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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> |
1da177e4 LT |
16 | #include <asm/atomic.h> |
17 | ||
3fcfab16 | 18 | struct page; |
cf0ca9fe | 19 | struct device; |
76f1418b | 20 | struct dentry; |
3fcfab16 | 21 | |
1da177e4 LT |
22 | /* |
23 | * Bits in backing_dev_info.state | |
24 | */ | |
25 | enum bdi_state { | |
26 | BDI_pdflush, /* A pdflush thread is working this device */ | |
27 | BDI_write_congested, /* The write queue is getting full */ | |
28 | BDI_read_congested, /* The read queue is getting full */ | |
29 | BDI_unused, /* Available bits start here */ | |
30 | }; | |
31 | ||
32 | typedef int (congested_fn)(void *, int); | |
33 | ||
b2e8fb6e | 34 | enum bdi_stat_item { |
c9e51e41 | 35 | BDI_RECLAIMABLE, |
69cb51d1 | 36 | BDI_WRITEBACK, |
b2e8fb6e PZ |
37 | NR_BDI_STAT_ITEMS |
38 | }; | |
39 | ||
40 | #define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) | |
41 | ||
1da177e4 LT |
42 | struct backing_dev_info { |
43 | unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ | |
44 | unsigned long state; /* Always use atomic bitops on this */ | |
45 | unsigned int capabilities; /* Device capabilities */ | |
46 | congested_fn *congested_fn; /* Function pointer if device is md/dm */ | |
47 | void *congested_data; /* Pointer to aux data for congested func */ | |
48 | void (*unplug_io_fn)(struct backing_dev_info *, struct page *); | |
49 | void *unplug_io_data; | |
b2e8fb6e PZ |
50 | |
51 | struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; | |
04fbfdc1 PZ |
52 | |
53 | struct prop_local_percpu completions; | |
54 | int dirty_exceeded; | |
cf0ca9fe | 55 | |
189d3c4a | 56 | unsigned int min_ratio; |
a42dde04 | 57 | unsigned int max_ratio, max_prop_frac; |
189d3c4a | 58 | |
cf0ca9fe | 59 | struct device *dev; |
76f1418b MS |
60 | |
61 | #ifdef CONFIG_DEBUG_FS | |
62 | struct dentry *debug_dir; | |
63 | struct dentry *debug_stats; | |
64 | #endif | |
1da177e4 LT |
65 | }; |
66 | ||
b2e8fb6e PZ |
67 | int bdi_init(struct backing_dev_info *bdi); |
68 | void bdi_destroy(struct backing_dev_info *bdi); | |
69 | ||
cf0ca9fe PZ |
70 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
71 | const char *fmt, ...); | |
72 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); | |
73 | void bdi_unregister(struct backing_dev_info *bdi); | |
74 | ||
b2e8fb6e PZ |
75 | static inline void __add_bdi_stat(struct backing_dev_info *bdi, |
76 | enum bdi_stat_item item, s64 amount) | |
77 | { | |
78 | __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); | |
79 | } | |
80 | ||
81 | static inline void __inc_bdi_stat(struct backing_dev_info *bdi, | |
82 | enum bdi_stat_item item) | |
83 | { | |
84 | __add_bdi_stat(bdi, item, 1); | |
85 | } | |
86 | ||
87 | static inline void inc_bdi_stat(struct backing_dev_info *bdi, | |
88 | enum bdi_stat_item item) | |
89 | { | |
90 | unsigned long flags; | |
91 | ||
92 | local_irq_save(flags); | |
93 | __inc_bdi_stat(bdi, item); | |
94 | local_irq_restore(flags); | |
95 | } | |
96 | ||
97 | static inline void __dec_bdi_stat(struct backing_dev_info *bdi, | |
98 | enum bdi_stat_item item) | |
99 | { | |
100 | __add_bdi_stat(bdi, item, -1); | |
101 | } | |
102 | ||
103 | static inline void dec_bdi_stat(struct backing_dev_info *bdi, | |
104 | enum bdi_stat_item item) | |
105 | { | |
106 | unsigned long flags; | |
107 | ||
108 | local_irq_save(flags); | |
109 | __dec_bdi_stat(bdi, item); | |
110 | local_irq_restore(flags); | |
111 | } | |
112 | ||
113 | static inline s64 bdi_stat(struct backing_dev_info *bdi, | |
114 | enum bdi_stat_item item) | |
115 | { | |
116 | return percpu_counter_read_positive(&bdi->bdi_stat[item]); | |
117 | } | |
118 | ||
119 | static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi, | |
120 | enum bdi_stat_item item) | |
121 | { | |
122 | return percpu_counter_sum_positive(&bdi->bdi_stat[item]); | |
123 | } | |
124 | ||
125 | static inline s64 bdi_stat_sum(struct backing_dev_info *bdi, | |
126 | enum bdi_stat_item item) | |
e0bf68dd | 127 | { |
b2e8fb6e PZ |
128 | s64 sum; |
129 | unsigned long flags; | |
130 | ||
131 | local_irq_save(flags); | |
132 | sum = __bdi_stat_sum(bdi, item); | |
133 | local_irq_restore(flags); | |
134 | ||
135 | return sum; | |
e0bf68dd PZ |
136 | } |
137 | ||
b2e8fb6e PZ |
138 | /* |
139 | * maximal error of a stat counter. | |
140 | */ | |
141 | static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi) | |
e0bf68dd | 142 | { |
b2e8fb6e PZ |
143 | #ifdef CONFIG_SMP |
144 | return nr_cpu_ids * BDI_STAT_BATCH; | |
145 | #else | |
146 | return 1; | |
147 | #endif | |
e0bf68dd | 148 | } |
1da177e4 | 149 | |
189d3c4a | 150 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 151 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 152 | |
1da177e4 LT |
153 | /* |
154 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
155 | * |
156 | * The first three flags control whether dirty pages will contribute to the | |
157 | * VM's accounting and whether writepages() should be called for dirty pages | |
158 | * (something that would not, for example, be appropriate for ramfs) | |
159 | * | |
160 | * WARNING: these flags are closely related and should not normally be | |
161 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
162 | * three flags into a single convenience macro. | |
163 | * | |
164 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
165 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
166 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
167 | * | |
168 | * These flags let !MMU mmap() govern direct device mapping vs immediate | |
169 | * copying more easily for MAP_PRIVATE, especially for ROM filesystems. | |
170 | * | |
171 | * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE) | |
172 | * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED) | |
173 | * BDI_CAP_READ_MAP: Can be mapped for reading | |
174 | * BDI_CAP_WRITE_MAP: Can be mapped for writing | |
175 | * BDI_CAP_EXEC_MAP: Can be mapped for execution | |
1da177e4 | 176 | */ |
e4ad08fe MS |
177 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
178 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
179 | #define BDI_CAP_MAP_COPY 0x00000004 | |
180 | #define BDI_CAP_MAP_DIRECT 0x00000008 | |
181 | #define BDI_CAP_READ_MAP 0x00000010 | |
182 | #define BDI_CAP_WRITE_MAP 0x00000020 | |
183 | #define BDI_CAP_EXEC_MAP 0x00000040 | |
184 | #define BDI_CAP_NO_ACCT_WB 0x00000080 | |
185 | ||
1da177e4 LT |
186 | #define BDI_CAP_VMFLAGS \ |
187 | (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) | |
188 | ||
e4ad08fe MS |
189 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
190 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
191 | ||
1da177e4 LT |
192 | #if defined(VM_MAYREAD) && \ |
193 | (BDI_CAP_READ_MAP != VM_MAYREAD || \ | |
194 | BDI_CAP_WRITE_MAP != VM_MAYWRITE || \ | |
195 | BDI_CAP_EXEC_MAP != VM_MAYEXEC) | |
196 | #error please change backing_dev_info::capabilities flags | |
197 | #endif | |
198 | ||
199 | extern struct backing_dev_info default_backing_dev_info; | |
200 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page); | |
201 | ||
1da177e4 | 202 | int writeback_in_progress(struct backing_dev_info *bdi); |
1da177e4 LT |
203 | |
204 | static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) | |
205 | { | |
206 | if (bdi->congested_fn) | |
207 | return bdi->congested_fn(bdi->congested_data, bdi_bits); | |
208 | return (bdi->state & bdi_bits); | |
209 | } | |
210 | ||
211 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
212 | { | |
213 | return bdi_congested(bdi, 1 << BDI_read_congested); | |
214 | } | |
215 | ||
216 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
217 | { | |
218 | return bdi_congested(bdi, 1 << BDI_write_congested); | |
219 | } | |
220 | ||
221 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
222 | { | |
223 | return bdi_congested(bdi, (1 << BDI_read_congested)| | |
224 | (1 << BDI_write_congested)); | |
225 | } | |
226 | ||
3fcfab16 AM |
227 | void clear_bdi_congested(struct backing_dev_info *bdi, int rw); |
228 | void set_bdi_congested(struct backing_dev_info *bdi, int rw); | |
229 | long congestion_wait(int rw, long timeout); | |
3fcfab16 | 230 | |
1da177e4 | 231 | |
e4ad08fe MS |
232 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
233 | { | |
234 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
235 | } | |
236 | ||
237 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
238 | { | |
239 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
240 | } | |
1da177e4 | 241 | |
e4ad08fe MS |
242 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
243 | { | |
244 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
245 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
246 | BDI_CAP_NO_WRITEBACK)); | |
247 | } | |
1da177e4 | 248 | |
e4ad08fe MS |
249 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
250 | { | |
251 | return bdi_cap_writeback_dirty(mapping->backing_dev_info); | |
252 | } | |
1da177e4 | 253 | |
e4ad08fe MS |
254 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
255 | { | |
256 | return bdi_cap_account_dirty(mapping->backing_dev_info); | |
257 | } | |
1da177e4 LT |
258 | |
259 | #endif /* _LINUX_BACKING_DEV_H */ |