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/prio_tree.h>
10 #include <linux/rbtree.h>
11 #include <linux/rwsem.h>
12 #include <linux/completion.h>
13 #include <linux/cpumask.h>
14 #include <linux/page-debug-flags.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 first free object */
59 /* Used for cmpxchg_double in slub */
60 unsigned long counters;
65 atomic_t _mapcount; /* Count of ptes mapped in mms,
66 * to show when page is mapped
67 * & limit reverse map searches.
76 atomic_t _count; /* Usage count, see below. */
81 /* Third double word block */
82 struct list_head lru; /* Pageout list, eg. active_list
83 * protected by zone->lru_lock !
86 /* Remainder is not double word aligned */
88 unsigned long private; /* Mapping-private opaque data:
89 * usually used for buffer_heads
90 * if PagePrivate set; used for
91 * swp_entry_t if PageSwapCache;
92 * indicates order in the buddy
93 * system if PG_buddy is set.
98 struct kmem_cache *slab; /* SLUB: Pointer to slab */
99 struct page *first_page; /* Compound tail pages */
103 * On machines where all RAM is mapped into kernel address space,
104 * we can simply calculate the virtual address. On machines with
105 * highmem some memory is mapped into kernel virtual memory
106 * dynamically, so we need a place to store that address.
107 * Note that this field could be 16 bits on x86 ... ;)
109 * Architectures with slow multiplication can define
110 * WANT_PAGE_VIRTUAL in asm/page.h
112 #if defined(WANT_PAGE_VIRTUAL)
113 void *virtual; /* Kernel virtual address (NULL if
114 not kmapped, ie. highmem) */
115 #endif /* WANT_PAGE_VIRTUAL */
116 #ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
117 unsigned long debug_flags; /* Use atomic bitops on this */
120 #ifdef CONFIG_KMEMCHECK
122 * kmemcheck wants to track the status of each byte in a page; this
123 * is a pointer to such a status block. NULL if not tracked.
129 * If another subsystem starts using the double word pairing for atomic
130 * operations on struct page then it must change the #if to ensure
131 * proper alignment of the page struct.
133 #if defined(CONFIG_SLUB) && defined(CONFIG_CMPXCHG_LOCAL)
134 __attribute__((__aligned__(2*sizeof(unsigned long))))
140 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
149 typedef unsigned long __nocast vm_flags_t;
152 * A region containing a mapping of a non-memory backed file under NOMMU
153 * conditions. These are held in a global tree and are pinned by the VMAs that
157 struct rb_node vm_rb; /* link in global region tree */
158 vm_flags_t vm_flags; /* VMA vm_flags */
159 unsigned long vm_start; /* start address of region */
160 unsigned long vm_end; /* region initialised to here */
161 unsigned long vm_top; /* region allocated to here */
162 unsigned long vm_pgoff; /* the offset in vm_file corresponding to vm_start */
163 struct file *vm_file; /* the backing file or NULL */
165 int vm_usage; /* region usage count (access under nommu_region_sem) */
166 bool vm_icache_flushed : 1; /* true if the icache has been flushed for
171 * This struct defines a memory VMM memory area. There is one of these
172 * per VM-area/task. A VM area is any part of the process virtual memory
173 * space that has a special rule for the page-fault handlers (ie a shared
174 * library, the executable area etc).
176 struct vm_area_struct {
177 struct mm_struct * vm_mm; /* The address space we belong to. */
178 unsigned long vm_start; /* Our start address within vm_mm. */
179 unsigned long vm_end; /* The first byte after our end address
182 /* linked list of VM areas per task, sorted by address */
183 struct vm_area_struct *vm_next, *vm_prev;
185 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
186 unsigned long vm_flags; /* Flags, see mm.h. */
188 struct rb_node vm_rb;
191 * For areas with an address space and backing store,
192 * linkage into the address_space->i_mmap prio tree, or
193 * linkage to the list of like vmas hanging off its node, or
194 * linkage of vma in the address_space->i_mmap_nonlinear list.
198 struct list_head list;
199 void *parent; /* aligns with prio_tree_node parent */
200 struct vm_area_struct *head;
203 struct raw_prio_tree_node prio_tree_node;
207 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
208 * list, after a COW of one of the file pages. A MAP_SHARED vma
209 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
210 * or brk vma (with NULL file) can only be in an anon_vma list.
212 struct list_head anon_vma_chain; /* Serialized by mmap_sem &
214 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
216 /* Function pointers to deal with this struct. */
217 const struct vm_operations_struct *vm_ops;
219 /* Information about our backing store: */
220 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
221 units, *not* PAGE_CACHE_SIZE */
222 struct file * vm_file; /* File we map to (can be NULL). */
223 void * vm_private_data; /* was vm_pte (shared mem) */
226 struct vm_region *vm_region; /* NOMMU mapping region */
229 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
234 struct task_struct *task;
235 struct core_thread *next;
240 struct core_thread dumper;
241 struct completion startup;
251 #if USE_SPLIT_PTLOCKS && defined(CONFIG_MMU)
252 #define SPLIT_RSS_COUNTING
253 /* per-thread cached information, */
254 struct task_rss_stat {
255 int events; /* for synchronization threshold */
256 int count[NR_MM_COUNTERS];
258 #endif /* USE_SPLIT_PTLOCKS */
261 atomic_long_t count[NR_MM_COUNTERS];
265 struct vm_area_struct * mmap; /* list of VMAs */
266 struct rb_root mm_rb;
267 struct vm_area_struct * mmap_cache; /* last find_vma result */
269 unsigned long (*get_unmapped_area) (struct file *filp,
270 unsigned long addr, unsigned long len,
271 unsigned long pgoff, unsigned long flags);
272 void (*unmap_area) (struct mm_struct *mm, unsigned long addr);
274 unsigned long mmap_base; /* base of mmap area */
275 unsigned long task_size; /* size of task vm space */
276 unsigned long cached_hole_size; /* if non-zero, the largest hole below free_area_cache */
277 unsigned long free_area_cache; /* first hole of size cached_hole_size or larger */
279 atomic_t mm_users; /* How many users with user space? */
280 atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
281 int map_count; /* number of VMAs */
283 spinlock_t page_table_lock; /* Protects page tables and some counters */
284 struct rw_semaphore mmap_sem;
286 struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
287 * together off init_mm.mmlist, and are protected
292 unsigned long hiwater_rss; /* High-watermark of RSS usage */
293 unsigned long hiwater_vm; /* High-water virtual memory usage */
295 unsigned long total_vm, locked_vm, shared_vm, exec_vm;
296 unsigned long stack_vm, reserved_vm, def_flags, nr_ptes;
297 unsigned long start_code, end_code, start_data, end_data;
298 unsigned long start_brk, brk, start_stack;
299 unsigned long arg_start, arg_end, env_start, env_end;
301 unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */
304 * Special counters, in some configurations protected by the
305 * page_table_lock, in other configurations by being atomic.
307 struct mm_rss_stat rss_stat;
309 struct linux_binfmt *binfmt;
311 cpumask_var_t cpu_vm_mask_var;
313 /* Architecture-specific MM context */
314 mm_context_t context;
316 /* Swap token stuff */
318 * Last value of global fault stamp as seen by this process.
319 * In other words, this value gives an indication of how long
320 * it has been since this task got the token.
321 * Look at mm/thrash.c
323 unsigned int faultstamp;
324 unsigned int token_priority;
325 unsigned int last_interval;
327 /* How many tasks sharing this mm are OOM_DISABLE */
328 atomic_t oom_disable_count;
330 unsigned long flags; /* Must use atomic bitops to access the bits */
332 struct core_state *core_state; /* coredumping support */
334 spinlock_t ioctx_lock;
335 struct hlist_head ioctx_list;
337 #ifdef CONFIG_MM_OWNER
339 * "owner" points to a task that is regarded as the canonical
340 * user/owner of this mm. All of the following must be true in
341 * order for it to be changed:
343 * current == mm->owner
345 * new_owner->mm == mm
346 * new_owner->alloc_lock is held
348 struct task_struct __rcu *owner;
351 /* store ref to file /proc/<pid>/exe symlink points to */
352 struct file *exe_file;
353 unsigned long num_exe_file_vmas;
354 #ifdef CONFIG_MMU_NOTIFIER
355 struct mmu_notifier_mm *mmu_notifier_mm;
357 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
358 pgtable_t pmd_huge_pte; /* protected by page_table_lock */
360 #ifdef CONFIG_CPUMASK_OFFSTACK
361 struct cpumask cpumask_allocation;
365 static inline void mm_init_cpumask(struct mm_struct *mm)
367 #ifdef CONFIG_CPUMASK_OFFSTACK
368 mm->cpu_vm_mask_var = &mm->cpumask_allocation;
372 /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
373 static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
375 return mm->cpu_vm_mask_var;
378 #endif /* _LINUX_MM_TYPES_H */