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 */ |
81d73a32 | 34 | BDI_writeback_running, /* Writeback is in progress */ |
1da177e4 LT |
35 | BDI_unused, /* Available bits start here */ |
36 | }; | |
37 | ||
38 | typedef int (congested_fn)(void *, int); | |
39 | ||
b2e8fb6e | 40 | enum bdi_stat_item { |
c9e51e41 | 41 | BDI_RECLAIMABLE, |
69cb51d1 | 42 | BDI_WRITEBACK, |
f7d2b1ec | 43 | BDI_WRITTEN, |
b2e8fb6e PZ |
44 | NR_BDI_STAT_ITEMS |
45 | }; | |
46 | ||
47 | #define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) | |
48 | ||
03ba3782 | 49 | struct bdi_writeback { |
ecd58403 | 50 | struct backing_dev_info *bdi; /* our parent bdi */ |
03ba3782 JA |
51 | unsigned int nr; |
52 | ||
ecd58403 AB |
53 | unsigned long last_old_flush; /* last old data flush */ |
54 | unsigned long last_active; /* last time bdi thread was active */ | |
03ba3782 | 55 | |
ecd58403 | 56 | struct task_struct *task; /* writeback thread */ |
6467716a | 57 | struct timer_list wakeup_timer; /* used for delayed bdi thread wakeup */ |
ecd58403 AB |
58 | struct list_head b_dirty; /* dirty inodes */ |
59 | struct list_head b_io; /* parked for writeback */ | |
60 | struct list_head b_more_io; /* parked for more writeback */ | |
f758eeab | 61 | spinlock_t list_lock; /* protects the b_* lists */ |
03ba3782 JA |
62 | }; |
63 | ||
1da177e4 | 64 | struct backing_dev_info { |
66f3b8e2 | 65 | struct list_head bdi_list; |
1da177e4 LT |
66 | unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ |
67 | unsigned long state; /* Always use atomic bitops on this */ | |
68 | unsigned int capabilities; /* Device capabilities */ | |
69 | congested_fn *congested_fn; /* Function pointer if device is md/dm */ | |
70 | void *congested_data; /* Pointer to aux data for congested func */ | |
b2e8fb6e | 71 | |
d993831f JA |
72 | char *name; |
73 | ||
b2e8fb6e | 74 | struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; |
04fbfdc1 PZ |
75 | |
76 | struct prop_local_percpu completions; | |
77 | int dirty_exceeded; | |
cf0ca9fe | 78 | |
189d3c4a | 79 | unsigned int min_ratio; |
a42dde04 | 80 | unsigned int max_ratio, max_prop_frac; |
189d3c4a | 81 | |
03ba3782 | 82 | struct bdi_writeback wb; /* default writeback info for this bdi */ |
c1955ce3 | 83 | spinlock_t wb_lock; /* protects work_list */ |
76f1418b | 84 | |
03ba3782 JA |
85 | struct list_head work_list; |
86 | ||
87 | struct device *dev; | |
66f3b8e2 | 88 | |
31373d09 MG |
89 | struct timer_list laptop_mode_wb_timer; |
90 | ||
76f1418b MS |
91 | #ifdef CONFIG_DEBUG_FS |
92 | struct dentry *debug_dir; | |
93 | struct dentry *debug_stats; | |
94 | #endif | |
1da177e4 LT |
95 | }; |
96 | ||
b2e8fb6e PZ |
97 | int bdi_init(struct backing_dev_info *bdi); |
98 | void bdi_destroy(struct backing_dev_info *bdi); | |
99 | ||
cf0ca9fe PZ |
100 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
101 | const char *fmt, ...); | |
102 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); | |
103 | void bdi_unregister(struct backing_dev_info *bdi); | |
c3c53206 | 104 | int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int); |
c5444198 CH |
105 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages); |
106 | void bdi_start_background_writeback(struct backing_dev_info *bdi); | |
08243900 | 107 | int bdi_writeback_thread(void *data); |
03ba3782 | 108 | int bdi_has_dirty_io(struct backing_dev_info *bdi); |
6423104b | 109 | void bdi_arm_supers_timer(void); |
6467716a | 110 | void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi); |
f758eeab | 111 | void bdi_lock_two(struct bdi_writeback *wb1, struct bdi_writeback *wb2); |
cf0ca9fe | 112 | |
03ba3782 | 113 | extern spinlock_t bdi_lock; |
66f3b8e2 | 114 | extern struct list_head bdi_list; |
92c09c04 | 115 | extern struct list_head bdi_pending_list; |
66f3b8e2 | 116 | |
03ba3782 JA |
117 | static inline int wb_has_dirty_io(struct bdi_writeback *wb) |
118 | { | |
119 | return !list_empty(&wb->b_dirty) || | |
120 | !list_empty(&wb->b_io) || | |
121 | !list_empty(&wb->b_more_io); | |
122 | } | |
123 | ||
b2e8fb6e PZ |
124 | static inline void __add_bdi_stat(struct backing_dev_info *bdi, |
125 | enum bdi_stat_item item, s64 amount) | |
126 | { | |
127 | __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); | |
128 | } | |
129 | ||
130 | static inline void __inc_bdi_stat(struct backing_dev_info *bdi, | |
131 | enum bdi_stat_item item) | |
132 | { | |
133 | __add_bdi_stat(bdi, item, 1); | |
134 | } | |
135 | ||
136 | static inline void inc_bdi_stat(struct backing_dev_info *bdi, | |
137 | enum bdi_stat_item item) | |
138 | { | |
139 | unsigned long flags; | |
140 | ||
141 | local_irq_save(flags); | |
142 | __inc_bdi_stat(bdi, item); | |
143 | local_irq_restore(flags); | |
144 | } | |
145 | ||
146 | static inline void __dec_bdi_stat(struct backing_dev_info *bdi, | |
147 | enum bdi_stat_item item) | |
148 | { | |
149 | __add_bdi_stat(bdi, item, -1); | |
150 | } | |
151 | ||
152 | static inline void dec_bdi_stat(struct backing_dev_info *bdi, | |
153 | enum bdi_stat_item item) | |
154 | { | |
155 | unsigned long flags; | |
156 | ||
157 | local_irq_save(flags); | |
158 | __dec_bdi_stat(bdi, item); | |
159 | local_irq_restore(flags); | |
160 | } | |
161 | ||
162 | static inline s64 bdi_stat(struct backing_dev_info *bdi, | |
163 | enum bdi_stat_item item) | |
164 | { | |
165 | return percpu_counter_read_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) | |
170 | { | |
171 | return percpu_counter_sum_positive(&bdi->bdi_stat[item]); | |
172 | } | |
173 | ||
174 | static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, | |
175 | enum bdi_stat_item item) | |
e0bf68dd | 176 | { |
b2e8fb6e PZ |
177 | s64 sum; |
178 | unsigned long flags; | |
179 | ||
180 | local_irq_save(flags); | |
181 | sum = __bdi_stat_sum(bdi, item); | |
182 | local_irq_restore(flags); | |
183 | ||
184 | return sum; | |
e0bf68dd PZ |
185 | } |
186 | ||
dd5656e5 MS |
187 | extern void bdi_writeout_inc(struct backing_dev_info *bdi); |
188 | ||
b2e8fb6e PZ |
189 | /* |
190 | * maximal error of a stat counter. | |
191 | */ | |
192 | static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) | |
e0bf68dd | 193 | { |
b2e8fb6e PZ |
194 | #ifdef CONFIG_SMP |
195 | return nr_cpu_ids * BDI_STAT_BATCH; | |
196 | #else | |
197 | return 1; | |
198 | #endif | |
e0bf68dd | 199 | } |
1da177e4 | 200 | |
189d3c4a | 201 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 202 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 203 | |
1da177e4 LT |
204 | /* |
205 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
206 | * |
207 | * The first three flags control whether dirty pages will contribute to the | |
208 | * VM's accounting and whether writepages() should be called for dirty pages | |
209 | * (something that would not, for example, be appropriate for ramfs) | |
210 | * | |
211 | * WARNING: these flags are closely related and should not normally be | |
212 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
213 | * three flags into a single convenience macro. | |
214 | * | |
215 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
216 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
217 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
218 | * | |
219 | * These flags let !MMU mmap() govern direct device mapping vs immediate | |
220 | * copying more easily for MAP_PRIVATE, especially for ROM filesystems. | |
221 | * | |
222 | * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE) | |
223 | * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED) | |
224 | * BDI_CAP_READ_MAP: Can be mapped for reading | |
225 | * BDI_CAP_WRITE_MAP: Can be mapped for writing | |
226 | * BDI_CAP_EXEC_MAP: Can be mapped for execution | |
4f98a2fe RR |
227 | * |
228 | * BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed. | |
1da177e4 | 229 | */ |
e4ad08fe MS |
230 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
231 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
232 | #define BDI_CAP_MAP_COPY 0x00000004 | |
233 | #define BDI_CAP_MAP_DIRECT 0x00000008 | |
234 | #define BDI_CAP_READ_MAP 0x00000010 | |
235 | #define BDI_CAP_WRITE_MAP 0x00000020 | |
236 | #define BDI_CAP_EXEC_MAP 0x00000040 | |
237 | #define BDI_CAP_NO_ACCT_WB 0x00000080 | |
4f98a2fe | 238 | #define BDI_CAP_SWAP_BACKED 0x00000100 |
e4ad08fe | 239 | |
1da177e4 LT |
240 | #define BDI_CAP_VMFLAGS \ |
241 | (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) | |
242 | ||
e4ad08fe MS |
243 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
244 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
245 | ||
1da177e4 LT |
246 | #if defined(VM_MAYREAD) && \ |
247 | (BDI_CAP_READ_MAP != VM_MAYREAD || \ | |
248 | BDI_CAP_WRITE_MAP != VM_MAYWRITE || \ | |
249 | BDI_CAP_EXEC_MAP != VM_MAYEXEC) | |
250 | #error please change backing_dev_info::capabilities flags | |
251 | #endif | |
252 | ||
253 | extern struct backing_dev_info default_backing_dev_info; | |
5129a469 | 254 | extern struct backing_dev_info noop_backing_dev_info; |
1da177e4 | 255 | |
1da177e4 | 256 | int writeback_in_progress(struct backing_dev_info *bdi); |
1da177e4 LT |
257 | |
258 | static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) | |
259 | { | |
260 | if (bdi->congested_fn) | |
261 | return bdi->congested_fn(bdi->congested_data, bdi_bits); | |
262 | return (bdi->state & bdi_bits); | |
263 | } | |
264 | ||
265 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
266 | { | |
1faa16d2 | 267 | return bdi_congested(bdi, 1 << BDI_sync_congested); |
1da177e4 LT |
268 | } |
269 | ||
270 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
271 | { | |
1faa16d2 | 272 | return bdi_congested(bdi, 1 << BDI_async_congested); |
1da177e4 LT |
273 | } |
274 | ||
275 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
276 | { | |
1faa16d2 JA |
277 | return bdi_congested(bdi, (1 << BDI_sync_congested) | |
278 | (1 << BDI_async_congested)); | |
1da177e4 LT |
279 | } |
280 | ||
373c0a7e TM |
281 | enum { |
282 | BLK_RW_ASYNC = 0, | |
283 | BLK_RW_SYNC = 1, | |
284 | }; | |
285 | ||
8aa7e847 JA |
286 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync); |
287 | void set_bdi_congested(struct backing_dev_info *bdi, int sync); | |
288 | long congestion_wait(int sync, long timeout); | |
0e093d99 | 289 | long wait_iff_congested(struct zone *zone, int sync, long timeout); |
1da177e4 | 290 | |
e4ad08fe MS |
291 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
292 | { | |
293 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
294 | } | |
295 | ||
296 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
297 | { | |
298 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
299 | } | |
1da177e4 | 300 | |
e4ad08fe MS |
301 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
302 | { | |
303 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
304 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
305 | BDI_CAP_NO_WRITEBACK)); | |
306 | } | |
1da177e4 | 307 | |
4f98a2fe RR |
308 | static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi) |
309 | { | |
310 | return bdi->capabilities & BDI_CAP_SWAP_BACKED; | |
311 | } | |
312 | ||
03ba3782 JA |
313 | static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi) |
314 | { | |
315 | return bdi == &default_backing_dev_info; | |
316 | } | |
317 | ||
e4ad08fe MS |
318 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
319 | { | |
320 | return bdi_cap_writeback_dirty(mapping->backing_dev_info); | |
321 | } | |
1da177e4 | 322 | |
e4ad08fe MS |
323 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
324 | { | |
325 | return bdi_cap_account_dirty(mapping->backing_dev_info); | |
326 | } | |
1da177e4 | 327 | |
4f98a2fe RR |
328 | static inline bool mapping_cap_swap_backed(struct address_space *mapping) |
329 | { | |
330 | return bdi_cap_swap_backed(mapping->backing_dev_info); | |
331 | } | |
332 | ||
03ba3782 JA |
333 | static inline int bdi_sched_wait(void *word) |
334 | { | |
335 | schedule(); | |
336 | return 0; | |
337 | } | |
338 | ||
1da177e4 | 339 | #endif /* _LINUX_BACKING_DEV_H */ |