Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/backing-dev.h | |
3 | * | |
4 | * low-level device information and state which is propagated up through | |
5 | * to high-level code. | |
6 | */ | |
7 | ||
8 | #ifndef _LINUX_BACKING_DEV_H | |
9 | #define _LINUX_BACKING_DEV_H | |
10 | ||
b2e8fb6e PZ |
11 | #include <linux/percpu_counter.h> |
12 | #include <linux/log2.h> | |
04fbfdc1 | 13 | #include <linux/proportions.h> |
cf0ca9fe | 14 | #include <linux/kernel.h> |
e4ad08fe | 15 | #include <linux/fs.h> |
03ba3782 | 16 | #include <linux/sched.h> |
31373d09 | 17 | #include <linux/timer.h> |
03ba3782 | 18 | #include <linux/writeback.h> |
1da177e4 LT |
19 | #include <asm/atomic.h> |
20 | ||
3fcfab16 | 21 | struct page; |
cf0ca9fe | 22 | struct device; |
76f1418b | 23 | struct dentry; |
3fcfab16 | 24 | |
1da177e4 LT |
25 | /* |
26 | * Bits in backing_dev_info.state | |
27 | */ | |
28 | enum bdi_state { | |
03ba3782 JA |
29 | BDI_pending, /* On its way to being activated */ |
30 | BDI_wb_alloc, /* Default embedded wb allocated */ | |
1faa16d2 JA |
31 | BDI_async_congested, /* The async (write) queue is getting full */ |
32 | BDI_sync_congested, /* The sync queue is getting full */ | |
500b067c | 33 | BDI_registered, /* bdi_register() was done */ |
1da177e4 LT |
34 | BDI_unused, /* Available bits start here */ |
35 | }; | |
36 | ||
37 | typedef int (congested_fn)(void *, int); | |
38 | ||
b2e8fb6e | 39 | enum bdi_stat_item { |
c9e51e41 | 40 | BDI_RECLAIMABLE, |
69cb51d1 | 41 | BDI_WRITEBACK, |
b2e8fb6e PZ |
42 | NR_BDI_STAT_ITEMS |
43 | }; | |
44 | ||
45 | #define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) | |
46 | ||
03ba3782 | 47 | struct bdi_writeback { |
03ba3782 JA |
48 | struct backing_dev_info *bdi; /* our parent bdi */ |
49 | unsigned int nr; | |
50 | ||
51 | unsigned long last_old_flush; /* last old data flush */ | |
52 | ||
6f904ff0 | 53 | struct task_struct *task; /* writeback thread */ |
03ba3782 JA |
54 | struct list_head b_dirty; /* dirty inodes */ |
55 | struct list_head b_io; /* parked for writeback */ | |
56 | struct list_head b_more_io; /* parked for more writeback */ | |
57 | }; | |
58 | ||
1da177e4 | 59 | struct backing_dev_info { |
66f3b8e2 | 60 | struct list_head bdi_list; |
1da177e4 LT |
61 | unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ |
62 | unsigned long state; /* Always use atomic bitops on this */ | |
63 | unsigned int capabilities; /* Device capabilities */ | |
64 | congested_fn *congested_fn; /* Function pointer if device is md/dm */ | |
65 | void *congested_data; /* Pointer to aux data for congested func */ | |
66 | void (*unplug_io_fn)(struct backing_dev_info *, struct page *); | |
67 | void *unplug_io_data; | |
b2e8fb6e | 68 | |
d993831f JA |
69 | char *name; |
70 | ||
b2e8fb6e | 71 | struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; |
04fbfdc1 PZ |
72 | |
73 | struct prop_local_percpu completions; | |
74 | int dirty_exceeded; | |
cf0ca9fe | 75 | |
189d3c4a | 76 | unsigned int min_ratio; |
a42dde04 | 77 | unsigned int max_ratio, max_prop_frac; |
189d3c4a | 78 | |
03ba3782 | 79 | struct bdi_writeback wb; /* default writeback info for this bdi */ |
c1955ce3 | 80 | spinlock_t wb_lock; /* protects work_list */ |
76f1418b | 81 | |
03ba3782 JA |
82 | struct list_head work_list; |
83 | ||
84 | struct device *dev; | |
66f3b8e2 | 85 | |
31373d09 MG |
86 | struct timer_list laptop_mode_wb_timer; |
87 | ||
76f1418b MS |
88 | #ifdef CONFIG_DEBUG_FS |
89 | struct dentry *debug_dir; | |
90 | struct dentry *debug_stats; | |
91 | #endif | |
1da177e4 LT |
92 | }; |
93 | ||
b2e8fb6e PZ |
94 | int bdi_init(struct backing_dev_info *bdi); |
95 | void bdi_destroy(struct backing_dev_info *bdi); | |
96 | ||
cf0ca9fe PZ |
97 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
98 | const char *fmt, ...); | |
99 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); | |
100 | void bdi_unregister(struct backing_dev_info *bdi); | |
c3c53206 | 101 | int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int); |
c5444198 CH |
102 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages); |
103 | void bdi_start_background_writeback(struct backing_dev_info *bdi); | |
08243900 | 104 | int bdi_writeback_thread(void *data); |
03ba3782 | 105 | int bdi_has_dirty_io(struct backing_dev_info *bdi); |
6423104b | 106 | void bdi_arm_supers_timer(void); |
cf0ca9fe | 107 | |
03ba3782 | 108 | extern spinlock_t bdi_lock; |
66f3b8e2 JA |
109 | extern struct list_head bdi_list; |
110 | ||
03ba3782 JA |
111 | static inline int wb_has_dirty_io(struct bdi_writeback *wb) |
112 | { | |
113 | return !list_empty(&wb->b_dirty) || | |
114 | !list_empty(&wb->b_io) || | |
115 | !list_empty(&wb->b_more_io); | |
116 | } | |
117 | ||
b2e8fb6e PZ |
118 | static inline void __add_bdi_stat(struct backing_dev_info *bdi, |
119 | enum bdi_stat_item item, s64 amount) | |
120 | { | |
121 | __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); | |
122 | } | |
123 | ||
124 | static inline void __inc_bdi_stat(struct backing_dev_info *bdi, | |
125 | enum bdi_stat_item item) | |
126 | { | |
127 | __add_bdi_stat(bdi, item, 1); | |
128 | } | |
129 | ||
130 | static inline void inc_bdi_stat(struct backing_dev_info *bdi, | |
131 | enum bdi_stat_item item) | |
132 | { | |
133 | unsigned long flags; | |
134 | ||
135 | local_irq_save(flags); | |
136 | __inc_bdi_stat(bdi, item); | |
137 | local_irq_restore(flags); | |
138 | } | |
139 | ||
140 | static inline void __dec_bdi_stat(struct backing_dev_info *bdi, | |
141 | enum bdi_stat_item item) | |
142 | { | |
143 | __add_bdi_stat(bdi, item, -1); | |
144 | } | |
145 | ||
146 | static inline void dec_bdi_stat(struct backing_dev_info *bdi, | |
147 | enum bdi_stat_item item) | |
148 | { | |
149 | unsigned long flags; | |
150 | ||
151 | local_irq_save(flags); | |
152 | __dec_bdi_stat(bdi, item); | |
153 | local_irq_restore(flags); | |
154 | } | |
155 | ||
156 | static inline s64 bdi_stat(struct backing_dev_info *bdi, | |
157 | enum bdi_stat_item item) | |
158 | { | |
159 | return percpu_counter_read_positive(&bdi->bdi_stat[item]); | |
160 | } | |
161 | ||
162 | static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi, | |
163 | enum bdi_stat_item item) | |
164 | { | |
165 | return percpu_counter_sum_positive(&bdi->bdi_stat[item]); | |
166 | } | |
167 | ||
168 | static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, | |
169 | enum bdi_stat_item item) | |
e0bf68dd | 170 | { |
b2e8fb6e PZ |
171 | s64 sum; |
172 | unsigned long flags; | |
173 | ||
174 | local_irq_save(flags); | |
175 | sum = __bdi_stat_sum(bdi, item); | |
176 | local_irq_restore(flags); | |
177 | ||
178 | return sum; | |
e0bf68dd PZ |
179 | } |
180 | ||
dd5656e5 MS |
181 | extern void bdi_writeout_inc(struct backing_dev_info *bdi); |
182 | ||
b2e8fb6e PZ |
183 | /* |
184 | * maximal error of a stat counter. | |
185 | */ | |
186 | static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) | |
e0bf68dd | 187 | { |
b2e8fb6e PZ |
188 | #ifdef CONFIG_SMP |
189 | return nr_cpu_ids * BDI_STAT_BATCH; | |
190 | #else | |
191 | return 1; | |
192 | #endif | |
e0bf68dd | 193 | } |
1da177e4 | 194 | |
189d3c4a | 195 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 196 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 197 | |
1da177e4 LT |
198 | /* |
199 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
200 | * |
201 | * The first three flags control whether dirty pages will contribute to the | |
202 | * VM's accounting and whether writepages() should be called for dirty pages | |
203 | * (something that would not, for example, be appropriate for ramfs) | |
204 | * | |
205 | * WARNING: these flags are closely related and should not normally be | |
206 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
207 | * three flags into a single convenience macro. | |
208 | * | |
209 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
210 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
211 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
212 | * | |
213 | * These flags let !MMU mmap() govern direct device mapping vs immediate | |
214 | * copying more easily for MAP_PRIVATE, especially for ROM filesystems. | |
215 | * | |
216 | * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE) | |
217 | * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED) | |
218 | * BDI_CAP_READ_MAP: Can be mapped for reading | |
219 | * BDI_CAP_WRITE_MAP: Can be mapped for writing | |
220 | * BDI_CAP_EXEC_MAP: Can be mapped for execution | |
4f98a2fe RR |
221 | * |
222 | * BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed. | |
1da177e4 | 223 | */ |
e4ad08fe MS |
224 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
225 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
226 | #define BDI_CAP_MAP_COPY 0x00000004 | |
227 | #define BDI_CAP_MAP_DIRECT 0x00000008 | |
228 | #define BDI_CAP_READ_MAP 0x00000010 | |
229 | #define BDI_CAP_WRITE_MAP 0x00000020 | |
230 | #define BDI_CAP_EXEC_MAP 0x00000040 | |
231 | #define BDI_CAP_NO_ACCT_WB 0x00000080 | |
4f98a2fe | 232 | #define BDI_CAP_SWAP_BACKED 0x00000100 |
e4ad08fe | 233 | |
1da177e4 LT |
234 | #define BDI_CAP_VMFLAGS \ |
235 | (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) | |
236 | ||
e4ad08fe MS |
237 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
238 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
239 | ||
1da177e4 LT |
240 | #if defined(VM_MAYREAD) && \ |
241 | (BDI_CAP_READ_MAP != VM_MAYREAD || \ | |
242 | BDI_CAP_WRITE_MAP != VM_MAYWRITE || \ | |
243 | BDI_CAP_EXEC_MAP != VM_MAYEXEC) | |
244 | #error please change backing_dev_info::capabilities flags | |
245 | #endif | |
246 | ||
247 | extern struct backing_dev_info default_backing_dev_info; | |
5129a469 | 248 | extern struct backing_dev_info noop_backing_dev_info; |
1da177e4 LT |
249 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page); |
250 | ||
1da177e4 | 251 | int writeback_in_progress(struct backing_dev_info *bdi); |
1da177e4 LT |
252 | |
253 | static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) | |
254 | { | |
255 | if (bdi->congested_fn) | |
256 | return bdi->congested_fn(bdi->congested_data, bdi_bits); | |
257 | return (bdi->state & bdi_bits); | |
258 | } | |
259 | ||
260 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
261 | { | |
1faa16d2 | 262 | return bdi_congested(bdi, 1 << BDI_sync_congested); |
1da177e4 LT |
263 | } |
264 | ||
265 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
266 | { | |
1faa16d2 | 267 | return bdi_congested(bdi, 1 << BDI_async_congested); |
1da177e4 LT |
268 | } |
269 | ||
270 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
271 | { | |
1faa16d2 JA |
272 | return bdi_congested(bdi, (1 << BDI_sync_congested) | |
273 | (1 << BDI_async_congested)); | |
1da177e4 LT |
274 | } |
275 | ||
373c0a7e TM |
276 | enum { |
277 | BLK_RW_ASYNC = 0, | |
278 | BLK_RW_SYNC = 1, | |
279 | }; | |
280 | ||
8aa7e847 JA |
281 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync); |
282 | void set_bdi_congested(struct backing_dev_info *bdi, int sync); | |
283 | long congestion_wait(int sync, long timeout); | |
3fcfab16 | 284 | |
1da177e4 | 285 | |
e4ad08fe MS |
286 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
287 | { | |
288 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
289 | } | |
290 | ||
291 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
292 | { | |
293 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
294 | } | |
1da177e4 | 295 | |
e4ad08fe MS |
296 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
297 | { | |
298 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
299 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
300 | BDI_CAP_NO_WRITEBACK)); | |
301 | } | |
1da177e4 | 302 | |
4f98a2fe RR |
303 | static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi) |
304 | { | |
305 | return bdi->capabilities & BDI_CAP_SWAP_BACKED; | |
306 | } | |
307 | ||
03ba3782 JA |
308 | static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi) |
309 | { | |
310 | return bdi == &default_backing_dev_info; | |
311 | } | |
312 | ||
e4ad08fe MS |
313 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
314 | { | |
315 | return bdi_cap_writeback_dirty(mapping->backing_dev_info); | |
316 | } | |
1da177e4 | 317 | |
e4ad08fe MS |
318 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
319 | { | |
320 | return bdi_cap_account_dirty(mapping->backing_dev_info); | |
321 | } | |
1da177e4 | 322 | |
4f98a2fe RR |
323 | static inline bool mapping_cap_swap_backed(struct address_space *mapping) |
324 | { | |
325 | return bdi_cap_swap_backed(mapping->backing_dev_info); | |
326 | } | |
327 | ||
03ba3782 JA |
328 | static inline int bdi_sched_wait(void *word) |
329 | { | |
330 | schedule(); | |
331 | return 0; | |
332 | } | |
333 | ||
b9d128f1 JA |
334 | static inline void blk_run_backing_dev(struct backing_dev_info *bdi, |
335 | struct page *page) | |
336 | { | |
337 | if (bdi && bdi->unplug_io_fn) | |
338 | bdi->unplug_io_fn(bdi, page); | |
339 | } | |
340 | ||
341 | static inline void blk_run_address_space(struct address_space *mapping) | |
342 | { | |
343 | if (mapping) | |
344 | blk_run_backing_dev(mapping->backing_dev_info, NULL); | |
345 | } | |
346 | ||
1da177e4 | 347 | #endif /* _LINUX_BACKING_DEV_H */ |