534 NR_TLB_FLUSH_REASONS,
537 #endif /* _LINUX_MM_TYPES_H */