File: mm_types.h

package info (click to toggle)
linux 3.16.56-1+deb8u1
  • links: PTS, VCS
  • area: main
  • in suites: jessie
  • size: 739,780 kB
  • sloc: ansic: 12,238,760; asm: 277,795; perl: 53,071; xml: 47,771; makefile: 30,548; sh: 7,977; python: 6,699; cpp: 5,132; yacc: 4,254; lex: 2,215; awk: 741; pascal: 231; lisp: 218; sed: 30
file content (535 lines) | stat: -rw-r--r-- 15,617 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
#ifndef _LINUX_MM_TYPES_H
#define _LINUX_MM_TYPES_H

#include <linux/auxvec.h>
#include <linux/types.h>
#include <linux/threads.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
#include <linux/page-debug-flags.h>
#include <linux/uprobes.h>
#include <linux/page-flags-layout.h>
#include <asm/page.h>
#include <asm/mmu.h>

#ifndef AT_VECTOR_SIZE_ARCH
#define AT_VECTOR_SIZE_ARCH 0
#endif
#define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))

struct address_space;

#define USE_SPLIT_PTE_PTLOCKS	(NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
#define USE_SPLIT_PMD_PTLOCKS	(USE_SPLIT_PTE_PTLOCKS && \
		IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
#define ALLOC_SPLIT_PTLOCKS	(SPINLOCK_SIZE > BITS_PER_LONG/8)

/*
 * Each physical page in the system has a struct page associated with
 * it to keep track of whatever it is we are using the page for at the
 * moment. Note that we have no way to track which tasks are using
 * a page, though if it is a pagecache page, rmap structures can tell us
 * who is mapping it.
 *
 * The objects in struct page are organized in double word blocks in
 * order to allows us to use atomic double word operations on portions
 * of struct page. That is currently only used by slub but the arrangement
 * allows the use of atomic double word operations on the flags/mapping
 * and lru list pointers also.
 */
struct page {
	/* First double word block */
	unsigned long flags;		/* Atomic flags, some possibly
					 * updated asynchronously */
	union {
		struct address_space *mapping;	/* If low bit clear, points to
						 * inode address_space, or NULL.
						 * If page mapped as anonymous
						 * memory, low bit is set, and
						 * it points to anon_vma object:
						 * see PAGE_MAPPING_ANON below.
						 */
		void *s_mem;			/* slab first object */
	};

	/* Second double word */
	struct {
		union {
			pgoff_t index;		/* Our offset within mapping. */
			void *freelist;		/* sl[aou]b first free object */
			bool pfmemalloc;	/* If set by the page allocator,
						 * ALLOC_NO_WATERMARKS was set
						 * and the low watermark was not
						 * met implying that the system
						 * is under some pressure. The
						 * caller should try ensure
						 * this page is only used to
						 * free other pages.
						 */
		};

		union {
#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
	defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
			/* Used for cmpxchg_double in slub */
			unsigned long counters;
#else
			/*
			 * Keep _count separate from slub cmpxchg_double data.
			 * As the rest of the double word is protected by
			 * slab_lock but _count is not.
			 */
			unsigned counters;
#endif

			struct {

				union {
					/*
					 * Count of ptes mapped in
					 * mms, to show when page is
					 * mapped & limit reverse map
					 * searches.
					 *
					 * Used also for tail pages
					 * refcounting instead of
					 * _count. Tail pages cannot
					 * be mapped and keeping the
					 * tail page _count zero at
					 * all times guarantees
					 * get_page_unless_zero() will
					 * never succeed on tail
					 * pages.
					 */
					atomic_t _mapcount;

					struct { /* SLUB */
						unsigned inuse:16;
						unsigned objects:15;
						unsigned frozen:1;
					};
					int units;	/* SLOB */
				};
				atomic_t _count;		/* Usage count, see below. */
			};
			unsigned int active;	/* SLAB */
		};
	};

	/* Third double word block */
	union {
		struct list_head lru;	/* Pageout list, eg. active_list
					 * protected by zone->lru_lock !
					 * Can be used as a generic list
					 * by the page owner.
					 */
		struct {		/* slub per cpu partial pages */
			struct page *next;	/* Next partial slab */
#ifdef CONFIG_64BIT
			int pages;	/* Nr of partial slabs left */
			int pobjects;	/* Approximate # of objects */
#else
			short int pages;
			short int pobjects;
#endif
		};

		struct slab *slab_page; /* slab fields */
		struct rcu_head rcu_head;	/* Used by SLAB
						 * when destroying via RCU
						 */
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
		pgtable_t pmd_huge_pte; /* protected by page->ptl */
#endif
	};

	/* Remainder is not double word aligned */
	union {
		unsigned long private;		/* Mapping-private opaque data:
					 	 * usually used for buffer_heads
						 * if PagePrivate set; used for
						 * swp_entry_t if PageSwapCache;
						 * indicates order in the buddy
						 * system if PG_buddy is set.
						 */
#if USE_SPLIT_PTE_PTLOCKS
#if ALLOC_SPLIT_PTLOCKS
		spinlock_t *ptl;
#else
		spinlock_t ptl;
#endif
#endif
		struct kmem_cache *slab_cache;	/* SL[AU]B: Pointer to slab */
		struct page *first_page;	/* Compound tail pages */
	};

	/*
	 * On machines where all RAM is mapped into kernel address space,
	 * we can simply calculate the virtual address. On machines with
	 * highmem some memory is mapped into kernel virtual memory
	 * dynamically, so we need a place to store that address.
	 * Note that this field could be 16 bits on x86 ... ;)
	 *
	 * Architectures with slow multiplication can define
	 * WANT_PAGE_VIRTUAL in asm/page.h
	 */
#if defined(WANT_PAGE_VIRTUAL)
	void *virtual;			/* Kernel virtual address (NULL if
					   not kmapped, ie. highmem) */
#endif /* WANT_PAGE_VIRTUAL */
#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS
	unsigned long debug_flags;	/* Use atomic bitops on this */
#endif

#ifdef CONFIG_KMEMCHECK
	/*
	 * kmemcheck wants to track the status of each byte in a page; this
	 * is a pointer to such a status block. NULL if not tracked.
	 */
	void *shadow;
#endif

#ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
	int _last_cpupid;
#endif
}
/*
 * The struct page can be forced to be double word aligned so that atomic ops
 * on double words work. The SLUB allocator can make use of such a feature.
 */
#ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
	__aligned(2 * sizeof(unsigned long))
#endif
;

struct page_frag {
	struct page *page;
#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
	__u32 offset;
	__u32 size;
#else
	__u16 offset;
	__u16 size;
#endif
};

typedef unsigned long __nocast vm_flags_t;

/*
 * A region containing a mapping of a non-memory backed file under NOMMU
 * conditions.  These are held in a global tree and are pinned by the VMAs that
 * map parts of them.
 */
struct vm_region {
	struct rb_node	vm_rb;		/* link in global region tree */
	vm_flags_t	vm_flags;	/* VMA vm_flags */
	unsigned long	vm_start;	/* start address of region */
	unsigned long	vm_end;		/* region initialised to here */
	unsigned long	vm_top;		/* region allocated to here */
	unsigned long	vm_pgoff;	/* the offset in vm_file corresponding to vm_start */
	struct file	*vm_file;	/* the backing file or NULL */
	struct file	*vm_prfile;	/* the virtual backing file or NULL */

	int		vm_usage;	/* region usage count (access under nommu_region_sem) */
	bool		vm_icache_flushed : 1; /* true if the icache has been flushed for
						* this region */
};

/*
 * This struct defines a memory VMM memory area. There is one of these
 * per VM-area/task.  A VM area is any part of the process virtual memory
 * space that has a special rule for the page-fault handlers (ie a shared
 * library, the executable area etc).
 */
struct vm_area_struct {
	/* The first cache line has the info for VMA tree walking. */

	unsigned long vm_start;		/* Our start address within vm_mm. */
	unsigned long vm_end;		/* The first byte after our end address
					   within vm_mm. */

	/* linked list of VM areas per task, sorted by address */
	struct vm_area_struct *vm_next, *vm_prev;

	struct rb_node vm_rb;

	/*
	 * Largest free memory gap in bytes to the left of this VMA.
	 * Either between this VMA and vma->vm_prev, or between one of the
	 * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
	 * get_unmapped_area find a free area of the right size.
	 */
	unsigned long rb_subtree_gap;

	/* Second cache line starts here. */

	struct mm_struct *vm_mm;	/* The address space we belong to. */
	pgprot_t vm_page_prot;		/* Access permissions of this VMA. */
	unsigned long vm_flags;		/* Flags, see mm.h. */

	/*
	 * For areas with an address space and backing store,
	 * linkage into the address_space->i_mmap interval tree, or
	 * linkage of vma in the address_space->i_mmap_nonlinear list.
	 */
	union {
		struct {
			struct rb_node rb;
			unsigned long rb_subtree_last;
		} linear;
		struct list_head nonlinear;
	} shared;

	/*
	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
	 * list, after a COW of one of the file pages.	A MAP_SHARED vma
	 * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
	 * or brk vma (with NULL file) can only be in an anon_vma list.
	 */
	struct list_head anon_vma_chain; /* Serialized by mmap_sem &
					  * page_table_lock */
	struct anon_vma *anon_vma;	/* Serialized by page_table_lock */

	/* Function pointers to deal with this struct. */
	const struct vm_operations_struct *vm_ops;

	/* Information about our backing store: */
	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
					   units, *not* PAGE_CACHE_SIZE */
	struct file * vm_file;		/* File we map to (can be NULL). */
	struct file *vm_prfile;		/* shadow of vm_file */
	void * vm_private_data;		/* was vm_pte (shared mem) */

#ifndef CONFIG_MMU
	struct vm_region *vm_region;	/* NOMMU mapping region */
#endif
#ifdef CONFIG_NUMA
	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */
#endif
};

struct core_thread {
	struct task_struct *task;
	struct core_thread *next;
};

struct core_state {
	atomic_t nr_threads;
	struct core_thread dumper;
	struct completion startup;
};

enum {
	MM_FILEPAGES,
	MM_ANONPAGES,
	MM_SWAPENTS,
	NR_MM_COUNTERS
};

#if USE_SPLIT_PTE_PTLOCKS && defined(CONFIG_MMU)
#define SPLIT_RSS_COUNTING
/* per-thread cached information, */
struct task_rss_stat {
	int events;	/* for synchronization threshold */
	int count[NR_MM_COUNTERS];
};
#endif /* USE_SPLIT_PTE_PTLOCKS */

struct mm_rss_stat {
	atomic_long_t count[NR_MM_COUNTERS];
};

struct kioctx_table;
struct mm_struct {
	struct vm_area_struct *mmap;		/* list of VMAs */
	struct rb_root mm_rb;
	u32 vmacache_seqnum;                   /* per-thread vmacache */
#ifdef CONFIG_MMU
	unsigned long (*get_unmapped_area) (struct file *filp,
				unsigned long addr, unsigned long len,
				unsigned long pgoff, unsigned long flags);
#endif
	unsigned long mmap_base;		/* base of mmap area */
	unsigned long mmap_legacy_base;         /* base of mmap area in bottom-up allocations */
	unsigned long task_size;		/* size of task vm space */
	unsigned long highest_vm_end;		/* highest vma end address */
	pgd_t * pgd;
	atomic_t mm_users;			/* How many users with user space? */
	atomic_t mm_count;			/* How many references to "struct mm_struct" (users count as 1) */
	atomic_long_t nr_ptes;			/* Page table pages */
	int map_count;				/* number of VMAs */

	spinlock_t page_table_lock;		/* Protects page tables and some counters */
	struct rw_semaphore mmap_sem;

	struct list_head mmlist;		/* List of maybe swapped mm's.	These are globally strung
						 * together off init_mm.mmlist, and are protected
						 * by mmlist_lock
						 */


	unsigned long hiwater_rss;	/* High-watermark of RSS usage */
	unsigned long hiwater_vm;	/* High-water virtual memory usage */

	unsigned long total_vm;		/* Total pages mapped */
	unsigned long locked_vm;	/* Pages that have PG_mlocked set */
	unsigned long pinned_vm;	/* Refcount permanently increased */
	unsigned long shared_vm;	/* Shared pages (files) */
	unsigned long exec_vm;		/* VM_EXEC & ~VM_WRITE */
	unsigned long stack_vm;		/* VM_GROWSUP/DOWN */
	unsigned long def_flags;
	unsigned long start_code, end_code, start_data, end_data;
	unsigned long start_brk, brk, start_stack;
	unsigned long arg_start, arg_end, env_start, env_end;

	unsigned long saved_auxv[AT_VECTOR_SIZE]; /* for /proc/PID/auxv */

	/*
	 * Special counters, in some configurations protected by the
	 * page_table_lock, in other configurations by being atomic.
	 */
	struct mm_rss_stat rss_stat;

	struct linux_binfmt *binfmt;

	cpumask_var_t cpu_vm_mask_var;

	/* Architecture-specific MM context */
	mm_context_t context;

	unsigned long flags; /* Must use atomic bitops to access the bits */

	struct core_state *core_state; /* coredumping support */
#ifdef CONFIG_AIO
	spinlock_t			ioctx_lock;
	struct kioctx_table __rcu	*ioctx_table;
#endif
#ifdef CONFIG_MEMCG
	/*
	 * "owner" points to a task that is regarded as the canonical
	 * user/owner of this mm. All of the following must be true in
	 * order for it to be changed:
	 *
	 * current == mm->owner
	 * current->mm != mm
	 * new_owner->mm == mm
	 * new_owner->alloc_lock is held
	 */
	struct task_struct __rcu *owner;
#endif
	struct user_namespace *user_ns;

	/* store ref to file /proc/<pid>/exe symlink points to */
	struct file *exe_file;
#ifdef CONFIG_MMU_NOTIFIER
	struct mmu_notifier_mm *mmu_notifier_mm;
#endif
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
	pgtable_t pmd_huge_pte; /* protected by page_table_lock */
#endif
#ifdef CONFIG_CPUMASK_OFFSTACK
	struct cpumask cpumask_allocation;
#endif
#ifdef CONFIG_NUMA_BALANCING
	/*
	 * numa_next_scan is the next time that the PTEs will be marked
	 * pte_numa. NUMA hinting faults will gather statistics and migrate
	 * pages to new nodes if necessary.
	 */
	unsigned long numa_next_scan;

	/* Restart point for scanning and setting pte_numa */
	unsigned long numa_scan_offset;

	/* numa_scan_seq prevents two threads setting pte_numa */
	int numa_scan_seq;
#endif
#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
	/*
	 * An operation with batched TLB flushing is going on. Anything that
	 * can move process memory needs to flush the TLB when moving a
	 * PROT_NONE or PROT_NUMA mapped page.
	 */
	atomic_t tlb_flush_pending;
#endif
	struct uprobes_state uprobes_state;
};

static inline void mm_init_cpumask(struct mm_struct *mm)
{
#ifdef CONFIG_CPUMASK_OFFSTACK
	mm->cpu_vm_mask_var = &mm->cpumask_allocation;
#endif
}

/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */
static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
{
	return mm->cpu_vm_mask_var;
}

#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
/*
 * Memory barriers to keep this state in sync are graciously provided by
 * the page table locks, outside of which no page table modifications happen.
 * The barriers below prevent the compiler from re-ordering the instructions
 * around the memory barriers that are already present in the code.
 */
static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
{
	barrier();
	return atomic_read(&mm->tlb_flush_pending) > 0;
}

static inline void init_tlb_flush_pending(struct mm_struct *mm)
{
	atomic_set(&mm->tlb_flush_pending, 0);
}

static inline void inc_tlb_flush_pending(struct mm_struct *mm)
{
	atomic_inc(&mm->tlb_flush_pending);

	/*
	 * Guarantee that the tlb_flush_pending increase does not leak into the
	 * critical section updating the page tables
	 */
	smp_mb__before_spinlock();
}

/* Clearing is done after a TLB flush, which also provides a barrier. */
static inline void dec_tlb_flush_pending(struct mm_struct *mm)
{
	barrier();
	atomic_dec(&mm->tlb_flush_pending);
}
#else
static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
{
	return false;
}

static inline void init_tlb_flush_pending(struct mm_struct *mm)
{
}

static inline void inc_tlb_flush_pending(struct mm_struct *mm)
{
}

static inline void dec_tlb_flush_pending(struct mm_struct *mm)
{
}
#endif

struct vm_special_mapping
{
	const char *name;
	struct page **pages;
};

#endif /* _LINUX_MM_TYPES_H */