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>
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))
25 #define USE_SPLIT_PTLOCKS (NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
28 * Each physical page in the system has a struct page associated with
29 * it to keep track of whatever it is we are using the page for at the
30 * moment. Note that we have no way to track which tasks are using
31 * a page, though if it is a pagecache page, rmap structures can tell us
34 * The objects in struct page are organized in double word blocks in
35 * order to allows us to use atomic double word operations on portions
36 * of struct page. That is currently only used by slub but the arrangement
37 * allows the use of atomic double word operations on the flags/mapping
38 * and lru list pointers also.
41 /* First double word block */
42 unsigned long flags; /* Atomic flags, some possibly
43 * updated asynchronously */
44 struct address_space *mapping; /* If low bit clear, points to
45 * inode address_space, or NULL.
46 * If page mapped as anonymous
47 * memory, low bit is set, and
48 * it points to anon_vma object:
49 * see PAGE_MAPPING_ANON below.
51 /* Second double word */
54 pgoff_t index; /* Our offset within mapping. */
55 void *freelist; /* slub/slob first free object */
56 bool pfmemalloc; /* If set by the page allocator,
57 * ALLOC_NO_WATERMARKS was set
58 * and the low watermark was not
59 * met implying that the system
60 * is under some pressure. The
61 * caller should try ensure
62 * this page is only used to
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. */
114 /* Third double word block */
116 struct list_head lru; /* Pageout list, eg. active_list
117 * protected by zone->lru_lock !
119 struct { /* slub per cpu partial pages */
120 struct page *next; /* Next partial slab */
122 int pages; /* Nr of partial slabs left */
123 int pobjects; /* Approximate # of objects */
130 struct list_head list; /* slobs list of pages */
131 struct { /* slab fields */
132 struct kmem_cache *slab_cache;
133 struct slab *slab_page;
137 /* Remainder is not double word aligned */
139 unsigned long private; /* Mapping-private opaque data:
140 * usually used for buffer_heads
141 * if PagePrivate set; used for
142 * swp_entry_t if PageSwapCache;
143 * indicates order in the buddy
144 * system if PG_buddy is set.
146 #if USE_SPLIT_PTLOCKS
149 struct kmem_cache *slab; /* SLUB: Pointer to slab */
150 struct page *first_page; /* Compound tail pages */
154 * On machines where all RAM is mapped into kernel address space,
155 * we can simply calculate the virtual address. On machines with
156 * highmem some memory is mapped into kernel virtual memory
157 * dynamically, so we need a place to store that address.
158 * Note that this field could be 16 bits on x86 ... ;)
160 * Architectures with slow multiplication can define
161 * WANT_PAGE_VIRTUAL in asm/page.h
163 #if defined(WANT_PAGE_VIRTUAL)
164 void *virtual; /* Kernel virtual address (NULL if
165 not kmapped, ie. highmem) */
166 #endif /* WANT_PAGE_VIRTUAL */
167 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
168 unsigned long debug_flags; /* Use atomic bitops on this */
171 #ifdef CONFIG_KMEMCHECK
173 * kmemcheck wants to track the status of each byte in a page; this
174 * is a pointer to such a status block. NULL if not tracked.
180 * The struct page can be forced to be double word aligned so that atomic ops
181 * on double words work. The SLUB allocator can make use of such a feature.
183 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
184 __aligned(2 * sizeof(unsigned long))
190 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
199 typedef unsigned long __nocast vm_flags_t;
202 * A region containing a mapping of a non-memory backed file under NOMMU
203 * conditions. These are held in a global tree and are pinned by the VMAs that
207 struct rb_node vm_rb; /* link in global region tree */
208 vm_flags_t vm_flags; /* VMA vm_flags */
209 unsigned long vm_start; /* start address of region */
210 unsigned long vm_end; /* region initialised to here */
211 unsigned long vm_top; /* region allocated to here */
212 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
213 struct file *vm_file; /* the backing file or NULL */
215 int vm_usage; /* region usage count (access under nommu_region_sem) */
216 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
221 * This struct defines a memory VMM memory area. There is one of these
222 * per VM-area/task. A VM area is any part of the process virtual memory
223 * space that has a special rule for the page-fault handlers (ie a shared
224 * library, the executable area etc).
226 struct vm_area_struct {
227 /* The first cache line has the info for VMA tree walking. */
229 unsigned long vm_start; /* Our start address within vm_mm. */
230 unsigned long vm_end; /* The first byte after our end address
233 /* linked list of VM areas per task, sorted by address */
234 struct vm_area_struct *vm_next, *vm_prev;
236 struct rb_node vm_rb;
239 * Largest free memory gap in bytes to the left of this VMA.
240 * Either between this VMA and vma->vm_prev, or between one of the
241 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
242 * get_unmapped_area find a free area of the right size.
244 unsigned long rb_subtree_gap;
246 /* Second cache line starts here. */
248 struct mm_struct *vm_mm; /* The address space we belong to. */
249 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
250 unsigned long vm_flags; /* Flags, see mm.h. */
253 * For areas with an address space and backing store,
254 * linkage into the address_space->i_mmap interval tree, or
255 * linkage of vma in the address_space->i_mmap_nonlinear list.
260 unsigned long rb_subtree_last;
262 struct list_head nonlinear;
266 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
267 * list, after a COW of one of the file pages. A MAP_SHARED vma
268 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
269 * or brk vma (with NULL file) can only be in an anon_vma list.
271 struct list_head anon_vma_chain; /* Serialized by mmap_sem &
273 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
275 /* Function pointers to deal with this struct. */
276 const struct vm_operations_struct *vm_ops;
278 /* Information about our backing store: */
279 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
280 units, *not* PAGE_CACHE_SIZE */
281 struct file * vm_file; /* File we map to (can be NULL). */
282 void * vm_private_data; /* was vm_pte (shared mem) */
285 struct vm_region *vm_region; /* NOMMU mapping region */
288 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
293 struct task_struct *task;
294 struct core_thread *next;
299 struct core_thread dumper;
300 struct completion startup;
310 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
311 #define SPLIT_RSS_COUNTING
312 /* per-thread cached information, */
313 struct task_rss_stat {
314 int events; /* for synchronization threshold */
315 int count[NR_MM_COUNTERS];
317 #endif /* USE_SPLIT_PTLOCKS */
320 atomic_long_t count[NR_MM_COUNTERS];
324 struct vm_area_struct * mmap; /* list of VMAs */
325 struct rb_root mm_rb;
326 struct vm_area_struct * mmap_cache; /* last find_vma result */
328 unsigned long (*get_unmapped_area) (struct file *filp,
329 unsigned long addr, unsigned long len,
330 unsigned long pgoff, unsigned long flags);
331 void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
333 unsigned long mmap_base; /* base of mmap area */
334 unsigned long task_size; /* size of task vm space */
335 unsigned long cached_hole_size; /* if non-zero, the largest hole below free_area_cache */
336 unsigned long free_area_cache; /* first hole of size cached_hole_size or larger */
337 unsigned long highest_vm_end; /* highest vma end address */
339 atomic_t mm_users; /* How many users with user space? */
340 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
341 int map_count; /* number of VMAs */
343 spinlock_t page_table_lock; /* Protects page tables and some counters */
344 struct rw_semaphore mmap_sem;
346 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
347 * together off init_mm.mmlist, and are protected
352 unsigned long hiwater_rss; /* High-watermark of RSS usage */
353 unsigned long hiwater_vm; /* High-water virtual memory usage */
355 unsigned long total_vm; /* Total pages mapped */
356 unsigned long locked_vm; /* Pages that have PG_mlocked set */
357 unsigned long pinned_vm; /* Refcount permanently increased */
358 unsigned long shared_vm; /* Shared pages (files) */
359 unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */
360 unsigned long stack_vm; /* VM_GROWSUP/DOWN */
361 unsigned long def_flags;
362 unsigned long nr_ptes; /* Page table pages */
363 unsigned long start_code, end_code, start_data, end_data;
364 unsigned long start_brk, brk, start_stack;
365 unsigned long arg_start, arg_end, env_start, env_end;
367 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
370 * Special counters, in some configurations protected by the
371 * page_table_lock, in other configurations by being atomic.
373 struct mm_rss_stat rss_stat;
375 struct linux_binfmt *binfmt;
377 cpumask_var_t cpu_vm_mask_var;
379 /* Architecture-specific MM context */
380 mm_context_t context;
382 unsigned long flags; /* Must use atomic bitops to access the bits */
384 struct core_state *core_state; /* coredumping support */
386 spinlock_t ioctx_lock;
387 struct hlist_head ioctx_list;
389 #ifdef CONFIG_MM_OWNER
391 * "owner" points to a task that is regarded as the canonical
392 * user/owner of this mm. All of the following must be true in
393 * order for it to be changed:
395 * current == mm->owner
397 * new_owner->mm == mm
398 * new_owner->alloc_lock is held
400 struct task_struct __rcu *owner;
403 /* store ref to file /proc/<pid>/exe symlink points to */
404 struct file *exe_file;
405 #ifdef CONFIG_MMU_NOTIFIER
406 struct mmu_notifier_mm *mmu_notifier_mm;
408 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
409 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
411 #ifdef CONFIG_CPUMASK_OFFSTACK
412 struct cpumask cpumask_allocation;
414 struct uprobes_state uprobes_state;
417 static inline void mm_init_cpumask(struct mm_struct *mm)
419 #ifdef CONFIG_CPUMASK_OFFSTACK
420 mm->cpu_vm_mask_var = &mm->cpumask_allocation;
424 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
425 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
427 return mm->cpu_vm_mask_var;
430 #endif /* _LINUX_MM_TYPES_H */