Commit | Line | Data |
---|---|---|
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; | |
66f3b8e2 JA |
25 | DEFINE_MUTEX(bdi_lock); |
26 | LIST_HEAD(bdi_list); | |
cf0ca9fe | 27 | |
76f1418b MS |
28 | #ifdef CONFIG_DEBUG_FS |
29 | #include <linux/debugfs.h> | |
30 | #include <linux/seq_file.h> | |
31 | ||
32 | static struct dentry *bdi_debug_root; | |
33 | ||
34 | static void bdi_debug_init(void) | |
35 | { | |
36 | bdi_debug_root = debugfs_create_dir("bdi", NULL); | |
37 | } | |
38 | ||
39 | static int bdi_debug_stats_show(struct seq_file *m, void *v) | |
40 | { | |
41 | struct backing_dev_info *bdi = m->private; | |
364aeb28 DR |
42 | unsigned long background_thresh; |
43 | unsigned long dirty_thresh; | |
44 | unsigned long bdi_thresh; | |
76f1418b MS |
45 | |
46 | get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi); | |
47 | ||
48 | #define K(x) ((x) << (PAGE_SHIFT - 10)) | |
49 | seq_printf(m, | |
50 | "BdiWriteback: %8lu kB\n" | |
51 | "BdiReclaimable: %8lu kB\n" | |
52 | "BdiDirtyThresh: %8lu kB\n" | |
53 | "DirtyThresh: %8lu kB\n" | |
54 | "BackgroundThresh: %8lu kB\n", | |
55 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), | |
56 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), | |
57 | K(bdi_thresh), | |
58 | K(dirty_thresh), | |
59 | K(background_thresh)); | |
60 | #undef K | |
61 | ||
62 | return 0; | |
63 | } | |
64 | ||
65 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) | |
66 | { | |
67 | return single_open(file, bdi_debug_stats_show, inode->i_private); | |
68 | } | |
69 | ||
70 | static const struct file_operations bdi_debug_stats_fops = { | |
71 | .open = bdi_debug_stats_open, | |
72 | .read = seq_read, | |
73 | .llseek = seq_lseek, | |
74 | .release = single_release, | |
75 | }; | |
76 | ||
77 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) | |
78 | { | |
79 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); | |
80 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, | |
81 | bdi, &bdi_debug_stats_fops); | |
82 | } | |
83 | ||
84 | static void bdi_debug_unregister(struct backing_dev_info *bdi) | |
85 | { | |
86 | debugfs_remove(bdi->debug_stats); | |
87 | debugfs_remove(bdi->debug_dir); | |
88 | } | |
89 | #else | |
90 | static inline void bdi_debug_init(void) | |
91 | { | |
92 | } | |
93 | static inline void bdi_debug_register(struct backing_dev_info *bdi, | |
94 | const char *name) | |
95 | { | |
96 | } | |
97 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) | |
98 | { | |
99 | } | |
100 | #endif | |
101 | ||
cf0ca9fe PZ |
102 | static ssize_t read_ahead_kb_store(struct device *dev, |
103 | struct device_attribute *attr, | |
104 | const char *buf, size_t count) | |
105 | { | |
106 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
107 | char *end; | |
108 | unsigned long read_ahead_kb; | |
109 | ssize_t ret = -EINVAL; | |
110 | ||
111 | read_ahead_kb = simple_strtoul(buf, &end, 10); | |
112 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
113 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); | |
114 | ret = count; | |
115 | } | |
116 | return ret; | |
117 | } | |
118 | ||
119 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) | |
120 | ||
121 | #define BDI_SHOW(name, expr) \ | |
122 | static ssize_t name##_show(struct device *dev, \ | |
123 | struct device_attribute *attr, char *page) \ | |
124 | { \ | |
125 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ | |
126 | \ | |
127 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ | |
128 | } | |
129 | ||
130 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) | |
131 | ||
189d3c4a PZ |
132 | static ssize_t min_ratio_store(struct device *dev, |
133 | struct device_attribute *attr, const char *buf, size_t count) | |
134 | { | |
135 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
136 | char *end; | |
137 | unsigned int ratio; | |
138 | ssize_t ret = -EINVAL; | |
139 | ||
140 | ratio = simple_strtoul(buf, &end, 10); | |
141 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
142 | ret = bdi_set_min_ratio(bdi, ratio); | |
143 | if (!ret) | |
144 | ret = count; | |
145 | } | |
146 | return ret; | |
147 | } | |
148 | BDI_SHOW(min_ratio, bdi->min_ratio) | |
149 | ||
a42dde04 PZ |
150 | static ssize_t max_ratio_store(struct device *dev, |
151 | struct device_attribute *attr, const char *buf, size_t count) | |
152 | { | |
153 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
154 | char *end; | |
155 | unsigned int ratio; | |
156 | ssize_t ret = -EINVAL; | |
157 | ||
158 | ratio = simple_strtoul(buf, &end, 10); | |
159 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
160 | ret = bdi_set_max_ratio(bdi, ratio); | |
161 | if (!ret) | |
162 | ret = count; | |
163 | } | |
164 | return ret; | |
165 | } | |
166 | BDI_SHOW(max_ratio, bdi->max_ratio) | |
167 | ||
cf0ca9fe PZ |
168 | #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) |
169 | ||
170 | static struct device_attribute bdi_dev_attrs[] = { | |
171 | __ATTR_RW(read_ahead_kb), | |
189d3c4a | 172 | __ATTR_RW(min_ratio), |
a42dde04 | 173 | __ATTR_RW(max_ratio), |
cf0ca9fe PZ |
174 | __ATTR_NULL, |
175 | }; | |
176 | ||
177 | static __init int bdi_class_init(void) | |
178 | { | |
179 | bdi_class = class_create(THIS_MODULE, "bdi"); | |
180 | bdi_class->dev_attrs = bdi_dev_attrs; | |
76f1418b | 181 | bdi_debug_init(); |
cf0ca9fe PZ |
182 | return 0; |
183 | } | |
76f1418b | 184 | postcore_initcall(bdi_class_init); |
cf0ca9fe | 185 | |
26160158 JA |
186 | static int __init default_bdi_init(void) |
187 | { | |
188 | int err; | |
189 | ||
190 | err = bdi_init(&default_backing_dev_info); | |
191 | if (!err) | |
192 | bdi_register(&default_backing_dev_info, NULL, "default"); | |
193 | ||
194 | return err; | |
195 | } | |
196 | subsys_initcall(default_bdi_init); | |
197 | ||
cf0ca9fe PZ |
198 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
199 | const char *fmt, ...) | |
200 | { | |
cf0ca9fe PZ |
201 | va_list args; |
202 | int ret = 0; | |
203 | struct device *dev; | |
204 | ||
69fc208b | 205 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
f1d0b063 KS |
206 | goto exit; |
207 | ||
cf0ca9fe | 208 | va_start(args, fmt); |
19051c50 | 209 | dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args); |
cf0ca9fe | 210 | va_end(args); |
cf0ca9fe PZ |
211 | if (IS_ERR(dev)) { |
212 | ret = PTR_ERR(dev); | |
213 | goto exit; | |
214 | } | |
215 | ||
66f3b8e2 JA |
216 | mutex_lock(&bdi_lock); |
217 | list_add_tail(&bdi->bdi_list, &bdi_list); | |
218 | mutex_unlock(&bdi_lock); | |
219 | ||
cf0ca9fe | 220 | bdi->dev = dev; |
19051c50 | 221 | bdi_debug_register(bdi, dev_name(dev)); |
cf0ca9fe PZ |
222 | |
223 | exit: | |
cf0ca9fe PZ |
224 | return ret; |
225 | } | |
226 | EXPORT_SYMBOL(bdi_register); | |
227 | ||
228 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) | |
229 | { | |
230 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); | |
231 | } | |
232 | EXPORT_SYMBOL(bdi_register_dev); | |
233 | ||
66f3b8e2 JA |
234 | static void bdi_remove_from_list(struct backing_dev_info *bdi) |
235 | { | |
236 | mutex_lock(&bdi_lock); | |
237 | list_del(&bdi->bdi_list); | |
238 | mutex_unlock(&bdi_lock); | |
239 | } | |
240 | ||
cf0ca9fe PZ |
241 | void bdi_unregister(struct backing_dev_info *bdi) |
242 | { | |
243 | if (bdi->dev) { | |
66f3b8e2 | 244 | bdi_remove_from_list(bdi); |
76f1418b | 245 | bdi_debug_unregister(bdi); |
cf0ca9fe PZ |
246 | device_unregister(bdi->dev); |
247 | bdi->dev = NULL; | |
248 | } | |
249 | } | |
250 | EXPORT_SYMBOL(bdi_unregister); | |
3fcfab16 | 251 | |
b2e8fb6e PZ |
252 | int bdi_init(struct backing_dev_info *bdi) |
253 | { | |
4b01a0b1 | 254 | int i; |
b2e8fb6e PZ |
255 | int err; |
256 | ||
cf0ca9fe PZ |
257 | bdi->dev = NULL; |
258 | ||
189d3c4a | 259 | bdi->min_ratio = 0; |
a42dde04 PZ |
260 | bdi->max_ratio = 100; |
261 | bdi->max_prop_frac = PROP_FRAC_BASE; | |
66f3b8e2 JA |
262 | INIT_LIST_HEAD(&bdi->bdi_list); |
263 | INIT_LIST_HEAD(&bdi->b_io); | |
264 | INIT_LIST_HEAD(&bdi->b_dirty); | |
265 | INIT_LIST_HEAD(&bdi->b_more_io); | |
189d3c4a | 266 | |
b2e8fb6e | 267 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
ea319518 | 268 | err = percpu_counter_init(&bdi->bdi_stat[i], 0); |
04fbfdc1 PZ |
269 | if (err) |
270 | goto err; | |
271 | } | |
272 | ||
273 | bdi->dirty_exceeded = 0; | |
274 | err = prop_local_init_percpu(&bdi->completions); | |
275 | ||
276 | if (err) { | |
277 | err: | |
4b01a0b1 | 278 | while (i--) |
04fbfdc1 | 279 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
66f3b8e2 JA |
280 | |
281 | bdi_remove_from_list(bdi); | |
b2e8fb6e PZ |
282 | } |
283 | ||
284 | return err; | |
285 | } | |
286 | EXPORT_SYMBOL(bdi_init); | |
287 | ||
288 | void bdi_destroy(struct backing_dev_info *bdi) | |
289 | { | |
290 | int i; | |
291 | ||
66f3b8e2 JA |
292 | WARN_ON(!list_empty(&bdi->b_dirty)); |
293 | WARN_ON(!list_empty(&bdi->b_io)); | |
294 | WARN_ON(!list_empty(&bdi->b_more_io)); | |
295 | ||
cf0ca9fe PZ |
296 | bdi_unregister(bdi); |
297 | ||
b2e8fb6e PZ |
298 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
299 | percpu_counter_destroy(&bdi->bdi_stat[i]); | |
04fbfdc1 PZ |
300 | |
301 | prop_local_destroy_percpu(&bdi->completions); | |
b2e8fb6e PZ |
302 | } |
303 | EXPORT_SYMBOL(bdi_destroy); | |
304 | ||
3fcfab16 AM |
305 | static wait_queue_head_t congestion_wqh[2] = { |
306 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), | |
307 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) | |
308 | }; | |
309 | ||
1faa16d2 | 310 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
3fcfab16 AM |
311 | { |
312 | enum bdi_state bit; | |
1faa16d2 | 313 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
3fcfab16 | 314 | |
1faa16d2 | 315 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
3fcfab16 AM |
316 | clear_bit(bit, &bdi->state); |
317 | smp_mb__after_clear_bit(); | |
318 | if (waitqueue_active(wqh)) | |
319 | wake_up(wqh); | |
320 | } | |
321 | EXPORT_SYMBOL(clear_bdi_congested); | |
322 | ||
1faa16d2 | 323 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
3fcfab16 AM |
324 | { |
325 | enum bdi_state bit; | |
326 | ||
1faa16d2 | 327 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
3fcfab16 AM |
328 | set_bit(bit, &bdi->state); |
329 | } | |
330 | EXPORT_SYMBOL(set_bdi_congested); | |
331 | ||
332 | /** | |
333 | * congestion_wait - wait for a backing_dev to become uncongested | |
8aa7e847 | 334 | * @sync: SYNC or ASYNC IO |
3fcfab16 AM |
335 | * @timeout: timeout in jiffies |
336 | * | |
337 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit | |
338 | * write congestion. If no backing_devs are congested then just wait for the | |
339 | * next write to be completed. | |
340 | */ | |
8aa7e847 | 341 | long congestion_wait(int sync, long timeout) |
3fcfab16 AM |
342 | { |
343 | long ret; | |
344 | DEFINE_WAIT(wait); | |
8aa7e847 | 345 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
3fcfab16 AM |
346 | |
347 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
348 | ret = io_schedule_timeout(timeout); | |
349 | finish_wait(wqh, &wait); | |
350 | return ret; | |
351 | } | |
352 | EXPORT_SYMBOL(congestion_wait); | |
04fbfdc1 | 353 |