Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 1 | |
| 2 | #include <linux/wait.h> |
| 3 | #include <linux/backing-dev.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 4 | #include <linux/kthread.h> |
| 5 | #include <linux/freezer.h> |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 6 | #include <linux/fs.h> |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 7 | #include <linux/pagemap.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 8 | #include <linux/mm.h> |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 9 | #include <linux/sched.h> |
| 10 | #include <linux/module.h> |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 11 | #include <linux/writeback.h> |
| 12 | #include <linux/device.h> |
| 13 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 14 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
| 15 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 16 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
| 17 | { |
| 18 | } |
| 19 | EXPORT_SYMBOL(default_unplug_io_fn); |
| 20 | |
| 21 | struct backing_dev_info default_backing_dev_info = { |
Jens Axboe | d993831 | 2009-06-12 14:45:52 +0200 | [diff] [blame] | 22 | .name = "default", |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 23 | .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE, |
| 24 | .state = 0, |
| 25 | .capabilities = BDI_CAP_MAP_COPY, |
| 26 | .unplug_io_fn = default_unplug_io_fn, |
| 27 | }; |
| 28 | EXPORT_SYMBOL_GPL(default_backing_dev_info); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 29 | |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 30 | struct backing_dev_info noop_backing_dev_info = { |
| 31 | .name = "noop", |
| 32 | }; |
| 33 | EXPORT_SYMBOL_GPL(noop_backing_dev_info); |
| 34 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 35 | static struct class *bdi_class; |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 36 | |
| 37 | /* |
| 38 | * bdi_lock protects updates to bdi_list and bdi_pending_list, as well as |
| 39 | * reader side protection for bdi_pending_list. bdi_list has RCU reader side |
| 40 | * locking. |
| 41 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 42 | DEFINE_SPINLOCK(bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 43 | LIST_HEAD(bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 44 | LIST_HEAD(bdi_pending_list); |
| 45 | |
| 46 | static struct task_struct *sync_supers_tsk; |
| 47 | static struct timer_list sync_supers_timer; |
| 48 | |
| 49 | static int bdi_sync_supers(void *); |
| 50 | static void sync_supers_timer_fn(unsigned long); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 51 | |
| 52 | static void bdi_add_default_flusher_task(struct backing_dev_info *bdi); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 53 | |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 54 | #ifdef CONFIG_DEBUG_FS |
| 55 | #include <linux/debugfs.h> |
| 56 | #include <linux/seq_file.h> |
| 57 | |
| 58 | static struct dentry *bdi_debug_root; |
| 59 | |
| 60 | static void bdi_debug_init(void) |
| 61 | { |
| 62 | bdi_debug_root = debugfs_create_dir("bdi", NULL); |
| 63 | } |
| 64 | |
| 65 | static int bdi_debug_stats_show(struct seq_file *m, void *v) |
| 66 | { |
| 67 | struct backing_dev_info *bdi = m->private; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 68 | struct bdi_writeback *wb; |
David Rientjes | 364aeb2 | 2009-01-06 14:39:29 -0800 | [diff] [blame] | 69 | unsigned long background_thresh; |
| 70 | unsigned long dirty_thresh; |
| 71 | unsigned long bdi_thresh; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 72 | unsigned long nr_dirty, nr_io, nr_more_io, nr_wb; |
| 73 | struct inode *inode; |
| 74 | |
| 75 | /* |
| 76 | * inode lock is enough here, the bdi->wb_list is protected by |
| 77 | * RCU on the reader side |
| 78 | */ |
| 79 | nr_wb = nr_dirty = nr_io = nr_more_io = 0; |
| 80 | spin_lock(&inode_lock); |
| 81 | list_for_each_entry(wb, &bdi->wb_list, list) { |
| 82 | nr_wb++; |
| 83 | list_for_each_entry(inode, &wb->b_dirty, i_list) |
| 84 | nr_dirty++; |
| 85 | list_for_each_entry(inode, &wb->b_io, i_list) |
| 86 | nr_io++; |
| 87 | list_for_each_entry(inode, &wb->b_more_io, i_list) |
| 88 | nr_more_io++; |
| 89 | } |
| 90 | spin_unlock(&inode_lock); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 91 | |
| 92 | get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi); |
| 93 | |
| 94 | #define K(x) ((x) << (PAGE_SHIFT - 10)) |
| 95 | seq_printf(m, |
| 96 | "BdiWriteback: %8lu kB\n" |
| 97 | "BdiReclaimable: %8lu kB\n" |
| 98 | "BdiDirtyThresh: %8lu kB\n" |
| 99 | "DirtyThresh: %8lu kB\n" |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 100 | "BackgroundThresh: %8lu kB\n" |
Wu Fengguang | 961515f | 2009-10-09 13:01:27 +0200 | [diff] [blame] | 101 | "WritebackThreads: %8lu\n" |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 102 | "b_dirty: %8lu\n" |
| 103 | "b_io: %8lu\n" |
| 104 | "b_more_io: %8lu\n" |
| 105 | "bdi_list: %8u\n" |
| 106 | "state: %8lx\n" |
| 107 | "wb_mask: %8lx\n" |
| 108 | "wb_list: %8u\n" |
| 109 | "wb_cnt: %8u\n", |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 110 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), |
| 111 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 112 | K(bdi_thresh), K(dirty_thresh), |
| 113 | K(background_thresh), nr_wb, nr_dirty, nr_io, nr_more_io, |
| 114 | !list_empty(&bdi->bdi_list), bdi->state, bdi->wb_mask, |
| 115 | !list_empty(&bdi->wb_list), bdi->wb_cnt); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 116 | #undef K |
| 117 | |
| 118 | return 0; |
| 119 | } |
| 120 | |
| 121 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) |
| 122 | { |
| 123 | return single_open(file, bdi_debug_stats_show, inode->i_private); |
| 124 | } |
| 125 | |
| 126 | static const struct file_operations bdi_debug_stats_fops = { |
| 127 | .open = bdi_debug_stats_open, |
| 128 | .read = seq_read, |
| 129 | .llseek = seq_lseek, |
| 130 | .release = single_release, |
| 131 | }; |
| 132 | |
| 133 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) |
| 134 | { |
| 135 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); |
| 136 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, |
| 137 | bdi, &bdi_debug_stats_fops); |
| 138 | } |
| 139 | |
| 140 | static void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 141 | { |
| 142 | debugfs_remove(bdi->debug_stats); |
| 143 | debugfs_remove(bdi->debug_dir); |
| 144 | } |
| 145 | #else |
| 146 | static inline void bdi_debug_init(void) |
| 147 | { |
| 148 | } |
| 149 | static inline void bdi_debug_register(struct backing_dev_info *bdi, |
| 150 | const char *name) |
| 151 | { |
| 152 | } |
| 153 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 154 | { |
| 155 | } |
| 156 | #endif |
| 157 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 158 | static ssize_t read_ahead_kb_store(struct device *dev, |
| 159 | struct device_attribute *attr, |
| 160 | const char *buf, size_t count) |
| 161 | { |
| 162 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 163 | char *end; |
| 164 | unsigned long read_ahead_kb; |
| 165 | ssize_t ret = -EINVAL; |
| 166 | |
| 167 | read_ahead_kb = simple_strtoul(buf, &end, 10); |
| 168 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { |
| 169 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); |
| 170 | ret = count; |
| 171 | } |
| 172 | return ret; |
| 173 | } |
| 174 | |
| 175 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) |
| 176 | |
| 177 | #define BDI_SHOW(name, expr) \ |
| 178 | static ssize_t name##_show(struct device *dev, \ |
| 179 | struct device_attribute *attr, char *page) \ |
| 180 | { \ |
| 181 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ |
| 182 | \ |
| 183 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ |
| 184 | } |
| 185 | |
| 186 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) |
| 187 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 188 | static ssize_t min_ratio_store(struct device *dev, |
| 189 | struct device_attribute *attr, const char *buf, size_t count) |
| 190 | { |
| 191 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 192 | char *end; |
| 193 | unsigned int ratio; |
| 194 | ssize_t ret = -EINVAL; |
| 195 | |
| 196 | ratio = simple_strtoul(buf, &end, 10); |
| 197 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { |
| 198 | ret = bdi_set_min_ratio(bdi, ratio); |
| 199 | if (!ret) |
| 200 | ret = count; |
| 201 | } |
| 202 | return ret; |
| 203 | } |
| 204 | BDI_SHOW(min_ratio, bdi->min_ratio) |
| 205 | |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 206 | static ssize_t max_ratio_store(struct device *dev, |
| 207 | struct device_attribute *attr, const char *buf, size_t count) |
| 208 | { |
| 209 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 210 | char *end; |
| 211 | unsigned int ratio; |
| 212 | ssize_t ret = -EINVAL; |
| 213 | |
| 214 | ratio = simple_strtoul(buf, &end, 10); |
| 215 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { |
| 216 | ret = bdi_set_max_ratio(bdi, ratio); |
| 217 | if (!ret) |
| 218 | ret = count; |
| 219 | } |
| 220 | return ret; |
| 221 | } |
| 222 | BDI_SHOW(max_ratio, bdi->max_ratio) |
| 223 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 224 | #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) |
| 225 | |
| 226 | static struct device_attribute bdi_dev_attrs[] = { |
| 227 | __ATTR_RW(read_ahead_kb), |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 228 | __ATTR_RW(min_ratio), |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 229 | __ATTR_RW(max_ratio), |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 230 | __ATTR_NULL, |
| 231 | }; |
| 232 | |
| 233 | static __init int bdi_class_init(void) |
| 234 | { |
| 235 | bdi_class = class_create(THIS_MODULE, "bdi"); |
Anton Blanchard | 1442145 | 2010-04-02 09:46:55 +0200 | [diff] [blame] | 236 | if (IS_ERR(bdi_class)) |
| 237 | return PTR_ERR(bdi_class); |
| 238 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 239 | bdi_class->dev_attrs = bdi_dev_attrs; |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 240 | bdi_debug_init(); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 241 | return 0; |
| 242 | } |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 243 | postcore_initcall(bdi_class_init); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 244 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 245 | static int __init default_bdi_init(void) |
| 246 | { |
| 247 | int err; |
| 248 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 249 | sync_supers_tsk = kthread_run(bdi_sync_supers, NULL, "sync_supers"); |
| 250 | BUG_ON(IS_ERR(sync_supers_tsk)); |
| 251 | |
| 252 | init_timer(&sync_supers_timer); |
| 253 | setup_timer(&sync_supers_timer, sync_supers_timer_fn, 0); |
Jens Axboe | 6423104 | 2010-05-21 20:00:35 +0200 | [diff] [blame] | 254 | bdi_arm_supers_timer(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 255 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 256 | err = bdi_init(&default_backing_dev_info); |
| 257 | if (!err) |
| 258 | bdi_register(&default_backing_dev_info, NULL, "default"); |
| 259 | |
| 260 | return err; |
| 261 | } |
| 262 | subsys_initcall(default_bdi_init); |
| 263 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 264 | static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) |
| 265 | { |
| 266 | memset(wb, 0, sizeof(*wb)); |
| 267 | |
| 268 | wb->bdi = bdi; |
| 269 | wb->last_old_flush = jiffies; |
| 270 | INIT_LIST_HEAD(&wb->b_dirty); |
| 271 | INIT_LIST_HEAD(&wb->b_io); |
| 272 | INIT_LIST_HEAD(&wb->b_more_io); |
| 273 | } |
| 274 | |
| 275 | static void bdi_task_init(struct backing_dev_info *bdi, |
| 276 | struct bdi_writeback *wb) |
| 277 | { |
| 278 | struct task_struct *tsk = current; |
| 279 | |
| 280 | spin_lock(&bdi->wb_lock); |
| 281 | list_add_tail_rcu(&wb->list, &bdi->wb_list); |
| 282 | spin_unlock(&bdi->wb_lock); |
| 283 | |
| 284 | tsk->flags |= PF_FLUSHER | PF_SWAPWRITE; |
| 285 | set_freezable(); |
| 286 | |
| 287 | /* |
| 288 | * Our parent may run at a different priority, just set us to normal |
| 289 | */ |
| 290 | set_user_nice(tsk, 0); |
| 291 | } |
| 292 | |
| 293 | static int bdi_start_fn(void *ptr) |
| 294 | { |
| 295 | struct bdi_writeback *wb = ptr; |
| 296 | struct backing_dev_info *bdi = wb->bdi; |
| 297 | int ret; |
| 298 | |
| 299 | /* |
| 300 | * Add us to the active bdi_list |
| 301 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 302 | spin_lock_bh(&bdi_lock); |
| 303 | list_add_rcu(&bdi->bdi_list, &bdi_list); |
| 304 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 305 | |
| 306 | bdi_task_init(bdi, wb); |
| 307 | |
| 308 | /* |
| 309 | * Clear pending bit and wakeup anybody waiting to tear us down |
| 310 | */ |
| 311 | clear_bit(BDI_pending, &bdi->state); |
| 312 | smp_mb__after_clear_bit(); |
| 313 | wake_up_bit(&bdi->state, BDI_pending); |
| 314 | |
| 315 | ret = bdi_writeback_task(wb); |
| 316 | |
| 317 | /* |
| 318 | * Remove us from the list |
| 319 | */ |
| 320 | spin_lock(&bdi->wb_lock); |
| 321 | list_del_rcu(&wb->list); |
| 322 | spin_unlock(&bdi->wb_lock); |
| 323 | |
| 324 | /* |
| 325 | * Flush any work that raced with us exiting. No new work |
| 326 | * will be added, since this bdi isn't discoverable anymore. |
| 327 | */ |
| 328 | if (!list_empty(&bdi->work_list)) |
| 329 | wb_do_writeback(wb, 1); |
| 330 | |
| 331 | wb->task = NULL; |
| 332 | return ret; |
| 333 | } |
| 334 | |
| 335 | int bdi_has_dirty_io(struct backing_dev_info *bdi) |
| 336 | { |
| 337 | return wb_has_dirty_io(&bdi->wb); |
| 338 | } |
| 339 | |
| 340 | static void bdi_flush_io(struct backing_dev_info *bdi) |
| 341 | { |
| 342 | struct writeback_control wbc = { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 343 | .sync_mode = WB_SYNC_NONE, |
| 344 | .older_than_this = NULL, |
| 345 | .range_cyclic = 1, |
| 346 | .nr_to_write = 1024, |
| 347 | }; |
| 348 | |
Christoph Hellwig | 9c3a8ee | 2010-06-10 12:07:27 +0200 | [diff] [blame^] | 349 | writeback_inodes_wb(&bdi->wb, &wbc); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 350 | } |
| 351 | |
| 352 | /* |
| 353 | * kupdated() used to do this. We cannot do it from the bdi_forker_task() |
| 354 | * or we risk deadlocking on ->s_umount. The longer term solution would be |
| 355 | * to implement sync_supers_bdi() or similar and simply do it from the |
| 356 | * bdi writeback tasks individually. |
| 357 | */ |
| 358 | static int bdi_sync_supers(void *unused) |
| 359 | { |
| 360 | set_user_nice(current, 0); |
| 361 | |
| 362 | while (!kthread_should_stop()) { |
| 363 | set_current_state(TASK_INTERRUPTIBLE); |
| 364 | schedule(); |
| 365 | |
| 366 | /* |
| 367 | * Do this periodically, like kupdated() did before. |
| 368 | */ |
| 369 | sync_supers(); |
| 370 | } |
| 371 | |
| 372 | return 0; |
| 373 | } |
| 374 | |
Jens Axboe | 6423104 | 2010-05-21 20:00:35 +0200 | [diff] [blame] | 375 | void bdi_arm_supers_timer(void) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 376 | { |
| 377 | unsigned long next; |
| 378 | |
Jens Axboe | 6423104 | 2010-05-21 20:00:35 +0200 | [diff] [blame] | 379 | if (!dirty_writeback_interval) |
| 380 | return; |
| 381 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 382 | next = msecs_to_jiffies(dirty_writeback_interval * 10) + jiffies; |
| 383 | mod_timer(&sync_supers_timer, round_jiffies_up(next)); |
| 384 | } |
| 385 | |
| 386 | static void sync_supers_timer_fn(unsigned long unused) |
| 387 | { |
| 388 | wake_up_process(sync_supers_tsk); |
Jens Axboe | 6423104 | 2010-05-21 20:00:35 +0200 | [diff] [blame] | 389 | bdi_arm_supers_timer(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 390 | } |
| 391 | |
| 392 | static int bdi_forker_task(void *ptr) |
| 393 | { |
| 394 | struct bdi_writeback *me = ptr; |
| 395 | |
| 396 | bdi_task_init(me->bdi, me); |
| 397 | |
| 398 | for (;;) { |
| 399 | struct backing_dev_info *bdi, *tmp; |
| 400 | struct bdi_writeback *wb; |
| 401 | |
| 402 | /* |
| 403 | * Temporary measure, we want to make sure we don't see |
| 404 | * dirty data on the default backing_dev_info |
| 405 | */ |
| 406 | if (wb_has_dirty_io(me) || !list_empty(&me->bdi->work_list)) |
| 407 | wb_do_writeback(me, 0); |
| 408 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 409 | spin_lock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 410 | |
| 411 | /* |
| 412 | * Check if any existing bdi's have dirty data without |
| 413 | * a thread registered. If so, set that up. |
| 414 | */ |
| 415 | list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) { |
| 416 | if (bdi->wb.task) |
| 417 | continue; |
| 418 | if (list_empty(&bdi->work_list) && |
| 419 | !bdi_has_dirty_io(bdi)) |
| 420 | continue; |
| 421 | |
| 422 | bdi_add_default_flusher_task(bdi); |
| 423 | } |
| 424 | |
| 425 | set_current_state(TASK_INTERRUPTIBLE); |
| 426 | |
| 427 | if (list_empty(&bdi_pending_list)) { |
| 428 | unsigned long wait; |
| 429 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 430 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 431 | wait = msecs_to_jiffies(dirty_writeback_interval * 10); |
Jens Axboe | 6423104 | 2010-05-21 20:00:35 +0200 | [diff] [blame] | 432 | if (wait) |
| 433 | schedule_timeout(wait); |
| 434 | else |
| 435 | schedule(); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 436 | try_to_freeze(); |
| 437 | continue; |
| 438 | } |
| 439 | |
| 440 | __set_current_state(TASK_RUNNING); |
| 441 | |
| 442 | /* |
| 443 | * This is our real job - check for pending entries in |
| 444 | * bdi_pending_list, and create the tasks that got added |
| 445 | */ |
| 446 | bdi = list_entry(bdi_pending_list.next, struct backing_dev_info, |
| 447 | bdi_list); |
| 448 | list_del_init(&bdi->bdi_list); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 449 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 450 | |
| 451 | wb = &bdi->wb; |
| 452 | wb->task = kthread_run(bdi_start_fn, wb, "flush-%s", |
| 453 | dev_name(bdi->dev)); |
| 454 | /* |
| 455 | * If task creation fails, then readd the bdi to |
| 456 | * the pending list and force writeout of the bdi |
| 457 | * from this forker thread. That will free some memory |
| 458 | * and we can try again. |
| 459 | */ |
| 460 | if (IS_ERR(wb->task)) { |
| 461 | wb->task = NULL; |
| 462 | |
| 463 | /* |
| 464 | * Add this 'bdi' to the back, so we get |
| 465 | * a chance to flush other bdi's to free |
| 466 | * memory. |
| 467 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 468 | spin_lock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 469 | list_add_tail(&bdi->bdi_list, &bdi_pending_list); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 470 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 471 | |
| 472 | bdi_flush_io(bdi); |
| 473 | } |
| 474 | } |
| 475 | |
| 476 | return 0; |
| 477 | } |
| 478 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 479 | static void bdi_add_to_pending(struct rcu_head *head) |
| 480 | { |
| 481 | struct backing_dev_info *bdi; |
| 482 | |
| 483 | bdi = container_of(head, struct backing_dev_info, rcu_head); |
| 484 | INIT_LIST_HEAD(&bdi->bdi_list); |
| 485 | |
| 486 | spin_lock(&bdi_lock); |
| 487 | list_add_tail(&bdi->bdi_list, &bdi_pending_list); |
| 488 | spin_unlock(&bdi_lock); |
| 489 | |
| 490 | /* |
| 491 | * We are now on the pending list, wake up bdi_forker_task() |
| 492 | * to finish the job and add us back to the active bdi_list |
| 493 | */ |
| 494 | wake_up_process(default_backing_dev_info.wb.task); |
| 495 | } |
| 496 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 497 | /* |
| 498 | * Add the default flusher task that gets created for any bdi |
| 499 | * that has dirty data pending writeout |
| 500 | */ |
| 501 | void static bdi_add_default_flusher_task(struct backing_dev_info *bdi) |
| 502 | { |
| 503 | if (!bdi_cap_writeback_dirty(bdi)) |
| 504 | return; |
| 505 | |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 506 | if (WARN_ON(!test_bit(BDI_registered, &bdi->state))) { |
| 507 | printk(KERN_ERR "bdi %p/%s is not registered!\n", |
| 508 | bdi, bdi->name); |
| 509 | return; |
| 510 | } |
| 511 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 512 | /* |
| 513 | * Check with the helper whether to proceed adding a task. Will only |
| 514 | * abort if we two or more simultanous calls to |
| 515 | * bdi_add_default_flusher_task() occured, further additions will block |
| 516 | * waiting for previous additions to finish. |
| 517 | */ |
| 518 | if (!test_and_set_bit(BDI_pending, &bdi->state)) { |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 519 | list_del_rcu(&bdi->bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 520 | |
| 521 | /* |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 522 | * We must wait for the current RCU period to end before |
| 523 | * moving to the pending list. So schedule that operation |
| 524 | * from an RCU callback. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 525 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 526 | call_rcu(&bdi->rcu_head, bdi_add_to_pending); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 527 | } |
| 528 | } |
| 529 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 530 | /* |
| 531 | * Remove bdi from bdi_list, and ensure that it is no longer visible |
| 532 | */ |
| 533 | static void bdi_remove_from_list(struct backing_dev_info *bdi) |
| 534 | { |
| 535 | spin_lock_bh(&bdi_lock); |
| 536 | list_del_rcu(&bdi->bdi_list); |
| 537 | spin_unlock_bh(&bdi_lock); |
| 538 | |
| 539 | synchronize_rcu(); |
| 540 | } |
| 541 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 542 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| 543 | const char *fmt, ...) |
| 544 | { |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 545 | va_list args; |
| 546 | int ret = 0; |
| 547 | struct device *dev; |
| 548 | |
Andrew Morton | 69fc208 | 2008-12-09 13:14:06 -0800 | [diff] [blame] | 549 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
Kay Sievers | f1d0b06 | 2008-12-02 10:31:50 -0800 | [diff] [blame] | 550 | goto exit; |
| 551 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 552 | va_start(args, fmt); |
Greg Kroah-Hartman | 19051c5 | 2008-05-15 13:44:08 -0700 | [diff] [blame] | 553 | dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 554 | va_end(args); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 555 | if (IS_ERR(dev)) { |
| 556 | ret = PTR_ERR(dev); |
| 557 | goto exit; |
| 558 | } |
| 559 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 560 | spin_lock_bh(&bdi_lock); |
| 561 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
| 562 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 563 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 564 | bdi->dev = dev; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 565 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 566 | /* |
| 567 | * Just start the forker thread for our default backing_dev_info, |
| 568 | * and add other bdi's to the list. They will get a thread created |
| 569 | * on-demand when they need it. |
| 570 | */ |
| 571 | if (bdi_cap_flush_forker(bdi)) { |
| 572 | struct bdi_writeback *wb = &bdi->wb; |
| 573 | |
| 574 | wb->task = kthread_run(bdi_forker_task, wb, "bdi-%s", |
| 575 | dev_name(dev)); |
| 576 | if (IS_ERR(wb->task)) { |
| 577 | wb->task = NULL; |
| 578 | ret = -ENOMEM; |
| 579 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 580 | bdi_remove_from_list(bdi); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 581 | goto exit; |
| 582 | } |
| 583 | } |
| 584 | |
| 585 | bdi_debug_register(bdi, dev_name(dev)); |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 586 | set_bit(BDI_registered, &bdi->state); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 587 | exit: |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 588 | return ret; |
| 589 | } |
| 590 | EXPORT_SYMBOL(bdi_register); |
| 591 | |
| 592 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) |
| 593 | { |
| 594 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); |
| 595 | } |
| 596 | EXPORT_SYMBOL(bdi_register_dev); |
| 597 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 598 | /* |
| 599 | * Remove bdi from the global list and shutdown any threads we have running |
| 600 | */ |
| 601 | static void bdi_wb_shutdown(struct backing_dev_info *bdi) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 602 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 603 | struct bdi_writeback *wb; |
| 604 | |
| 605 | if (!bdi_cap_writeback_dirty(bdi)) |
| 606 | return; |
| 607 | |
| 608 | /* |
| 609 | * If setup is pending, wait for that to complete first |
| 610 | */ |
| 611 | wait_on_bit(&bdi->state, BDI_pending, bdi_sched_wait, |
| 612 | TASK_UNINTERRUPTIBLE); |
| 613 | |
| 614 | /* |
| 615 | * Make sure nobody finds us on the bdi_list anymore |
| 616 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 617 | bdi_remove_from_list(bdi); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 618 | |
| 619 | /* |
| 620 | * Finally, kill the kernel threads. We don't need to be RCU |
Romit Dasgupta | c62b17a | 2009-11-12 13:08:11 +0100 | [diff] [blame] | 621 | * safe anymore, since the bdi is gone from visibility. Force |
| 622 | * unfreeze of the thread before calling kthread_stop(), otherwise |
| 623 | * it would never exet if it is currently stuck in the refrigerator. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 624 | */ |
Romit Dasgupta | c62b17a | 2009-11-12 13:08:11 +0100 | [diff] [blame] | 625 | list_for_each_entry(wb, &bdi->wb_list, list) { |
OGAWA Hirofumi | bf7ec5b | 2009-12-03 13:49:43 +0100 | [diff] [blame] | 626 | thaw_process(wb->task); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 627 | kthread_stop(wb->task); |
Romit Dasgupta | c62b17a | 2009-11-12 13:08:11 +0100 | [diff] [blame] | 628 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 629 | } |
| 630 | |
Jens Axboe | 592b09a | 2009-10-29 11:46:12 +0100 | [diff] [blame] | 631 | /* |
| 632 | * This bdi is going away now, make sure that no super_blocks point to it |
| 633 | */ |
| 634 | static void bdi_prune_sb(struct backing_dev_info *bdi) |
| 635 | { |
| 636 | struct super_block *sb; |
| 637 | |
| 638 | spin_lock(&sb_lock); |
| 639 | list_for_each_entry(sb, &super_blocks, s_list) { |
| 640 | if (sb->s_bdi == bdi) |
| 641 | sb->s_bdi = NULL; |
| 642 | } |
| 643 | spin_unlock(&sb_lock); |
| 644 | } |
| 645 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 646 | void bdi_unregister(struct backing_dev_info *bdi) |
| 647 | { |
| 648 | if (bdi->dev) { |
Jens Axboe | 8c4db33 | 2009-11-03 20:18:44 +0100 | [diff] [blame] | 649 | bdi_prune_sb(bdi); |
| 650 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 651 | if (!bdi_cap_flush_forker(bdi)) |
| 652 | bdi_wb_shutdown(bdi); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 653 | bdi_debug_unregister(bdi); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 654 | device_unregister(bdi->dev); |
| 655 | bdi->dev = NULL; |
| 656 | } |
| 657 | } |
| 658 | EXPORT_SYMBOL(bdi_unregister); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 659 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 660 | int bdi_init(struct backing_dev_info *bdi) |
| 661 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 662 | int i, err; |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 663 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 664 | bdi->dev = NULL; |
| 665 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 666 | bdi->min_ratio = 0; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 667 | bdi->max_ratio = 100; |
| 668 | bdi->max_prop_frac = PROP_FRAC_BASE; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 669 | spin_lock_init(&bdi->wb_lock); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 670 | INIT_RCU_HEAD(&bdi->rcu_head); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 671 | INIT_LIST_HEAD(&bdi->bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 672 | INIT_LIST_HEAD(&bdi->wb_list); |
| 673 | INIT_LIST_HEAD(&bdi->work_list); |
| 674 | |
| 675 | bdi_wb_init(&bdi->wb, bdi); |
| 676 | |
| 677 | /* |
| 678 | * Just one thread support for now, hard code mask and count |
| 679 | */ |
| 680 | bdi->wb_mask = 1; |
| 681 | bdi->wb_cnt = 1; |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 682 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 683 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
Peter Zijlstra | ea31951 | 2008-12-26 15:08:55 +0100 | [diff] [blame] | 684 | err = percpu_counter_init(&bdi->bdi_stat[i], 0); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 685 | if (err) |
| 686 | goto err; |
| 687 | } |
| 688 | |
| 689 | bdi->dirty_exceeded = 0; |
| 690 | err = prop_local_init_percpu(&bdi->completions); |
| 691 | |
| 692 | if (err) { |
| 693 | err: |
Denis Cheng | 4b01a0b | 2007-12-04 23:45:07 -0800 | [diff] [blame] | 694 | while (i--) |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 695 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 696 | } |
| 697 | |
| 698 | return err; |
| 699 | } |
| 700 | EXPORT_SYMBOL(bdi_init); |
| 701 | |
| 702 | void bdi_destroy(struct backing_dev_info *bdi) |
| 703 | { |
| 704 | int i; |
| 705 | |
Jens Axboe | ce5f8e7 | 2009-09-14 12:57:56 +0200 | [diff] [blame] | 706 | /* |
| 707 | * Splice our entries to the default_backing_dev_info, if this |
| 708 | * bdi disappears |
| 709 | */ |
| 710 | if (bdi_has_dirty_io(bdi)) { |
| 711 | struct bdi_writeback *dst = &default_backing_dev_info.wb; |
| 712 | |
| 713 | spin_lock(&inode_lock); |
| 714 | list_splice(&bdi->wb.b_dirty, &dst->b_dirty); |
| 715 | list_splice(&bdi->wb.b_io, &dst->b_io); |
| 716 | list_splice(&bdi->wb.b_more_io, &dst->b_more_io); |
| 717 | spin_unlock(&inode_lock); |
| 718 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 719 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 720 | bdi_unregister(bdi); |
| 721 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 722 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
| 723 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 724 | |
| 725 | prop_local_destroy_percpu(&bdi->completions); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 726 | } |
| 727 | EXPORT_SYMBOL(bdi_destroy); |
| 728 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 729 | /* |
| 730 | * For use from filesystems to quickly init and register a bdi associated |
| 731 | * with dirty writeback |
| 732 | */ |
| 733 | int bdi_setup_and_register(struct backing_dev_info *bdi, char *name, |
| 734 | unsigned int cap) |
| 735 | { |
| 736 | char tmp[32]; |
| 737 | int err; |
| 738 | |
| 739 | bdi->name = name; |
| 740 | bdi->capabilities = cap; |
| 741 | err = bdi_init(bdi); |
| 742 | if (err) |
| 743 | return err; |
| 744 | |
| 745 | sprintf(tmp, "%.28s%s", name, "-%d"); |
| 746 | err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq)); |
| 747 | if (err) { |
| 748 | bdi_destroy(bdi); |
| 749 | return err; |
| 750 | } |
| 751 | |
| 752 | return 0; |
| 753 | } |
| 754 | EXPORT_SYMBOL(bdi_setup_and_register); |
| 755 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 756 | static wait_queue_head_t congestion_wqh[2] = { |
| 757 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), |
| 758 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) |
| 759 | }; |
| 760 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 761 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 762 | { |
| 763 | enum bdi_state bit; |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 764 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 765 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 766 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 767 | clear_bit(bit, &bdi->state); |
| 768 | smp_mb__after_clear_bit(); |
| 769 | if (waitqueue_active(wqh)) |
| 770 | wake_up(wqh); |
| 771 | } |
| 772 | EXPORT_SYMBOL(clear_bdi_congested); |
| 773 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 774 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 775 | { |
| 776 | enum bdi_state bit; |
| 777 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 778 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 779 | set_bit(bit, &bdi->state); |
| 780 | } |
| 781 | EXPORT_SYMBOL(set_bdi_congested); |
| 782 | |
| 783 | /** |
| 784 | * congestion_wait - wait for a backing_dev to become uncongested |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 785 | * @sync: SYNC or ASYNC IO |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 786 | * @timeout: timeout in jiffies |
| 787 | * |
| 788 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit |
| 789 | * write congestion. If no backing_devs are congested then just wait for the |
| 790 | * next write to be completed. |
| 791 | */ |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 792 | long congestion_wait(int sync, long timeout) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 793 | { |
| 794 | long ret; |
| 795 | DEFINE_WAIT(wait); |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 796 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 797 | |
| 798 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 799 | ret = io_schedule_timeout(timeout); |
| 800 | finish_wait(wqh, &wait); |
| 801 | return ret; |
| 802 | } |
| 803 | EXPORT_SYMBOL(congestion_wait); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 804 | |