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