Commit | Line | Data |
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3fcfab16 AM |
1 | |
2 | #include <linux/wait.h> | |
3 | #include <linux/backing-dev.h> | |
4 | #include <linux/fs.h> | |
26160158 | 5 | #include <linux/pagemap.h> |
3fcfab16 AM |
6 | #include <linux/sched.h> |
7 | #include <linux/module.h> | |
cf0ca9fe PZ |
8 | #include <linux/writeback.h> |
9 | #include <linux/device.h> | |
10 | ||
26160158 JA |
11 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
12 | { | |
13 | } | |
14 | EXPORT_SYMBOL(default_unplug_io_fn); | |
15 | ||
16 | struct backing_dev_info default_backing_dev_info = { | |
17 | .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE, | |
18 | .state = 0, | |
19 | .capabilities = BDI_CAP_MAP_COPY, | |
20 | .unplug_io_fn = default_unplug_io_fn, | |
21 | }; | |
22 | EXPORT_SYMBOL_GPL(default_backing_dev_info); | |
cf0ca9fe PZ |
23 | |
24 | static struct class *bdi_class; | |
25 | ||
76f1418b MS |
26 | #ifdef CONFIG_DEBUG_FS |
27 | #include <linux/debugfs.h> | |
28 | #include <linux/seq_file.h> | |
29 | ||
30 | static struct dentry *bdi_debug_root; | |
31 | ||
32 | static void bdi_debug_init(void) | |
33 | { | |
34 | bdi_debug_root = debugfs_create_dir("bdi", NULL); | |
35 | } | |
36 | ||
37 | static int bdi_debug_stats_show(struct seq_file *m, void *v) | |
38 | { | |
39 | struct backing_dev_info *bdi = m->private; | |
364aeb28 DR |
40 | unsigned long background_thresh; |
41 | unsigned long dirty_thresh; | |
42 | unsigned long bdi_thresh; | |
76f1418b MS |
43 | |
44 | get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi); | |
45 | ||
46 | #define K(x) ((x) << (PAGE_SHIFT - 10)) | |
47 | seq_printf(m, | |
48 | "BdiWriteback: %8lu kB\n" | |
49 | "BdiReclaimable: %8lu kB\n" | |
50 | "BdiDirtyThresh: %8lu kB\n" | |
51 | "DirtyThresh: %8lu kB\n" | |
52 | "BackgroundThresh: %8lu kB\n", | |
53 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), | |
54 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), | |
55 | K(bdi_thresh), | |
56 | K(dirty_thresh), | |
57 | K(background_thresh)); | |
58 | #undef K | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
63 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) | |
64 | { | |
65 | return single_open(file, bdi_debug_stats_show, inode->i_private); | |
66 | } | |
67 | ||
68 | static const struct file_operations bdi_debug_stats_fops = { | |
69 | .open = bdi_debug_stats_open, | |
70 | .read = seq_read, | |
71 | .llseek = seq_lseek, | |
72 | .release = single_release, | |
73 | }; | |
74 | ||
75 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) | |
76 | { | |
77 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); | |
78 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, | |
79 | bdi, &bdi_debug_stats_fops); | |
80 | } | |
81 | ||
82 | static void bdi_debug_unregister(struct backing_dev_info *bdi) | |
83 | { | |
84 | debugfs_remove(bdi->debug_stats); | |
85 | debugfs_remove(bdi->debug_dir); | |
86 | } | |
87 | #else | |
88 | static inline void bdi_debug_init(void) | |
89 | { | |
90 | } | |
91 | static inline void bdi_debug_register(struct backing_dev_info *bdi, | |
92 | const char *name) | |
93 | { | |
94 | } | |
95 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) | |
96 | { | |
97 | } | |
98 | #endif | |
99 | ||
cf0ca9fe PZ |
100 | static ssize_t read_ahead_kb_store(struct device *dev, |
101 | struct device_attribute *attr, | |
102 | const char *buf, size_t count) | |
103 | { | |
104 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
105 | char *end; | |
106 | unsigned long read_ahead_kb; | |
107 | ssize_t ret = -EINVAL; | |
108 | ||
109 | read_ahead_kb = simple_strtoul(buf, &end, 10); | |
110 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
111 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); | |
112 | ret = count; | |
113 | } | |
114 | return ret; | |
115 | } | |
116 | ||
117 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) | |
118 | ||
119 | #define BDI_SHOW(name, expr) \ | |
120 | static ssize_t name##_show(struct device *dev, \ | |
121 | struct device_attribute *attr, char *page) \ | |
122 | { \ | |
123 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ | |
124 | \ | |
125 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ | |
126 | } | |
127 | ||
128 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) | |
129 | ||
189d3c4a PZ |
130 | static ssize_t min_ratio_store(struct device *dev, |
131 | struct device_attribute *attr, const char *buf, size_t count) | |
132 | { | |
133 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
134 | char *end; | |
135 | unsigned int ratio; | |
136 | ssize_t ret = -EINVAL; | |
137 | ||
138 | ratio = simple_strtoul(buf, &end, 10); | |
139 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
140 | ret = bdi_set_min_ratio(bdi, ratio); | |
141 | if (!ret) | |
142 | ret = count; | |
143 | } | |
144 | return ret; | |
145 | } | |
146 | BDI_SHOW(min_ratio, bdi->min_ratio) | |
147 | ||
a42dde04 PZ |
148 | static ssize_t max_ratio_store(struct device *dev, |
149 | struct device_attribute *attr, const char *buf, size_t count) | |
150 | { | |
151 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
152 | char *end; | |
153 | unsigned int ratio; | |
154 | ssize_t ret = -EINVAL; | |
155 | ||
156 | ratio = simple_strtoul(buf, &end, 10); | |
157 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
158 | ret = bdi_set_max_ratio(bdi, ratio); | |
159 | if (!ret) | |
160 | ret = count; | |
161 | } | |
162 | return ret; | |
163 | } | |
164 | BDI_SHOW(max_ratio, bdi->max_ratio) | |
165 | ||
cf0ca9fe PZ |
166 | #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) |
167 | ||
168 | static struct device_attribute bdi_dev_attrs[] = { | |
169 | __ATTR_RW(read_ahead_kb), | |
189d3c4a | 170 | __ATTR_RW(min_ratio), |
a42dde04 | 171 | __ATTR_RW(max_ratio), |
cf0ca9fe PZ |
172 | __ATTR_NULL, |
173 | }; | |
174 | ||
175 | static __init int bdi_class_init(void) | |
176 | { | |
177 | bdi_class = class_create(THIS_MODULE, "bdi"); | |
178 | bdi_class->dev_attrs = bdi_dev_attrs; | |
76f1418b | 179 | bdi_debug_init(); |
cf0ca9fe PZ |
180 | return 0; |
181 | } | |
76f1418b | 182 | postcore_initcall(bdi_class_init); |
cf0ca9fe | 183 | |
26160158 JA |
184 | static int __init default_bdi_init(void) |
185 | { | |
186 | int err; | |
187 | ||
188 | err = bdi_init(&default_backing_dev_info); | |
189 | if (!err) | |
190 | bdi_register(&default_backing_dev_info, NULL, "default"); | |
191 | ||
192 | return err; | |
193 | } | |
194 | subsys_initcall(default_bdi_init); | |
195 | ||
cf0ca9fe PZ |
196 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
197 | const char *fmt, ...) | |
198 | { | |
cf0ca9fe PZ |
199 | va_list args; |
200 | int ret = 0; | |
201 | struct device *dev; | |
202 | ||
69fc208b | 203 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
f1d0b063 KS |
204 | goto exit; |
205 | ||
cf0ca9fe | 206 | va_start(args, fmt); |
19051c50 | 207 | dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args); |
cf0ca9fe | 208 | va_end(args); |
cf0ca9fe PZ |
209 | if (IS_ERR(dev)) { |
210 | ret = PTR_ERR(dev); | |
211 | goto exit; | |
212 | } | |
213 | ||
214 | bdi->dev = dev; | |
19051c50 | 215 | bdi_debug_register(bdi, dev_name(dev)); |
cf0ca9fe PZ |
216 | |
217 | exit: | |
cf0ca9fe PZ |
218 | return ret; |
219 | } | |
220 | EXPORT_SYMBOL(bdi_register); | |
221 | ||
222 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) | |
223 | { | |
224 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); | |
225 | } | |
226 | EXPORT_SYMBOL(bdi_register_dev); | |
227 | ||
228 | void bdi_unregister(struct backing_dev_info *bdi) | |
229 | { | |
230 | if (bdi->dev) { | |
76f1418b | 231 | bdi_debug_unregister(bdi); |
cf0ca9fe PZ |
232 | device_unregister(bdi->dev); |
233 | bdi->dev = NULL; | |
234 | } | |
235 | } | |
236 | EXPORT_SYMBOL(bdi_unregister); | |
3fcfab16 | 237 | |
b2e8fb6e PZ |
238 | int bdi_init(struct backing_dev_info *bdi) |
239 | { | |
4b01a0b1 | 240 | int i; |
b2e8fb6e PZ |
241 | int err; |
242 | ||
cf0ca9fe PZ |
243 | bdi->dev = NULL; |
244 | ||
189d3c4a | 245 | bdi->min_ratio = 0; |
a42dde04 PZ |
246 | bdi->max_ratio = 100; |
247 | bdi->max_prop_frac = PROP_FRAC_BASE; | |
189d3c4a | 248 | |
b2e8fb6e | 249 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
ea319518 | 250 | err = percpu_counter_init(&bdi->bdi_stat[i], 0); |
04fbfdc1 PZ |
251 | if (err) |
252 | goto err; | |
253 | } | |
254 | ||
255 | bdi->dirty_exceeded = 0; | |
256 | err = prop_local_init_percpu(&bdi->completions); | |
257 | ||
258 | if (err) { | |
259 | err: | |
4b01a0b1 | 260 | while (i--) |
04fbfdc1 | 261 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
b2e8fb6e PZ |
262 | } |
263 | ||
264 | return err; | |
265 | } | |
266 | EXPORT_SYMBOL(bdi_init); | |
267 | ||
268 | void bdi_destroy(struct backing_dev_info *bdi) | |
269 | { | |
270 | int i; | |
271 | ||
cf0ca9fe PZ |
272 | bdi_unregister(bdi); |
273 | ||
b2e8fb6e PZ |
274 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
275 | percpu_counter_destroy(&bdi->bdi_stat[i]); | |
04fbfdc1 PZ |
276 | |
277 | prop_local_destroy_percpu(&bdi->completions); | |
b2e8fb6e PZ |
278 | } |
279 | EXPORT_SYMBOL(bdi_destroy); | |
280 | ||
3fcfab16 AM |
281 | static wait_queue_head_t congestion_wqh[2] = { |
282 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), | |
283 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) | |
284 | }; | |
285 | ||
286 | ||
1faa16d2 | 287 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
3fcfab16 AM |
288 | { |
289 | enum bdi_state bit; | |
1faa16d2 | 290 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
3fcfab16 | 291 | |
1faa16d2 | 292 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
3fcfab16 AM |
293 | clear_bit(bit, &bdi->state); |
294 | smp_mb__after_clear_bit(); | |
295 | if (waitqueue_active(wqh)) | |
296 | wake_up(wqh); | |
297 | } | |
298 | EXPORT_SYMBOL(clear_bdi_congested); | |
299 | ||
1faa16d2 | 300 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
3fcfab16 AM |
301 | { |
302 | enum bdi_state bit; | |
303 | ||
1faa16d2 | 304 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
3fcfab16 AM |
305 | set_bit(bit, &bdi->state); |
306 | } | |
307 | EXPORT_SYMBOL(set_bdi_congested); | |
308 | ||
309 | /** | |
310 | * congestion_wait - wait for a backing_dev to become uncongested | |
311 | * @rw: READ or WRITE | |
312 | * @timeout: timeout in jiffies | |
313 | * | |
314 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit | |
315 | * write congestion. If no backing_devs are congested then just wait for the | |
316 | * next write to be completed. | |
317 | */ | |
318 | long congestion_wait(int rw, long timeout) | |
319 | { | |
320 | long ret; | |
321 | DEFINE_WAIT(wait); | |
322 | wait_queue_head_t *wqh = &congestion_wqh[rw]; | |
323 | ||
324 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
325 | ret = io_schedule_timeout(timeout); | |
326 | finish_wait(wqh, &wait); | |
327 | return ret; | |
328 | } | |
329 | EXPORT_SYMBOL(congestion_wait); | |
04fbfdc1 | 330 |