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
|
/*
* Macros for manipulating and testing page->flags
*/
#ifndef PAGE_FLAGS_H
#define PAGE_FLAGS_H
#include <linux/percpu.h>
#include <linux/cache.h>
#include <asm/pgtable.h>
/*
* Various page->flags bits:
*
* PG_reserved is set for special pages, which can never be swapped out. Some
* of them might not even exist (eg empty_bad_page)...
*
* The PG_private bitflag is set if page->private contains a valid value.
*
* During disk I/O, PG_locked is used. This bit is set before I/O and
* reset when I/O completes. page_waitqueue(page) 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.
*
* 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 (mapping,
* index) hash table. This referenced bit, together with the referenced bit
* in the page tables, is used to manipulate page->age and move the page across
* the active, inactive_dirty and inactive_clean lists.
*
* Note that the referenced bit, the page->lru list_head and the active,
* inactive_dirty and inactive_clean lists are protected by the
* zone->lru_lock, and *NOT* by the usual PG_locked bit!
*
* PG_error is set to indicate that an I/O error occurred on this page.
*
* PG_arch_1 is an architecture specific page state bit. The generic code
* guarantees that this bit is cleared for a page when it first is entered into
* the page cache.
*
* PG_highmem pages are not permanently mapped into the kernel virtual address
* space, they need to be kmapped separately for doing IO on the pages. The
* struct page (these bits with information) are always mapped into kernel
* address space...
*/
/*
* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
* locked- and dirty-page accounting. The top eight bits of page->flags are
* used for page->zone, so putting flag bits there doesn't work.
*/
#define PG_locked 0 /* Page is locked. Don't touch. */
#define PG_error 1
#define PG_referenced 2
#define PG_uptodate 3
#define PG_dirty 4
#define PG_lru 5
#define PG_active 6
#define PG_slab 7 /* slab debug (Suparna wants this) */
#define PG_checked 8 /* kill me in 2.5.<early>. */
#define PG_arch_1 9
#define PG_reserved 10
#define PG_private 11 /* Has something at ->private */
#define PG_writeback 12 /* Page is under writeback */
#define PG_nosave 13 /* Used for system suspend/resume */
#define PG_compound 14 /* Part of a compound page */
#define PG_swapcache 15 /* Swap page: swp_entry_t in private */
#define PG_mappedtodisk 16 /* Has blocks allocated on-disk */
#define PG_reclaim 17 /* To be reclaimed asap */
#define PG_nosave_free 18 /* Free, should not be written */
#define PG_uncached 19 /* Page has been mapped as uncached */
/*
* Global page accounting. One instance per CPU. Only unsigned longs are
* allowed.
*
* - Fields can be modified with xxx_page_state and xxx_page_state_zone at
* any time safely (which protects the instance from modification by
* interrupt.
* - The __xxx_page_state variants can be used safely when interrupts are
* disabled.
* - The __xxx_page_state variants can be used if the field is only
* modified from process context, or only modified from interrupt context.
* In this case, the field should be commented here.
*/
struct page_state {
unsigned long nr_dirty; /* Dirty writeable pages */
unsigned long nr_writeback; /* Pages under writeback */
unsigned long nr_unstable; /* NFS unstable pages */
unsigned long nr_page_table_pages;/* Pages used for pagetables */
unsigned long nr_mapped; /* mapped into pagetables.
* only modified from process context */
unsigned long nr_slab; /* In slab */
#define GET_PAGE_STATE_LAST nr_slab
/*
* The below are zeroed by get_page_state(). Use get_full_page_state()
* to add up all these.
*/
unsigned long pgpgin; /* Disk reads */
unsigned long pgpgout; /* Disk writes */
unsigned long pswpin; /* swap reads */
unsigned long pswpout; /* swap writes */
unsigned long pgalloc_high; /* page allocations */
unsigned long pgalloc_normal;
unsigned long pgalloc_dma32;
unsigned long pgalloc_dma;
unsigned long pgfree; /* page freeings */
unsigned long pgactivate; /* pages moved inactive->active */
unsigned long pgdeactivate; /* pages moved active->inactive */
unsigned long pgfault; /* faults (major+minor) */
unsigned long pgmajfault; /* faults (major only) */
unsigned long pgrefill_high; /* inspected in refill_inactive_zone */
unsigned long pgrefill_normal;
unsigned long pgrefill_dma32;
unsigned long pgrefill_dma;
unsigned long pgsteal_high; /* total highmem pages reclaimed */
unsigned long pgsteal_normal;
unsigned long pgsteal_dma32;
unsigned long pgsteal_dma;
unsigned long pgscan_kswapd_high;/* total highmem pages scanned */
unsigned long pgscan_kswapd_normal;
unsigned long pgscan_kswapd_dma32;
unsigned long pgscan_kswapd_dma;
unsigned long pgscan_direct_high;/* total highmem pages scanned */
unsigned long pgscan_direct_normal;
unsigned long pgscan_direct_dma32;
unsigned long pgscan_direct_dma;
unsigned long pginodesteal; /* pages reclaimed via inode freeing */
unsigned long slabs_scanned; /* slab objects scanned */
unsigned long kswapd_steal; /* pages reclaimed by kswapd */
unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */
unsigned long pageoutrun; /* kswapd's calls to page reclaim */
unsigned long allocstall; /* direct reclaim calls */
unsigned long pgrotated; /* pages rotated to tail of the LRU */
unsigned long nr_bounce; /* pages for bounce buffers */
};
extern void get_page_state(struct page_state *ret);
extern void get_page_state_node(struct page_state *ret, int node);
extern void get_full_page_state(struct page_state *ret);
extern unsigned long read_page_state_offset(unsigned long offset);
extern void mod_page_state_offset(unsigned long offset, unsigned long delta);
extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
#define read_page_state(member) \
read_page_state_offset(offsetof(struct page_state, member))
#define mod_page_state(member, delta) \
mod_page_state_offset(offsetof(struct page_state, member), (delta))
#define __mod_page_state(member, delta) \
__mod_page_state_offset(offsetof(struct page_state, member), (delta))
#define inc_page_state(member) mod_page_state(member, 1UL)
#define dec_page_state(member) mod_page_state(member, 0UL - 1)
#define add_page_state(member,delta) mod_page_state(member, (delta))
#define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta))
#define __inc_page_state(member) __mod_page_state(member, 1UL)
#define __dec_page_state(member) __mod_page_state(member, 0UL - 1)
#define __add_page_state(member,delta) __mod_page_state(member, (delta))
#define __sub_page_state(member,delta) __mod_page_state(member, 0UL - (delta))
#define page_state(member) (*__page_state(offsetof(struct page_state, member)))
#define state_zone_offset(zone, member) \
({ \
unsigned offset; \
if (is_highmem(zone)) \
offset = offsetof(struct page_state, member##_high); \
else if (is_normal(zone)) \
offset = offsetof(struct page_state, member##_normal); \
else if (is_dma32(zone)) \
offset = offsetof(struct page_state, member##_dma32); \
else \
offset = offsetof(struct page_state, member##_dma); \
offset; \
})
#define __mod_page_state_zone(zone, member, delta) \
do { \
__mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
} while (0)
#define mod_page_state_zone(zone, member, delta) \
do { \
mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
} while (0)
/*
* Manipulation of page state flags
*/
#define PageLocked(page) \
test_bit(PG_locked, &(page)->flags)
#define SetPageLocked(page) \
set_bit(PG_locked, &(page)->flags)
#define TestSetPageLocked(page) \
test_and_set_bit(PG_locked, &(page)->flags)
#define ClearPageLocked(page) \
clear_bit(PG_locked, &(page)->flags)
#define TestClearPageLocked(page) \
test_and_clear_bit(PG_locked, &(page)->flags)
#define PageError(page) test_bit(PG_error, &(page)->flags)
#define SetPageError(page) set_bit(PG_error, &(page)->flags)
#define ClearPageError(page) clear_bit(PG_error, &(page)->flags)
#define PageReferenced(page) test_bit(PG_referenced, &(page)->flags)
#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
#define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags)
#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags)
#ifndef SetPageUptodate
#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
#endif
#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
#define PageDirty(page) test_bit(PG_dirty, &(page)->flags)
#define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags)
#define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags)
#define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags)
#define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags)
#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
#define PageLRU(page) test_bit(PG_lru, &(page)->flags)
#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
#define ClearPageLRU(page) clear_bit(PG_lru, &(page)->flags)
#define PageActive(page) test_bit(PG_active, &(page)->flags)
#define SetPageActive(page) set_bit(PG_active, &(page)->flags)
#define ClearPageActive(page) clear_bit(PG_active, &(page)->flags)
#define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags)
#define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags)
#define PageSlab(page) test_bit(PG_slab, &(page)->flags)
#define SetPageSlab(page) set_bit(PG_slab, &(page)->flags)
#define ClearPageSlab(page) clear_bit(PG_slab, &(page)->flags)
#define TestClearPageSlab(page) test_and_clear_bit(PG_slab, &(page)->flags)
#define TestSetPageSlab(page) test_and_set_bit(PG_slab, &(page)->flags)
#ifdef CONFIG_HIGHMEM
#define PageHighMem(page) is_highmem(page_zone(page))
#else
#define PageHighMem(page) 0 /* needed to optimize away at compile time */
#endif
#define PageChecked(page) test_bit(PG_checked, &(page)->flags)
#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
#define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags)
#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
#define PagePrivate(page) test_bit(PG_private, &(page)->flags)
#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
#define SetPageWriteback(page) \
do { \
if (!test_and_set_bit(PG_writeback, \
&(page)->flags)) \
inc_page_state(nr_writeback); \
} while (0)
#define TestSetPageWriteback(page) \
({ \
int ret; \
ret = test_and_set_bit(PG_writeback, \
&(page)->flags); \
if (!ret) \
inc_page_state(nr_writeback); \
ret; \
})
#define ClearPageWriteback(page) \
do { \
if (test_and_clear_bit(PG_writeback, \
&(page)->flags)) \
dec_page_state(nr_writeback); \
} while (0)
#define TestClearPageWriteback(page) \
({ \
int ret; \
ret = test_and_clear_bit(PG_writeback, \
&(page)->flags); \
if (ret) \
dec_page_state(nr_writeback); \
ret; \
})
#define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
#define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
#define PageCompound(page) test_bit(PG_compound, &(page)->flags)
#define SetPageCompound(page) set_bit(PG_compound, &(page)->flags)
#define ClearPageCompound(page) clear_bit(PG_compound, &(page)->flags)
#ifdef CONFIG_SWAP
#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)
#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
#else
#define PageSwapCache(page) 0
#endif
#define PageUncached(page) test_bit(PG_uncached, &(page)->flags)
#define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags)
#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
struct page; /* forward declaration */
int test_clear_page_dirty(struct page *page);
int test_clear_page_writeback(struct page *page);
int test_set_page_writeback(struct page *page);
static inline void clear_page_dirty(struct page *page)
{
test_clear_page_dirty(page);
}
static inline void set_page_writeback(struct page *page)
{
test_set_page_writeback(page);
}
#endif /* PAGE_FLAGS_H */
|
