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; |
1da177e4 LT |
62 | unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ |
63 | unsigned long state; /* Always use atomic bitops on this */ | |
64 | unsigned int capabilities; /* Device capabilities */ | |
65 | congested_fn *congested_fn; /* Function pointer if device is md/dm */ | |
66 | void *congested_data; /* Pointer to aux data for congested func */ | |
67 | void (*unplug_io_fn)(struct backing_dev_info *, struct page *); | |
68 | void *unplug_io_data; | |
b2e8fb6e | 69 | |
d993831f JA |
70 | char *name; |
71 | ||
b2e8fb6e | 72 | struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; |
04fbfdc1 PZ |
73 | |
74 | struct prop_local_percpu completions; | |
75 | int dirty_exceeded; | |
cf0ca9fe | 76 | |
189d3c4a | 77 | unsigned int min_ratio; |
a42dde04 | 78 | unsigned int max_ratio, max_prop_frac; |
189d3c4a | 79 | |
03ba3782 JA |
80 | struct bdi_writeback wb; /* default writeback info for this bdi */ |
81 | spinlock_t wb_lock; /* protects update side of wb_list */ | |
82 | struct list_head wb_list; /* the flusher threads hanging off this bdi */ | |
83 | unsigned long wb_mask; /* bitmask of registered tasks */ | |
84 | unsigned int wb_cnt; /* number of registered tasks */ | |
76f1418b | 85 | |
03ba3782 JA |
86 | struct list_head work_list; |
87 | ||
88 | struct device *dev; | |
66f3b8e2 | 89 | |
76f1418b MS |
90 | #ifdef CONFIG_DEBUG_FS |
91 | struct dentry *debug_dir; | |
92 | struct dentry *debug_stats; | |
93 | #endif | |
1da177e4 LT |
94 | }; |
95 | ||
b2e8fb6e PZ |
96 | int bdi_init(struct backing_dev_info *bdi); |
97 | void bdi_destroy(struct backing_dev_info *bdi); | |
98 | ||
cf0ca9fe PZ |
99 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
100 | const char *fmt, ...); | |
101 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); | |
102 | void bdi_unregister(struct backing_dev_info *bdi); | |
03ba3782 JA |
103 | void bdi_start_writeback(struct writeback_control *wbc); |
104 | int bdi_writeback_task(struct bdi_writeback *wb); | |
105 | int bdi_has_dirty_io(struct backing_dev_info *bdi); | |
cf0ca9fe | 106 | |
03ba3782 | 107 | extern spinlock_t bdi_lock; |
66f3b8e2 JA |
108 | extern struct list_head bdi_list; |
109 | ||
03ba3782 JA |
110 | static inline int wb_has_dirty_io(struct bdi_writeback *wb) |
111 | { | |
112 | return !list_empty(&wb->b_dirty) || | |
113 | !list_empty(&wb->b_io) || | |
114 | !list_empty(&wb->b_more_io); | |
115 | } | |
116 | ||
b2e8fb6e PZ |
117 | static inline void __add_bdi_stat(struct backing_dev_info *bdi, |
118 | enum bdi_stat_item item, s64 amount) | |
119 | { | |
120 | __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); | |
121 | } | |
122 | ||
123 | static inline void __inc_bdi_stat(struct backing_dev_info *bdi, | |
124 | enum bdi_stat_item item) | |
125 | { | |
126 | __add_bdi_stat(bdi, item, 1); | |
127 | } | |
128 | ||
129 | static inline void inc_bdi_stat(struct backing_dev_info *bdi, | |
130 | enum bdi_stat_item item) | |
131 | { | |
132 | unsigned long flags; | |
133 | ||
134 | local_irq_save(flags); | |
135 | __inc_bdi_stat(bdi, item); | |
136 | local_irq_restore(flags); | |
137 | } | |
138 | ||
139 | static inline void __dec_bdi_stat(struct backing_dev_info *bdi, | |
140 | enum bdi_stat_item item) | |
141 | { | |
142 | __add_bdi_stat(bdi, item, -1); | |
143 | } | |
144 | ||
145 | static inline void dec_bdi_stat(struct backing_dev_info *bdi, | |
146 | enum bdi_stat_item item) | |
147 | { | |
148 | unsigned long flags; | |
149 | ||
150 | local_irq_save(flags); | |
151 | __dec_bdi_stat(bdi, item); | |
152 | local_irq_restore(flags); | |
153 | } | |
154 | ||
155 | static inline s64 bdi_stat(struct backing_dev_info *bdi, | |
156 | enum bdi_stat_item item) | |
157 | { | |
158 | return percpu_counter_read_positive(&bdi->bdi_stat[item]); | |
159 | } | |
160 | ||
161 | static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi, | |
162 | enum bdi_stat_item item) | |
163 | { | |
164 | return percpu_counter_sum_positive(&bdi->bdi_stat[item]); | |
165 | } | |
166 | ||
167 | static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, | |
168 | enum bdi_stat_item item) | |
e0bf68dd | 169 | { |
b2e8fb6e PZ |
170 | s64 sum; |
171 | unsigned long flags; | |
172 | ||
173 | local_irq_save(flags); | |
174 | sum = __bdi_stat_sum(bdi, item); | |
175 | local_irq_restore(flags); | |
176 | ||
177 | return sum; | |
e0bf68dd PZ |
178 | } |
179 | ||
dd5656e5 MS |
180 | extern void bdi_writeout_inc(struct backing_dev_info *bdi); |
181 | ||
b2e8fb6e PZ |
182 | /* |
183 | * maximal error of a stat counter. | |
184 | */ | |
185 | static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) | |
e0bf68dd | 186 | { |
b2e8fb6e PZ |
187 | #ifdef CONFIG_SMP |
188 | return nr_cpu_ids * BDI_STAT_BATCH; | |
189 | #else | |
190 | return 1; | |
191 | #endif | |
e0bf68dd | 192 | } |
1da177e4 | 193 | |
189d3c4a | 194 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 195 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 196 | |
1da177e4 LT |
197 | /* |
198 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
199 | * |
200 | * The first three flags control whether dirty pages will contribute to the | |
201 | * VM's accounting and whether writepages() should be called for dirty pages | |
202 | * (something that would not, for example, be appropriate for ramfs) | |
203 | * | |
204 | * WARNING: these flags are closely related and should not normally be | |
205 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
206 | * three flags into a single convenience macro. | |
207 | * | |
208 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
209 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
210 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
211 | * | |
212 | * These flags let !MMU mmap() govern direct device mapping vs immediate | |
213 | * copying more easily for MAP_PRIVATE, especially for ROM filesystems. | |
214 | * | |
215 | * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE) | |
216 | * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED) | |
217 | * BDI_CAP_READ_MAP: Can be mapped for reading | |
218 | * BDI_CAP_WRITE_MAP: Can be mapped for writing | |
219 | * BDI_CAP_EXEC_MAP: Can be mapped for execution | |
4f98a2fe RR |
220 | * |
221 | * BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed. | |
1da177e4 | 222 | */ |
e4ad08fe MS |
223 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
224 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
225 | #define BDI_CAP_MAP_COPY 0x00000004 | |
226 | #define BDI_CAP_MAP_DIRECT 0x00000008 | |
227 | #define BDI_CAP_READ_MAP 0x00000010 | |
228 | #define BDI_CAP_WRITE_MAP 0x00000020 | |
229 | #define BDI_CAP_EXEC_MAP 0x00000040 | |
230 | #define BDI_CAP_NO_ACCT_WB 0x00000080 | |
4f98a2fe | 231 | #define BDI_CAP_SWAP_BACKED 0x00000100 |
e4ad08fe | 232 | |
1da177e4 LT |
233 | #define BDI_CAP_VMFLAGS \ |
234 | (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) | |
235 | ||
e4ad08fe MS |
236 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
237 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
238 | ||
1da177e4 LT |
239 | #if defined(VM_MAYREAD) && \ |
240 | (BDI_CAP_READ_MAP != VM_MAYREAD || \ | |
241 | BDI_CAP_WRITE_MAP != VM_MAYWRITE || \ | |
242 | BDI_CAP_EXEC_MAP != VM_MAYEXEC) | |
243 | #error please change backing_dev_info::capabilities flags | |
244 | #endif | |
245 | ||
246 | extern struct backing_dev_info default_backing_dev_info; | |
247 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page); | |
248 | ||
1da177e4 | 249 | int writeback_in_progress(struct backing_dev_info *bdi); |
1da177e4 LT |
250 | |
251 | static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) | |
252 | { | |
253 | if (bdi->congested_fn) | |
254 | return bdi->congested_fn(bdi->congested_data, bdi_bits); | |
255 | return (bdi->state & bdi_bits); | |
256 | } | |
257 | ||
258 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
259 | { | |
1faa16d2 | 260 | return bdi_congested(bdi, 1 << BDI_sync_congested); |
1da177e4 LT |
261 | } |
262 | ||
263 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
264 | { | |
1faa16d2 | 265 | return bdi_congested(bdi, 1 << BDI_async_congested); |
1da177e4 LT |
266 | } |
267 | ||
268 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
269 | { | |
1faa16d2 JA |
270 | return bdi_congested(bdi, (1 << BDI_sync_congested) | |
271 | (1 << BDI_async_congested)); | |
1da177e4 LT |
272 | } |
273 | ||
373c0a7e TM |
274 | enum { |
275 | BLK_RW_ASYNC = 0, | |
276 | BLK_RW_SYNC = 1, | |
277 | }; | |
278 | ||
8aa7e847 JA |
279 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync); |
280 | void set_bdi_congested(struct backing_dev_info *bdi, int sync); | |
281 | long congestion_wait(int sync, long timeout); | |
3fcfab16 | 282 | |
1da177e4 | 283 | |
e4ad08fe MS |
284 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
285 | { | |
286 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
287 | } | |
288 | ||
289 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
290 | { | |
291 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
292 | } | |
1da177e4 | 293 | |
e4ad08fe MS |
294 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
295 | { | |
296 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
297 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
298 | BDI_CAP_NO_WRITEBACK)); | |
299 | } | |
1da177e4 | 300 | |
4f98a2fe RR |
301 | static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi) |
302 | { | |
303 | return bdi->capabilities & BDI_CAP_SWAP_BACKED; | |
304 | } | |
305 | ||
03ba3782 JA |
306 | static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi) |
307 | { | |
308 | return bdi == &default_backing_dev_info; | |
309 | } | |
310 | ||
e4ad08fe MS |
311 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
312 | { | |
313 | return bdi_cap_writeback_dirty(mapping->backing_dev_info); | |
314 | } | |
1da177e4 | 315 | |
e4ad08fe MS |
316 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
317 | { | |
318 | return bdi_cap_account_dirty(mapping->backing_dev_info); | |
319 | } | |
1da177e4 | 320 | |
4f98a2fe RR |
321 | static inline bool mapping_cap_swap_backed(struct address_space *mapping) |
322 | { | |
323 | return bdi_cap_swap_backed(mapping->backing_dev_info); | |
324 | } | |
325 | ||
03ba3782 JA |
326 | static inline int bdi_sched_wait(void *word) |
327 | { | |
328 | schedule(); | |
329 | return 0; | |
330 | } | |
331 | ||
1da177e4 | 332 | #endif /* _LINUX_BACKING_DEV_H */ |