summaryrefslogtreecommitdiff
path: root/pfinet/linux-src/include/linux/mm.h
blob: 232c53dcb32959afa52cc007aa952135f7d6f891 (plain)
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
#ifndef _LINUX_MM_H
#define _LINUX_MM_H

#include <linux/sched.h>
#include <linux/errno.h>

#ifdef __KERNEL__

#include <linux/string.h>

extern unsigned long max_mapnr;
extern unsigned long num_physpages;
extern void * high_memory;
extern int page_cluster;

#include <asm/page.h>
#include <asm/atomic.h>

/*
 * Linux kernel virtual memory manager primitives.
 * The idea being to have a "virtual" mm in the same way
 * we have a virtual fs - giving a cleaner interface to the
 * mm details, and allowing different kinds of memory mappings
 * (from shared memory to executable loading to arbitrary
 * mmap() functions).
 */

/*
 * 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 {
	struct mm_struct * vm_mm;	/* VM area parameters */
	unsigned long vm_start;
	unsigned long vm_end;

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

	pgprot_t vm_page_prot;
	unsigned short vm_flags;

	/* AVL tree of VM areas per task, sorted by address */
	short vm_avl_height;
	struct vm_area_struct * vm_avl_left;
	struct vm_area_struct * vm_avl_right;

	/* For areas with inode, the list inode->i_mmap, for shm areas,
	 * the list of attaches, otherwise unused.
	 */
	struct vm_area_struct *vm_next_share;
	struct vm_area_struct **vm_pprev_share;

	struct vm_operations_struct * vm_ops;
	unsigned long vm_offset;
	struct file * vm_file;
	unsigned long vm_pte;			/* shared mem */
};

/*
 * vm_flags..
 */
#define VM_READ		0x0001	/* currently active flags */
#define VM_WRITE	0x0002
#define VM_EXEC		0x0004
#define VM_SHARED	0x0008

#define VM_MAYREAD	0x0010	/* limits for mprotect() etc */
#define VM_MAYWRITE	0x0020
#define VM_MAYEXEC	0x0040
#define VM_MAYSHARE	0x0080

#define VM_GROWSDOWN	0x0100	/* general info on the segment */
#define VM_GROWSUP	0x0200
#define VM_SHM		0x0400	/* shared memory area, don't swap out */
#define VM_DENYWRITE	0x0800	/* ETXTBSY on write attempts.. */

#define VM_EXECUTABLE	0x1000
#define VM_LOCKED	0x2000
#define VM_IO           0x4000  /* Memory mapped I/O or similar */

#define VM_STACK_FLAGS	0x0177

/*
 * mapping from the currently active vm_flags protection bits (the
 * low four bits) to a page protection mask..
 */
extern pgprot_t protection_map[16];


/*
 * These are the virtual MM functions - opening of an area, closing and
 * unmapping it (needed to keep files on disk up-to-date etc), pointer
 * to the functions called when a no-page or a wp-page exception occurs. 
 */
struct vm_operations_struct {
	void (*open)(struct vm_area_struct * area);
	void (*close)(struct vm_area_struct * area);
	void (*unmap)(struct vm_area_struct *area, unsigned long, size_t);
	void (*protect)(struct vm_area_struct *area, unsigned long, size_t, unsigned int newprot);
	int (*sync)(struct vm_area_struct *area, unsigned long, size_t, unsigned int flags);
	void (*advise)(struct vm_area_struct *area, unsigned long, size_t, unsigned int advise);
	unsigned long (*nopage)(struct vm_area_struct * area, unsigned long address, int write_access);
	unsigned long (*wppage)(struct vm_area_struct * area, unsigned long address,
		unsigned long page);
	int (*swapout)(struct vm_area_struct *, struct page *);
	pte_t (*swapin)(struct vm_area_struct *, unsigned long, unsigned long);
};

/*
 * Try to keep the most commonly accessed fields in single cache lines
 * here (16 bytes or greater).  This ordering should be particularly
 * beneficial on 32-bit processors.
 *
 * The first line is data used in page cache lookup, the second line
 * is used for linear searches (eg. clock algorithm scans). 
 */
typedef struct page {
	/* these must be first (free area handling) */
	struct page *next;
	struct page *prev;
	struct inode *inode;
	unsigned long offset;
	struct page *next_hash;
	atomic_t count;
	unsigned long flags;	/* atomic flags, some possibly updated asynchronously */
	struct wait_queue *wait;
	struct page **pprev_hash;
	struct buffer_head * buffers;
} mem_map_t;

/* Page flag bit values */
#define PG_locked		 0
#define PG_error		 1
#define PG_referenced		 2
#define PG_dirty		 3
#define PG_uptodate		 4
#define PG_free_after		 5
#define PG_decr_after		 6
#define PG_swap_unlock_after	 7
#define PG_DMA			 8
#define PG_Slab			 9
#define PG_swap_cache		10
#define PG_skip			11
#define PG_reserved		31

/* Make it prettier to test the above... */
#define PageLocked(page)	(test_bit(PG_locked, &(page)->flags))
#define PageError(page)		(test_bit(PG_error, &(page)->flags))
#define PageReferenced(page)	(test_bit(PG_referenced, &(page)->flags))
#define PageDirty(page)		(test_bit(PG_dirty, &(page)->flags))
#define PageUptodate(page)	(test_bit(PG_uptodate, &(page)->flags))
#define PageFreeAfter(page)	(test_bit(PG_free_after, &(page)->flags))
#define PageDecrAfter(page)	(test_bit(PG_decr_after, &(page)->flags))
#define PageSwapUnlockAfter(page) (test_bit(PG_swap_unlock_after, &(page)->flags))
#define PageDMA(page)		(test_bit(PG_DMA, &(page)->flags))
#define PageSlab(page)		(test_bit(PG_Slab, &(page)->flags))
#define PageSwapCache(page)	(test_bit(PG_swap_cache, &(page)->flags))
#define PageReserved(page)	(test_bit(PG_reserved, &(page)->flags))

#define PageSetSlab(page)	(set_bit(PG_Slab, &(page)->flags))
#define PageSetSwapCache(page)	(set_bit(PG_swap_cache, &(page)->flags))

#define PageTestandSetDirty(page)	\
			(test_and_set_bit(PG_dirty, &(page)->flags))
#define PageTestandSetSwapCache(page)	\
			(test_and_set_bit(PG_swap_cache, &(page)->flags))

#define PageClearSlab(page)	(clear_bit(PG_Slab, &(page)->flags))
#define PageClearSwapCache(page)(clear_bit(PG_swap_cache, &(page)->flags))

#define PageTestandClearDirty(page) \
			(test_and_clear_bit(PG_dirty, &(page)->flags))
#define PageTestandClearSwapCache(page)	\
			(test_and_clear_bit(PG_swap_cache, &(page)->flags))

/*
 * Various page->flags bits:
 *
 * PG_reserved is set for a page which must never be accessed (which
 * may not even be present).
 *
 * PG_DMA is set for those pages which lie in the range of
 * physical addresses capable of carrying DMA transfers.
 *
 * Multiple processes may "see" the same page. E.g. for untouched
 * mappings of /dev/null, all processes see the same page full of
 * zeroes, and text pages of executables and shared libraries have
 * only one copy in memory, at most, normally.
 *
 * For the non-reserved pages, page->count denotes a reference count.
 *   page->count == 0 means the page is free.
 *   page->count == 1 means the page is used for exactly one purpose
 *   (e.g. a private data page of one process).
 *
 * A page may be used for kmalloc() or anyone else who does a
 * get_free_page(). In this case the page->count is at least 1, and
 * all other fields are unused but should be 0 or NULL. The
 * management of this page is the responsibility of the one who uses
 * it.
 *
 * The other pages (we may call them "process pages") are completely
 * managed by the Linux memory manager: I/O, buffers, swapping etc.
 * The following discussion applies only to them.
 *
 * A page may belong to an inode's memory mapping. In this case,
 * page->inode is the pointer to the inode, and page->offset is the
 * file offset of the page (not necessarily a multiple of PAGE_SIZE).
 *
 * A page may have buffers allocated to it. In this case,
 * page->buffers is a circular list of these buffer heads. Else,
 * page->buffers == NULL.
 *
 * For pages belonging to inodes, the page->count is the number of
 * attaches, plus 1 if buffers are allocated to the page.
 *
 * All pages belonging to an inode make up a doubly linked list
 * inode->i_pages, using the fields page->next and page->prev. (These
 * fields are also used for freelist management when page->count==0.)
 * There is also a hash table mapping (inode,offset) to the page
 * in memory if present. The lists for this hash table use the fields
 * page->next_hash and page->pprev_hash.
 *
 * All process pages can do I/O:
 * - inode pages may need to be read from disk,
 * - inode pages which have been modified and are MAP_SHARED may need
 *   to be written to disk,
 * - private pages which have been modified may need to be swapped out
 *   to swap space and (later) to be read back into memory.
 * During disk I/O, PG_locked is used. This bit is set before I/O
 * and reset when I/O completes. page->wait is a wait queue of all
 * tasks waiting for the I/O on this page to complete.
 * PG_uptodate tells whether the page's contents is valid.
 * When a read completes, the page becomes uptodate, unless a disk I/O
 * error happened.
 * When a write completes, and PG_free_after is set, the page is
 * freed without any further delay.
 *
 * For choosing which pages to swap out, inode pages carry a
 * PG_referenced bit, which is set any time the system accesses
 * that page through the (inode,offset) hash table.
 *
 * PG_skip is used on sparc/sparc64 architectures to "skip" certain
 * parts of the address space.
 *
 * PG_error is set to indicate that an I/O error occurred on this page.
 */

extern mem_map_t * mem_map;

/*
 * This is timing-critical - most of the time in getting a new page
 * goes to clearing the page. If you want a page without the clearing
 * overhead, just use __get_free_page() directly..
 */
#define __get_free_page(gfp_mask) __get_free_pages((gfp_mask),0)
#define __get_dma_pages(gfp_mask, order) __get_free_pages((gfp_mask) | GFP_DMA,(order))
extern unsigned long FASTCALL(__get_free_pages(int gfp_mask, unsigned long gfp_order));

extern inline unsigned long get_free_page(int gfp_mask)
{
	unsigned long page;

	page = __get_free_page(gfp_mask);
	if (page)
		clear_page(page);
	return page;
}

extern int low_on_memory;

/* memory.c & swap.c*/

#define free_page(addr) free_pages((addr),0)
extern void FASTCALL(free_pages(unsigned long addr, unsigned long order));
extern void FASTCALL(__free_page(struct page *));

extern void show_free_areas(void);
extern unsigned long put_dirty_page(struct task_struct * tsk,unsigned long page,
	unsigned long address);

extern void free_page_tables(struct mm_struct * mm);
extern void clear_page_tables(struct mm_struct *, unsigned long, int);
extern int new_page_tables(struct task_struct * tsk);

extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma);
extern int remap_page_range(unsigned long from, unsigned long to, unsigned long size, pgprot_t prot);
extern int zeromap_page_range(unsigned long from, unsigned long size, pgprot_t prot);

extern void vmtruncate(struct inode * inode, unsigned long offset);
extern int handle_mm_fault(struct task_struct *tsk,struct vm_area_struct *vma, unsigned long address, int write_access);
extern int make_pages_present(unsigned long addr, unsigned long end);

extern int pgt_cache_water[2];
extern int check_pgt_cache(void);

extern unsigned long paging_init(unsigned long start_mem, unsigned long end_mem);
extern void mem_init(unsigned long start_mem, unsigned long end_mem);
extern void show_mem(void);
extern void si_meminfo(struct sysinfo * val);

/* mmap.c */
extern void vma_init(void);
extern void merge_segments(struct mm_struct *, unsigned long, unsigned long);
extern void insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
extern void build_mmap_avl(struct mm_struct *);
extern void exit_mmap(struct mm_struct *);
extern unsigned long get_unmapped_area(unsigned long, unsigned long);

extern unsigned long do_mmap(struct file *, unsigned long, unsigned long,
	unsigned long, unsigned long, unsigned long);
extern int do_munmap(unsigned long, size_t);

/* filemap.c */
extern void remove_inode_page(struct page *);
extern unsigned long page_unuse(struct page *);
extern int shrink_mmap(int, int);
extern void truncate_inode_pages(struct inode *, unsigned long);
extern unsigned long get_cached_page(struct inode *, unsigned long, int);
extern void put_cached_page(unsigned long);

/*
 * GFP bitmasks..
 */
#define __GFP_WAIT	0x01
#define __GFP_LOW	0x02
#define __GFP_MED	0x04
#define __GFP_HIGH	0x08
#define __GFP_IO	0x10
#define __GFP_SWAP	0x20

#define __GFP_DMA	0x80

#define GFP_BUFFER	(__GFP_LOW | __GFP_WAIT)
#define GFP_ATOMIC	(__GFP_HIGH)
#define GFP_USER	(__GFP_LOW | __GFP_WAIT | __GFP_IO)
#define GFP_KERNEL	(__GFP_MED | __GFP_WAIT | __GFP_IO)
#define GFP_NFS		(__GFP_HIGH | __GFP_WAIT | __GFP_IO)
#define GFP_KSWAPD	(__GFP_IO | __GFP_SWAP)

/* Flag - indicates that the buffer will be suitable for DMA.  Ignored on some
   platforms, used as appropriate on others */

#define GFP_DMA		__GFP_DMA

/* vma is the first one with  address < vma->vm_end,
 * and even  address < vma->vm_start. Have to extend vma. */
static inline int expand_stack(struct vm_area_struct * vma, unsigned long address)
{
	unsigned long grow;

	address &= PAGE_MASK;
	grow = vma->vm_start - address;
	if ((vma->vm_end - address
	    > current->rlim[RLIMIT_STACK].rlim_cur) ||
	    ((current->rlim[RLIMIT_AS].rlim_cur < RLIM_INFINITY) &&
	    ((vma->vm_mm->total_vm << PAGE_SHIFT) + grow
	    > current->rlim[RLIMIT_AS].rlim_cur)))
		return -ENOMEM;
	vma->vm_start = address;
	vma->vm_offset -= grow;
	vma->vm_mm->total_vm += grow >> PAGE_SHIFT;
	if (vma->vm_flags & VM_LOCKED)
		vma->vm_mm->locked_vm += grow >> PAGE_SHIFT;
	return 0;
}

/* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);

/* Look up the first VMA which intersects the interval start_addr..end_addr-1,
   NULL if none.  Assume start_addr < end_addr. */
static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
{
	struct vm_area_struct * vma = find_vma(mm,start_addr);

	if (vma && end_addr <= vma->vm_start)
		vma = NULL;
	return vma;
}

#define buffer_under_min()	((buffermem >> PAGE_SHIFT) * 100 < \
				buffer_mem.min_percent * num_physpages)
#define pgcache_under_min()	(page_cache_size * 100 < \
				page_cache.min_percent * num_physpages)

#endif /* __KERNEL__ */

#endif