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3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
1
2 #include <linux/wait.h>
3 #include <linux/backing-dev.h>
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
4 #include <linux/kthread.h>
5 #include <linux/freezer.h>
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
6 #include <linux/fs.h>
26160158 » Jens Axboe
2009-03-17 Move the default_backing_dev_info out of readahead.c and into backing…
7 #include <linux/pagemap.h>
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
8 #include <linux/mm.h>
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
9 #include <linux/sched.h>
10 #include <linux/module.h>
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
11 #include <linux/writeback.h>
12 #include <linux/device.h>
455b2864 » dchinner
2010-07-07 writeback: Initial tracing support
13 #include <trace/events/writeback.h>
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
14
c3c53206 » Jens Axboe
2010-04-22 bdi: add helper function for doing init and register of a bdi for a f…
15 static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
16
26160158 » Jens Axboe
2009-03-17 Move the default_backing_dev_info out of readahead.c and into backing…
17 void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
18 {
19 }
20 EXPORT_SYMBOL(default_unplug_io_fn);
21
22 struct backing_dev_info default_backing_dev_info = {
d993831f » Jens Axboe
2009-06-12 writeback: add name to backing_dev_info
23 .name = "default",
26160158 » Jens Axboe
2009-03-17 Move the default_backing_dev_info out of readahead.c and into backing…
24 .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE,
25 .state = 0,
26 .capabilities = BDI_CAP_MAP_COPY,
27 .unplug_io_fn = default_unplug_io_fn,
28 };
29 EXPORT_SYMBOL_GPL(default_backing_dev_info);
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
30
5129a469 » Jörn Engel
2010-04-25 Catch filesystems lacking s_bdi
31 struct backing_dev_info noop_backing_dev_info = {
32 .name = "noop",
33 };
34 EXPORT_SYMBOL_GPL(noop_backing_dev_info);
35
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
36 static struct class *bdi_class;
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
37
38 /*
39 * bdi_lock protects updates to bdi_list and bdi_pending_list, as well as
40 * reader side protection for bdi_pending_list. bdi_list has RCU reader side
41 * locking.
42 */
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
43 DEFINE_SPINLOCK(bdi_lock);
66f3b8e2 » Jens Axboe
2009-09-02 writeback: move dirty inodes from super_block to backing_dev_info
44 LIST_HEAD(bdi_list);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
45 LIST_HEAD(bdi_pending_list);
46
47 static struct task_struct *sync_supers_tsk;
48 static struct timer_list sync_supers_timer;
49
50 static int bdi_sync_supers(void *);
51 static void sync_supers_timer_fn(unsigned long);
52
53 static void bdi_add_default_flusher_task(struct backing_dev_info *bdi);
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
54
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
55 #ifdef CONFIG_DEBUG_FS
56 #include <linux/debugfs.h>
57 #include <linux/seq_file.h>
58
59 static struct dentry *bdi_debug_root;
60
61 static void bdi_debug_init(void)
62 {
63 bdi_debug_root = debugfs_create_dir("bdi", NULL);
64 }
65
66 static int bdi_debug_stats_show(struct seq_file *m, void *v)
67 {
68 struct backing_dev_info *bdi = m->private;
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
69 struct bdi_writeback *wb = &bdi->wb;
364aeb28 » David Rientjes
2009-01-06 mm: change dirty limit type specifiers to unsigned long
70 unsigned long background_thresh;
71 unsigned long dirty_thresh;
72 unsigned long bdi_thresh;
f09b00d3 » Jens Axboe
2009-05-25 writeback: add some debug inode list counters to bdi stats
73 unsigned long nr_dirty, nr_io, nr_more_io, nr_wb;
74 struct inode *inode;
75
76 nr_wb = nr_dirty = nr_io = nr_more_io = 0;
77 spin_lock(&inode_lock);
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
78 list_for_each_entry(inode, &wb->b_dirty, i_list)
79 nr_dirty++;
80 list_for_each_entry(inode, &wb->b_io, i_list)
81 nr_io++;
82 list_for_each_entry(inode, &wb->b_more_io, i_list)
83 nr_more_io++;
f09b00d3 » Jens Axboe
2009-05-25 writeback: add some debug inode list counters to bdi stats
84 spin_unlock(&inode_lock);
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
85
86 get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi);
87
88 #define K(x) ((x) << (PAGE_SHIFT - 10))
89 seq_printf(m,
90 "BdiWriteback: %8lu kB\n"
91 "BdiReclaimable: %8lu kB\n"
92 "BdiDirtyThresh: %8lu kB\n"
93 "DirtyThresh: %8lu kB\n"
f09b00d3 » Jens Axboe
2009-05-25 writeback: add some debug inode list counters to bdi stats
94 "BackgroundThresh: %8lu kB\n"
95 "b_dirty: %8lu\n"
96 "b_io: %8lu\n"
97 "b_more_io: %8lu\n"
98 "bdi_list: %8u\n"
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
99 "state: %8lx\n",
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
100 (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)),
101 (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)),
f09b00d3 » Jens Axboe
2009-05-25 writeback: add some debug inode list counters to bdi stats
102 K(bdi_thresh), K(dirty_thresh),
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
103 K(background_thresh), nr_dirty, nr_io, nr_more_io,
104 !list_empty(&bdi->bdi_list), bdi->state);
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
105 #undef K
106
107 return 0;
108 }
109
110 static int bdi_debug_stats_open(struct inode *inode, struct file *file)
111 {
112 return single_open(file, bdi_debug_stats_show, inode->i_private);
113 }
114
115 static const struct file_operations bdi_debug_stats_fops = {
116 .open = bdi_debug_stats_open,
117 .read = seq_read,
118 .llseek = seq_lseek,
119 .release = single_release,
120 };
121
122 static void bdi_debug_register(struct backing_dev_info *bdi, const char *name)
123 {
124 bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root);
125 bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir,
126 bdi, &bdi_debug_stats_fops);
127 }
128
129 static void bdi_debug_unregister(struct backing_dev_info *bdi)
130 {
131 debugfs_remove(bdi->debug_stats);
132 debugfs_remove(bdi->debug_dir);
133 }
134 #else
135 static inline void bdi_debug_init(void)
136 {
137 }
138 static inline void bdi_debug_register(struct backing_dev_info *bdi,
139 const char *name)
140 {
141 }
142 static inline void bdi_debug_unregister(struct backing_dev_info *bdi)
143 {
144 }
145 #endif
146
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
147 static ssize_t read_ahead_kb_store(struct device *dev,
148 struct device_attribute *attr,
149 const char *buf, size_t count)
150 {
151 struct backing_dev_info *bdi = dev_get_drvdata(dev);
152 char *end;
153 unsigned long read_ahead_kb;
154 ssize_t ret = -EINVAL;
155
156 read_ahead_kb = simple_strtoul(buf, &end, 10);
157 if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
158 bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
159 ret = count;
160 }
161 return ret;
162 }
163
164 #define K(pages) ((pages) << (PAGE_SHIFT - 10))
165
166 #define BDI_SHOW(name, expr) \
167 static ssize_t name##_show(struct device *dev, \
168 struct device_attribute *attr, char *page) \
169 { \
170 struct backing_dev_info *bdi = dev_get_drvdata(dev); \
171 \
172 return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \
173 }
174
175 BDI_SHOW(read_ahead_kb, K(bdi->ra_pages))
176
189d3c4a » Peter Zijlstra
2008-04-30 mm: bdi: allow setting a minimum for the bdi dirty limit
177 static ssize_t min_ratio_store(struct device *dev,
178 struct device_attribute *attr, const char *buf, size_t count)
179 {
180 struct backing_dev_info *bdi = dev_get_drvdata(dev);
181 char *end;
182 unsigned int ratio;
183 ssize_t ret = -EINVAL;
184
185 ratio = simple_strtoul(buf, &end, 10);
186 if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
187 ret = bdi_set_min_ratio(bdi, ratio);
188 if (!ret)
189 ret = count;
190 }
191 return ret;
192 }
193 BDI_SHOW(min_ratio, bdi->min_ratio)
194
a42dde04 » Peter Zijlstra
2008-04-30 mm: bdi: allow setting a maximum for the bdi dirty limit
195 static ssize_t max_ratio_store(struct device *dev,
196 struct device_attribute *attr, const char *buf, size_t count)
197 {
198 struct backing_dev_info *bdi = dev_get_drvdata(dev);
199 char *end;
200 unsigned int ratio;
201 ssize_t ret = -EINVAL;
202
203 ratio = simple_strtoul(buf, &end, 10);
204 if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
205 ret = bdi_set_max_ratio(bdi, ratio);
206 if (!ret)
207 ret = count;
208 }
209 return ret;
210 }
211 BDI_SHOW(max_ratio, bdi->max_ratio)
212
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
213 #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
214
215 static struct device_attribute bdi_dev_attrs[] = {
216 __ATTR_RW(read_ahead_kb),
189d3c4a » Peter Zijlstra
2008-04-30 mm: bdi: allow setting a minimum for the bdi dirty limit
217 __ATTR_RW(min_ratio),
a42dde04 » Peter Zijlstra
2008-04-30 mm: bdi: allow setting a maximum for the bdi dirty limit
218 __ATTR_RW(max_ratio),
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
219 __ATTR_NULL,
220 };
221
222 static __init int bdi_class_init(void)
223 {
224 bdi_class = class_create(THIS_MODULE, "bdi");
14421453 » antonblanchard
2010-04-02 backing-dev: Handle class_create() failure
225 if (IS_ERR(bdi_class))
226 return PTR_ERR(bdi_class);
227
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
228 bdi_class->dev_attrs = bdi_dev_attrs;
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
229 bdi_debug_init();
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
230 return 0;
231 }
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
232 postcore_initcall(bdi_class_init);
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
233
26160158 » Jens Axboe
2009-03-17 Move the default_backing_dev_info out of readahead.c and into backing…
234 static int __init default_bdi_init(void)
235 {
236 int err;
237
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
238 sync_supers_tsk = kthread_run(bdi_sync_supers, NULL, "sync_supers");
239 BUG_ON(IS_ERR(sync_supers_tsk));
240
241 init_timer(&sync_supers_timer);
242 setup_timer(&sync_supers_timer, sync_supers_timer_fn, 0);
6423104b » Jens Axboe
2010-05-21 writeback: fixups for !dirty_writeback_centisecs
243 bdi_arm_supers_timer();
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
244
26160158 » Jens Axboe
2009-03-17 Move the default_backing_dev_info out of readahead.c and into backing…
245 err = bdi_init(&default_backing_dev_info);
246 if (!err)
247 bdi_register(&default_backing_dev_info, NULL, "default");
248
249 return err;
250 }
251 subsys_initcall(default_bdi_init);
252
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
253 static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
254 {
255 memset(wb, 0, sizeof(*wb));
256
257 wb->bdi = bdi;
258 wb->last_old_flush = jiffies;
259 INIT_LIST_HEAD(&wb->b_dirty);
260 INIT_LIST_HEAD(&wb->b_io);
261 INIT_LIST_HEAD(&wb->b_more_io);
262 }
263
264 int bdi_has_dirty_io(struct backing_dev_info *bdi)
265 {
266 return wb_has_dirty_io(&bdi->wb);
267 }
268
269 static void bdi_flush_io(struct backing_dev_info *bdi)
270 {
271 struct writeback_control wbc = {
272 .sync_mode = WB_SYNC_NONE,
273 .older_than_this = NULL,
274 .range_cyclic = 1,
275 .nr_to_write = 1024,
276 };
277
9c3a8ee8 » Christoph Hellwig
2010-06-10 writeback: remove writeback_inodes_wbc
278 writeback_inodes_wb(&bdi->wb, &wbc);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
279 }
280
281 /*
282 * kupdated() used to do this. We cannot do it from the bdi_forker_task()
283 * or we risk deadlocking on ->s_umount. The longer term solution would be
284 * to implement sync_supers_bdi() or similar and simply do it from the
285 * bdi writeback tasks individually.
286 */
287 static int bdi_sync_supers(void *unused)
288 {
289 set_user_nice(current, 0);
290
291 while (!kthread_should_stop()) {
292 set_current_state(TASK_INTERRUPTIBLE);
293 schedule();
294
295 /*
296 * Do this periodically, like kupdated() did before.
297 */
298 sync_supers();
299 }
300
301 return 0;
302 }
303
6423104b » Jens Axboe
2010-05-21 writeback: fixups for !dirty_writeback_centisecs
304 void bdi_arm_supers_timer(void)
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
305 {
306 unsigned long next;
307
6423104b » Jens Axboe
2010-05-21 writeback: fixups for !dirty_writeback_centisecs
308 if (!dirty_writeback_interval)
309 return;
310
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
311 next = msecs_to_jiffies(dirty_writeback_interval * 10) + jiffies;
312 mod_timer(&sync_supers_timer, round_jiffies_up(next));
313 }
314
315 static void sync_supers_timer_fn(unsigned long unused)
316 {
317 wake_up_process(sync_supers_tsk);
6423104b » Jens Axboe
2010-05-21 writeback: fixups for !dirty_writeback_centisecs
318 bdi_arm_supers_timer();
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
319 }
320
321 static int bdi_forker_task(void *ptr)
322 {
323 struct bdi_writeback *me = ptr;
324
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
325 current->flags |= PF_FLUSHER | PF_SWAPWRITE;
326 set_freezable();
327
328 /*
329 * Our parent may run at a different priority, just set us to normal
330 */
331 set_user_nice(current, 0);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
332
333 for (;;) {
334 struct backing_dev_info *bdi, *tmp;
335 struct bdi_writeback *wb;
336
337 /*
338 * Temporary measure, we want to make sure we don't see
339 * dirty data on the default backing_dev_info
340 */
341 if (wb_has_dirty_io(me) || !list_empty(&me->bdi->work_list))
342 wb_do_writeback(me, 0);
343
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
344 spin_lock_bh(&bdi_lock);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
345
346 /*
347 * Check if any existing bdi's have dirty data without
348 * a thread registered. If so, set that up.
349 */
350 list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) {
351 if (bdi->wb.task)
352 continue;
353 if (list_empty(&bdi->work_list) &&
354 !bdi_has_dirty_io(bdi))
355 continue;
356
357 bdi_add_default_flusher_task(bdi);
358 }
359
360 set_current_state(TASK_INTERRUPTIBLE);
361
362 if (list_empty(&bdi_pending_list)) {
363 unsigned long wait;
364
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
365 spin_unlock_bh(&bdi_lock);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
366 wait = msecs_to_jiffies(dirty_writeback_interval * 10);
6423104b » Jens Axboe
2010-05-21 writeback: fixups for !dirty_writeback_centisecs
367 if (wait)
368 schedule_timeout(wait);
369 else
370 schedule();
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
371 try_to_freeze();
372 continue;
373 }
374
375 __set_current_state(TASK_RUNNING);
376
377 /*
378 * This is our real job - check for pending entries in
379 * bdi_pending_list, and create the tasks that got added
380 */
381 bdi = list_entry(bdi_pending_list.next, struct backing_dev_info,
382 bdi_list);
383 list_del_init(&bdi->bdi_list);
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
384 spin_unlock_bh(&bdi_lock);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
385
386 wb = &bdi->wb;
08243900 » Christoph Hellwig
2010-06-19 writeback: merge bdi_writeback_task and bdi_start_fn
387 wb->task = kthread_run(bdi_writeback_thread, wb, "flush-%s",
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
388 dev_name(bdi->dev));
389 /*
390 * If task creation fails, then readd the bdi to
391 * the pending list and force writeout of the bdi
392 * from this forker thread. That will free some memory
393 * and we can try again.
394 */
395 if (IS_ERR(wb->task)) {
396 wb->task = NULL;
397
398 /*
399 * Add this 'bdi' to the back, so we get
400 * a chance to flush other bdi's to free
401 * memory.
402 */
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
403 spin_lock_bh(&bdi_lock);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
404 list_add_tail(&bdi->bdi_list, &bdi_pending_list);
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
405 spin_unlock_bh(&bdi_lock);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
406
407 bdi_flush_io(bdi);
408 }
409 }
410
411 return 0;
412 }
413
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
414 static void bdi_add_to_pending(struct rcu_head *head)
415 {
416 struct backing_dev_info *bdi;
417
418 bdi = container_of(head, struct backing_dev_info, rcu_head);
419 INIT_LIST_HEAD(&bdi->bdi_list);
420
421 spin_lock(&bdi_lock);
422 list_add_tail(&bdi->bdi_list, &bdi_pending_list);
423 spin_unlock(&bdi_lock);
424
425 /*
426 * We are now on the pending list, wake up bdi_forker_task()
427 * to finish the job and add us back to the active bdi_list
428 */
429 wake_up_process(default_backing_dev_info.wb.task);
430 }
431
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
432 /*
433 * Add the default flusher task that gets created for any bdi
434 * that has dirty data pending writeout
435 */
436 void static bdi_add_default_flusher_task(struct backing_dev_info *bdi)
437 {
438 if (!bdi_cap_writeback_dirty(bdi))
439 return;
440
500b067c » Jens Axboe
2009-09-09 writeback: check for registered bdi in flusher add and inode dirty
441 if (WARN_ON(!test_bit(BDI_registered, &bdi->state))) {
442 printk(KERN_ERR "bdi %p/%s is not registered!\n",
443 bdi, bdi->name);
444 return;
445 }
446
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
447 /*
448 * Check with the helper whether to proceed adding a task. Will only
449 * abort if we two or more simultanous calls to
450 * bdi_add_default_flusher_task() occured, further additions will block
451 * waiting for previous additions to finish.
452 */
453 if (!test_and_set_bit(BDI_pending, &bdi->state)) {
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
454 list_del_rcu(&bdi->bdi_list);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
455
456 /*
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
457 * We must wait for the current RCU period to end before
458 * moving to the pending list. So schedule that operation
459 * from an RCU callback.
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
460 */
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
461 call_rcu(&bdi->rcu_head, bdi_add_to_pending);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
462 }
463 }
464
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
465 /*
466 * Remove bdi from bdi_list, and ensure that it is no longer visible
467 */
468 static void bdi_remove_from_list(struct backing_dev_info *bdi)
469 {
470 spin_lock_bh(&bdi_lock);
471 list_del_rcu(&bdi->bdi_list);
472 spin_unlock_bh(&bdi_lock);
473
474 synchronize_rcu();
475 }
476
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
477 int bdi_register(struct backing_dev_info *bdi, struct device *parent,
478 const char *fmt, ...)
479 {
480 va_list args;
481 int ret = 0;
482 struct device *dev;
483
69fc208b » Andrew Morton
2008-12-09 mm/backing-dev.c: remove recently-added WARN_ON()
484 if (bdi->dev) /* The driver needs to use separate queues per device */
f1d0b063 » kaysievers
2008-12-02 bdi: register sysfs bdi device only once per queue
485 goto exit;
486
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
487 va_start(args, fmt);
19051c50 » gregkh
2008-05-15 mm: bdi: fix race in bdi_class device creation
488 dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
489 va_end(args);
490 if (IS_ERR(dev)) {
491 ret = PTR_ERR(dev);
492 goto exit;
493 }
494
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
495 spin_lock_bh(&bdi_lock);
496 list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
497 spin_unlock_bh(&bdi_lock);
66f3b8e2 » Jens Axboe
2009-09-02 writeback: move dirty inodes from super_block to backing_dev_info
498
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
499 bdi->dev = dev;
500
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
501 /*
502 * Just start the forker thread for our default backing_dev_info,
503 * and add other bdi's to the list. They will get a thread created
504 * on-demand when they need it.
505 */
506 if (bdi_cap_flush_forker(bdi)) {
507 struct bdi_writeback *wb = &bdi->wb;
508
509 wb->task = kthread_run(bdi_forker_task, wb, "bdi-%s",
510 dev_name(dev));
511 if (IS_ERR(wb->task)) {
512 wb->task = NULL;
513 ret = -ENOMEM;
514
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
515 bdi_remove_from_list(bdi);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
516 goto exit;
517 }
518 }
519
520 bdi_debug_register(bdi, dev_name(dev));
500b067c » Jens Axboe
2009-09-09 writeback: check for registered bdi in flusher add and inode dirty
521 set_bit(BDI_registered, &bdi->state);
455b2864 » dchinner
2010-07-07 writeback: Initial tracing support
522 trace_writeback_bdi_register(bdi);
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
523 exit:
524 return ret;
525 }
526 EXPORT_SYMBOL(bdi_register);
527
528 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
529 {
530 return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
531 }
532 EXPORT_SYMBOL(bdi_register_dev);
533
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
534 /*
535 * Remove bdi from the global list and shutdown any threads we have running
536 */
537 static void bdi_wb_shutdown(struct backing_dev_info *bdi)
66f3b8e2 » Jens Axboe
2009-09-02 writeback: move dirty inodes from super_block to backing_dev_info
538 {
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
539 if (!bdi_cap_writeback_dirty(bdi))
540 return;
541
542 /*
543 * If setup is pending, wait for that to complete first
544 */
545 wait_on_bit(&bdi->state, BDI_pending, bdi_sched_wait,
546 TASK_UNINTERRUPTIBLE);
547
548 /*
549 * Make sure nobody finds us on the bdi_list anymore
550 */
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
551 bdi_remove_from_list(bdi);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
552
553 /*
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
554 * Finally, kill the kernel thread. We don't need to be RCU
c62b17a5 » Romit Dasgupta
2009-11-12 Thaw refrigerated bdi flusher threads before invoking kthread_stop on…
555 * safe anymore, since the bdi is gone from visibility. Force
556 * unfreeze of the thread before calling kthread_stop(), otherwise
557 * it would never exet if it is currently stuck in the refrigerator.
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
558 */
c1955ce3 » Christoph Hellwig
2010-06-19 writeback: remove wb_list
559 if (bdi->wb.task) {
560 thaw_process(bdi->wb.task);
561 kthread_stop(bdi->wb.task);
c62b17a5 » Romit Dasgupta
2009-11-12 Thaw refrigerated bdi flusher threads before invoking kthread_stop on…
562 }
66f3b8e2 » Jens Axboe
2009-09-02 writeback: move dirty inodes from super_block to backing_dev_info
563 }
564
592b09a4 » Jens Axboe
2009-10-29 backing-dev: ensure that a removed bdi no longer has super_block refe…
565 /*
566 * This bdi is going away now, make sure that no super_blocks point to it
567 */
568 static void bdi_prune_sb(struct backing_dev_info *bdi)
569 {
570 struct super_block *sb;
571
572 spin_lock(&sb_lock);
573 list_for_each_entry(sb, &super_blocks, s_list) {
574 if (sb->s_bdi == bdi)
575 sb->s_bdi = NULL;
576 }
577 spin_unlock(&sb_lock);
578 }
579
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
580 void bdi_unregister(struct backing_dev_info *bdi)
581 {
582 if (bdi->dev) {
455b2864 » dchinner
2010-07-07 writeback: Initial tracing support
583 trace_writeback_bdi_unregister(bdi);
8c4db335 » Jens Axboe
2009-11-03 backing-dev: bdi sb prune should be in the unregister path, not destroy
584 bdi_prune_sb(bdi);
585
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
586 if (!bdi_cap_flush_forker(bdi))
587 bdi_wb_shutdown(bdi);
76f1418b » Miklos Szeredi
2008-04-30 mm: bdi: move statistics to debugfs
588 bdi_debug_unregister(bdi);
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
589 device_unregister(bdi->dev);
590 bdi->dev = NULL;
591 }
592 }
593 EXPORT_SYMBOL(bdi_unregister);
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
594
b2e8fb6e » Peter Zijlstra
2007-10-16 mm: scalable bdi statistics counters
595 int bdi_init(struct backing_dev_info *bdi)
596 {
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
597 int i, err;
b2e8fb6e » Peter Zijlstra
2007-10-16 mm: scalable bdi statistics counters
598
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
599 bdi->dev = NULL;
600
189d3c4a » Peter Zijlstra
2008-04-30 mm: bdi: allow setting a minimum for the bdi dirty limit
601 bdi->min_ratio = 0;
a42dde04 » Peter Zijlstra
2008-04-30 mm: bdi: allow setting a maximum for the bdi dirty limit
602 bdi->max_ratio = 100;
603 bdi->max_prop_frac = PROP_FRAC_BASE;
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
604 spin_lock_init(&bdi->wb_lock);
cfc4ba53 » Jens Axboe
2009-09-14 writeback: use RCU to protect bdi_list
605 INIT_RCU_HEAD(&bdi->rcu_head);
66f3b8e2 » Jens Axboe
2009-09-02 writeback: move dirty inodes from super_block to backing_dev_info
606 INIT_LIST_HEAD(&bdi->bdi_list);
03ba3782 » Jens Axboe
2009-09-09 writeback: switch to per-bdi threads for flushing data
607 INIT_LIST_HEAD(&bdi->work_list);
608
609 bdi_wb_init(&bdi->wb, bdi);
610
b2e8fb6e » Peter Zijlstra
2007-10-16 mm: scalable bdi statistics counters
611 for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
ea319518 » Peter Zijlstra
2008-12-26 locking, percpu counters: introduce separate lock classes
612 err = percpu_counter_init(&bdi->bdi_stat[i], 0);
04fbfdc1 » Peter Zijlstra
2007-10-16 mm: per device dirty threshold
613 if (err)
614 goto err;
615 }
616
617 bdi->dirty_exceeded = 0;
618 err = prop_local_init_percpu(&bdi->completions);
619
620 if (err) {
621 err:
4b01a0b1 » crquan
2007-12-04 mm/backing-dev.c: fix percpu_counter_destroy call bug in bdi_init
622 while (i--)
04fbfdc1 » Peter Zijlstra
2007-10-16 mm: per device dirty threshold
623 percpu_counter_destroy(&bdi->bdi_stat[i]);
b2e8fb6e » Peter Zijlstra
2007-10-16 mm: scalable bdi statistics counters
624 }
625
626 return err;
627 }
628 EXPORT_SYMBOL(bdi_init);
629
630 void bdi_destroy(struct backing_dev_info *bdi)
631 {
632 int i;
633
ce5f8e77 » Jens Axboe
2009-09-14 writeback: splice dirty inode entries to default bdi on bdi_destroy()
634 /*
635 * Splice our entries to the default_backing_dev_info, if this
636 * bdi disappears
637 */
638 if (bdi_has_dirty_io(bdi)) {
639 struct bdi_writeback *dst = &default_backing_dev_info.wb;
640
641 spin_lock(&inode_lock);
642 list_splice(&bdi->wb.b_dirty, &dst->b_dirty);
643 list_splice(&bdi->wb.b_io, &dst->b_io);
644 list_splice(&bdi->wb.b_more_io, &dst->b_more_io);
645 spin_unlock(&inode_lock);
646 }
66f3b8e2 » Jens Axboe
2009-09-02 writeback: move dirty inodes from super_block to backing_dev_info
647
cf0ca9fe » Peter Zijlstra
2008-04-30 mm: bdi: export BDI attributes in sysfs
648 bdi_unregister(bdi);
649
b2e8fb6e » Peter Zijlstra
2007-10-16 mm: scalable bdi statistics counters
650 for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
651 percpu_counter_destroy(&bdi->bdi_stat[i]);
04fbfdc1 » Peter Zijlstra
2007-10-16 mm: per device dirty threshold
652
653 prop_local_destroy_percpu(&bdi->completions);
b2e8fb6e » Peter Zijlstra
2007-10-16 mm: scalable bdi statistics counters
654 }
655 EXPORT_SYMBOL(bdi_destroy);
656
c3c53206 » Jens Axboe
2010-04-22 bdi: add helper function for doing init and register of a bdi for a f…
657 /*
658 * For use from filesystems to quickly init and register a bdi associated
659 * with dirty writeback
660 */
661 int bdi_setup_and_register(struct backing_dev_info *bdi, char *name,
662 unsigned int cap)
663 {
664 char tmp[32];
665 int err;
666
667 bdi->name = name;
668 bdi->capabilities = cap;
669 err = bdi_init(bdi);
670 if (err)
671 return err;
672
673 sprintf(tmp, "%.28s%s", name, "-%d");
674 err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq));
675 if (err) {
676 bdi_destroy(bdi);
677 return err;
678 }
679
680 return 0;
681 }
682 EXPORT_SYMBOL(bdi_setup_and_register);
683
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
684 static wait_queue_head_t congestion_wqh[2] = {
685 __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
686 __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
687 };
688
1faa16d2 » Jens Axboe
2009-04-06 block: change the request allocation/congestion logic to be sync/asyn…
689 void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
690 {
691 enum bdi_state bit;
1faa16d2 » Jens Axboe
2009-04-06 block: change the request allocation/congestion logic to be sync/asyn…
692 wait_queue_head_t *wqh = &congestion_wqh[sync];
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
693
1faa16d2 » Jens Axboe
2009-04-06 block: change the request allocation/congestion logic to be sync/asyn…
694 bit = sync ? BDI_sync_congested : BDI_async_congested;
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
695 clear_bit(bit, &bdi->state);
696 smp_mb__after_clear_bit();
697 if (waitqueue_active(wqh))
698 wake_up(wqh);
699 }
700 EXPORT_SYMBOL(clear_bdi_congested);
701
1faa16d2 » Jens Axboe
2009-04-06 block: change the request allocation/congestion logic to be sync/asyn…
702 void set_bdi_congested(struct backing_dev_info *bdi, int sync)
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
703 {
704 enum bdi_state bit;
705
1faa16d2 » Jens Axboe
2009-04-06 block: change the request allocation/congestion logic to be sync/asyn…
706 bit = sync ? BDI_sync_congested : BDI_async_congested;
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
707 set_bit(bit, &bdi->state);
708 }
709 EXPORT_SYMBOL(set_bdi_congested);
710
711 /**
712 * congestion_wait - wait for a backing_dev to become uncongested
8aa7e847 » Jens Axboe
2009-07-09 Fix congestion_wait() sync/async vs read/write confusion
713 * @sync: SYNC or ASYNC IO
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
714 * @timeout: timeout in jiffies
715 *
716 * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit
717 * write congestion. If no backing_devs are congested then just wait for the
718 * next write to be completed.
719 */
8aa7e847 » Jens Axboe
2009-07-09 Fix congestion_wait() sync/async vs read/write confusion
720 long congestion_wait(int sync, long timeout)
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
721 {
722 long ret;
723 DEFINE_WAIT(wait);
8aa7e847 » Jens Axboe
2009-07-09 Fix congestion_wait() sync/async vs read/write confusion
724 wait_queue_head_t *wqh = &congestion_wqh[sync];
3fcfab16 » Andrew Morton
2006-10-19 [PATCH] separate bdi congestion functions from queue congestion funct…
725
726 prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
727 ret = io_schedule_timeout(timeout);
728 finish_wait(wqh, &wait);
729 return ret;
730 }
731 EXPORT_SYMBOL(congestion_wait);
04fbfdc1 » Peter Zijlstra
2007-10-16 mm: per device dirty threshold
732
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