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 JA |
16 | #include <linux/sched.h> |
17 | #include <linux/writeback.h> | |
1da177e4 LT |
18 | #include <asm/atomic.h> |
19 | ||
3fcfab16 | 20 | struct page; |
cf0ca9fe | 21 | struct device; |
76f1418b | 22 | struct dentry; |
3fcfab16 | 23 | |
1da177e4 LT |
24 | /* |
25 | * Bits in backing_dev_info.state | |
26 | */ | |
27 | enum bdi_state { | |
03ba3782 JA |
28 | BDI_pending, /* On its way to being activated */ |
29 | BDI_wb_alloc, /* Default embedded wb allocated */ | |
1faa16d2 JA |
30 | BDI_async_congested, /* The async (write) queue is getting full */ |
31 | BDI_sync_congested, /* The sync queue is getting full */ | |
500b067c | 32 | BDI_registered, /* bdi_register() was done */ |
1da177e4 LT |
33 | BDI_unused, /* Available bits start here */ |
34 | }; | |
35 | ||
36 | typedef int (congested_fn)(void *, int); | |
37 | ||
b2e8fb6e | 38 | enum bdi_stat_item { |
c9e51e41 | 39 | BDI_RECLAIMABLE, |
69cb51d1 | 40 | BDI_WRITEBACK, |
b2e8fb6e PZ |
41 | NR_BDI_STAT_ITEMS |
42 | }; | |
43 | ||
44 | #define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) | |
45 | ||
03ba3782 JA |
46 | struct bdi_writeback { |
47 | struct list_head list; /* hangs off the bdi */ | |
48 | ||
49 | struct backing_dev_info *bdi; /* our parent bdi */ | |
50 | unsigned int nr; | |
51 | ||
52 | unsigned long last_old_flush; /* last old data flush */ | |
53 | ||
54 | struct task_struct *task; /* writeback task */ | |
55 | struct list_head b_dirty; /* dirty inodes */ | |
56 | struct list_head b_io; /* parked for writeback */ | |
57 | struct list_head b_more_io; /* parked for more writeback */ | |
58 | }; | |
59 | ||
1da177e4 | 60 | struct backing_dev_info { |
66f3b8e2 | 61 | struct list_head bdi_list; |
cfc4ba53 | 62 | struct rcu_head rcu_head; |
1da177e4 LT |
63 | unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ |
64 | unsigned long state; /* Always use atomic bitops on this */ | |
65 | unsigned int capabilities; /* Device capabilities */ | |
66 | congested_fn *congested_fn; /* Function pointer if device is md/dm */ | |
67 | void *congested_data; /* Pointer to aux data for congested func */ | |
68 | void (*unplug_io_fn)(struct backing_dev_info *, struct page *); | |
69 | void *unplug_io_data; | |
b2e8fb6e | 70 | |
d993831f JA |
71 | char *name; |
72 | ||
b2e8fb6e | 73 | struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; |
04fbfdc1 PZ |
74 | |
75 | struct prop_local_percpu completions; | |
76 | int dirty_exceeded; | |
cf0ca9fe | 77 | |
189d3c4a | 78 | unsigned int min_ratio; |
a42dde04 | 79 | unsigned int max_ratio, max_prop_frac; |
189d3c4a | 80 | |
03ba3782 JA |
81 | struct bdi_writeback wb; /* default writeback info for this bdi */ |
82 | spinlock_t wb_lock; /* protects update side of wb_list */ | |
83 | struct list_head wb_list; /* the flusher threads hanging off this bdi */ | |
84 | unsigned long wb_mask; /* bitmask of registered tasks */ | |
85 | unsigned int wb_cnt; /* number of registered tasks */ | |
76f1418b | 86 | |
03ba3782 JA |
87 | struct list_head work_list; |
88 | ||
89 | struct device *dev; | |
66f3b8e2 | 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); |
a72bfd4d JA |
105 | void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, |
106 | long nr_pages); | |
03ba3782 JA |
107 | int bdi_writeback_task(struct bdi_writeback *wb); |
108 | int bdi_has_dirty_io(struct backing_dev_info *bdi); | |
cf0ca9fe | 109 | |
03ba3782 | 110 | extern spinlock_t bdi_lock; |
66f3b8e2 JA |
111 | extern struct list_head bdi_list; |
112 | ||
03ba3782 JA |
113 | static inline int wb_has_dirty_io(struct bdi_writeback *wb) |
114 | { | |
115 | return !list_empty(&wb->b_dirty) || | |
116 | !list_empty(&wb->b_io) || | |
117 | !list_empty(&wb->b_more_io); | |
118 | } | |
119 | ||
b2e8fb6e PZ |
120 | static inline void __add_bdi_stat(struct backing_dev_info *bdi, |
121 | enum bdi_stat_item item, s64 amount) | |
122 | { | |
123 | __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); | |
124 | } | |
125 | ||
126 | static inline void __inc_bdi_stat(struct backing_dev_info *bdi, | |
127 | enum bdi_stat_item item) | |
128 | { | |
129 | __add_bdi_stat(bdi, item, 1); | |
130 | } | |
131 | ||
132 | static inline void inc_bdi_stat(struct backing_dev_info *bdi, | |
133 | enum bdi_stat_item item) | |
134 | { | |
135 | unsigned long flags; | |
136 | ||
137 | local_irq_save(flags); | |
138 | __inc_bdi_stat(bdi, item); | |
139 | local_irq_restore(flags); | |
140 | } | |
141 | ||
142 | static inline void __dec_bdi_stat(struct backing_dev_info *bdi, | |
143 | enum bdi_stat_item item) | |
144 | { | |
145 | __add_bdi_stat(bdi, item, -1); | |
146 | } | |
147 | ||
148 | static inline void dec_bdi_stat(struct backing_dev_info *bdi, | |
149 | enum bdi_stat_item item) | |
150 | { | |
151 | unsigned long flags; | |
152 | ||
153 | local_irq_save(flags); | |
154 | __dec_bdi_stat(bdi, item); | |
155 | local_irq_restore(flags); | |
156 | } | |
157 | ||
158 | static inline s64 bdi_stat(struct backing_dev_info *bdi, | |
159 | enum bdi_stat_item item) | |
160 | { | |
161 | return percpu_counter_read_positive(&bdi->bdi_stat[item]); | |
162 | } | |
163 | ||
164 | static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi, | |
165 | enum bdi_stat_item item) | |
166 | { | |
167 | return percpu_counter_sum_positive(&bdi->bdi_stat[item]); | |
168 | } | |
169 | ||
170 | static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, | |
171 | enum bdi_stat_item item) | |
e0bf68dd | 172 | { |
b2e8fb6e PZ |
173 | s64 sum; |
174 | unsigned long flags; | |
175 | ||
176 | local_irq_save(flags); | |
177 | sum = __bdi_stat_sum(bdi, item); | |
178 | local_irq_restore(flags); | |
179 | ||
180 | return sum; | |
e0bf68dd PZ |
181 | } |
182 | ||
dd5656e5 MS |
183 | extern void bdi_writeout_inc(struct backing_dev_info *bdi); |
184 | ||
b2e8fb6e PZ |
185 | /* |
186 | * maximal error of a stat counter. | |
187 | */ | |
188 | static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) | |
e0bf68dd | 189 | { |
b2e8fb6e PZ |
190 | #ifdef CONFIG_SMP |
191 | return nr_cpu_ids * BDI_STAT_BATCH; | |
192 | #else | |
193 | return 1; | |
194 | #endif | |
e0bf68dd | 195 | } |
1da177e4 | 196 | |
189d3c4a | 197 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 198 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 199 | |
1da177e4 LT |
200 | /* |
201 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
202 | * |
203 | * The first three flags control whether dirty pages will contribute to the | |
204 | * VM's accounting and whether writepages() should be called for dirty pages | |
205 | * (something that would not, for example, be appropriate for ramfs) | |
206 | * | |
207 | * WARNING: these flags are closely related and should not normally be | |
208 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
209 | * three flags into a single convenience macro. | |
210 | * | |
211 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
212 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
213 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
214 | * | |
215 | * These flags let !MMU mmap() govern direct device mapping vs immediate | |
216 | * copying more easily for MAP_PRIVATE, especially for ROM filesystems. | |
217 | * | |
218 | * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE) | |
219 | * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED) | |
220 | * BDI_CAP_READ_MAP: Can be mapped for reading | |
221 | * BDI_CAP_WRITE_MAP: Can be mapped for writing | |
222 | * BDI_CAP_EXEC_MAP: Can be mapped for execution | |
4f98a2fe RR |
223 | * |
224 | * BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed. | |
1da177e4 | 225 | */ |
e4ad08fe MS |
226 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
227 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
228 | #define BDI_CAP_MAP_COPY 0x00000004 | |
229 | #define BDI_CAP_MAP_DIRECT 0x00000008 | |
230 | #define BDI_CAP_READ_MAP 0x00000010 | |
231 | #define BDI_CAP_WRITE_MAP 0x00000020 | |
232 | #define BDI_CAP_EXEC_MAP 0x00000040 | |
233 | #define BDI_CAP_NO_ACCT_WB 0x00000080 | |
4f98a2fe | 234 | #define BDI_CAP_SWAP_BACKED 0x00000100 |
e4ad08fe | 235 | |
1da177e4 LT |
236 | #define BDI_CAP_VMFLAGS \ |
237 | (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) | |
238 | ||
e4ad08fe MS |
239 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
240 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
241 | ||
1da177e4 LT |
242 | #if defined(VM_MAYREAD) && \ |
243 | (BDI_CAP_READ_MAP != VM_MAYREAD || \ | |
244 | BDI_CAP_WRITE_MAP != VM_MAYWRITE || \ | |
245 | BDI_CAP_EXEC_MAP != VM_MAYEXEC) | |
246 | #error please change backing_dev_info::capabilities flags | |
247 | #endif | |
248 | ||
249 | extern struct backing_dev_info default_backing_dev_info; | |
5129a469 | 250 | extern struct backing_dev_info noop_backing_dev_info; |
1da177e4 LT |
251 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page); |
252 | ||
1da177e4 | 253 | int writeback_in_progress(struct backing_dev_info *bdi); |
1da177e4 LT |
254 | |
255 | static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) | |
256 | { | |
257 | if (bdi->congested_fn) | |
258 | return bdi->congested_fn(bdi->congested_data, bdi_bits); | |
259 | return (bdi->state & bdi_bits); | |
260 | } | |
261 | ||
262 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
263 | { | |
1faa16d2 | 264 | return bdi_congested(bdi, 1 << BDI_sync_congested); |
1da177e4 LT |
265 | } |
266 | ||
267 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
268 | { | |
1faa16d2 | 269 | return bdi_congested(bdi, 1 << BDI_async_congested); |
1da177e4 LT |
270 | } |
271 | ||
272 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
273 | { | |
1faa16d2 JA |
274 | return bdi_congested(bdi, (1 << BDI_sync_congested) | |
275 | (1 << BDI_async_congested)); | |
1da177e4 LT |
276 | } |
277 | ||
373c0a7e TM |
278 | enum { |
279 | BLK_RW_ASYNC = 0, | |
280 | BLK_RW_SYNC = 1, | |
281 | }; | |
282 | ||
8aa7e847 JA |
283 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync); |
284 | void set_bdi_congested(struct backing_dev_info *bdi, int sync); | |
285 | long congestion_wait(int sync, long timeout); | |
3fcfab16 | 286 | |
1da177e4 | 287 | |
e4ad08fe MS |
288 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
289 | { | |
290 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
291 | } | |
292 | ||
293 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
294 | { | |
295 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
296 | } | |
1da177e4 | 297 | |
e4ad08fe MS |
298 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
299 | { | |
300 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
301 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
302 | BDI_CAP_NO_WRITEBACK)); | |
303 | } | |
1da177e4 | 304 | |
4f98a2fe RR |
305 | static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi) |
306 | { | |
307 | return bdi->capabilities & BDI_CAP_SWAP_BACKED; | |
308 | } | |
309 | ||
03ba3782 JA |
310 | static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi) |
311 | { | |
312 | return bdi == &default_backing_dev_info; | |
313 | } | |
314 | ||
e4ad08fe MS |
315 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
316 | { | |
317 | return bdi_cap_writeback_dirty(mapping->backing_dev_info); | |
318 | } | |
1da177e4 | 319 | |
e4ad08fe MS |
320 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
321 | { | |
322 | return bdi_cap_account_dirty(mapping->backing_dev_info); | |
323 | } | |
1da177e4 | 324 | |
4f98a2fe RR |
325 | static inline bool mapping_cap_swap_backed(struct address_space *mapping) |
326 | { | |
327 | return bdi_cap_swap_backed(mapping->backing_dev_info); | |
328 | } | |
329 | ||
03ba3782 JA |
330 | static inline int bdi_sched_wait(void *word) |
331 | { | |
332 | schedule(); | |
333 | return 0; | |
334 | } | |
335 | ||
b9d128f1 JA |
336 | static inline void blk_run_backing_dev(struct backing_dev_info *bdi, |
337 | struct page *page) | |
338 | { | |
339 | if (bdi && bdi->unplug_io_fn) | |
340 | bdi->unplug_io_fn(bdi, page); | |
341 | } | |
342 | ||
343 | static inline void blk_run_address_space(struct address_space *mapping) | |
344 | { | |
345 | if (mapping) | |
346 | blk_run_backing_dev(mapping->backing_dev_info, NULL); | |
347 | } | |
348 | ||
1da177e4 | 349 | #endif /* _LINUX_BACKING_DEV_H */ |