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> |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 13 | #include <linux/slab.h> |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 14 | #include <trace/events/writeback.h> |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 15 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 16 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
| 17 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 18 | struct backing_dev_info default_backing_dev_info = { |
Jens Axboe | d993831 | 2009-06-12 14:45:52 +0200 | [diff] [blame] | 19 | .name = "default", |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 20 | .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE, |
| 21 | .state = 0, |
| 22 | .capabilities = BDI_CAP_MAP_COPY, |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 23 | }; |
| 24 | EXPORT_SYMBOL_GPL(default_backing_dev_info); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 25 | |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 26 | struct backing_dev_info noop_backing_dev_info = { |
| 27 | .name = "noop", |
Jan Kara | 976e48f | 2010-09-21 11:48:55 +0200 | [diff] [blame] | 28 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 29 | }; |
| 30 | EXPORT_SYMBOL_GPL(noop_backing_dev_info); |
| 31 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 32 | static struct class *bdi_class; |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 33 | |
| 34 | /* |
| 35 | * bdi_lock protects updates to bdi_list and bdi_pending_list, as well as |
| 36 | * reader side protection for bdi_pending_list. bdi_list has RCU reader side |
| 37 | * locking. |
| 38 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 39 | DEFINE_SPINLOCK(bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 40 | LIST_HEAD(bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 41 | LIST_HEAD(bdi_pending_list); |
| 42 | |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 43 | void bdi_lock_two(struct bdi_writeback *wb1, struct bdi_writeback *wb2) |
| 44 | { |
| 45 | if (wb1 < wb2) { |
| 46 | spin_lock(&wb1->list_lock); |
| 47 | spin_lock_nested(&wb2->list_lock, 1); |
| 48 | } else { |
| 49 | spin_lock(&wb2->list_lock); |
| 50 | spin_lock_nested(&wb1->list_lock, 1); |
| 51 | } |
| 52 | } |
| 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; |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 68 | struct bdi_writeback *wb = &bdi->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; |
Gustavo F. Padovan | 345227d | 2011-05-20 21:23:37 +0200 | [diff] [blame] | 72 | unsigned long nr_dirty, nr_io, nr_more_io; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 73 | struct inode *inode; |
| 74 | |
Gustavo F. Padovan | 345227d | 2011-05-20 21:23:37 +0200 | [diff] [blame] | 75 | nr_dirty = nr_io = nr_more_io = 0; |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 76 | spin_lock(&wb->list_lock); |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 77 | list_for_each_entry(inode, &wb->b_dirty, i_wb_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 78 | nr_dirty++; |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 79 | list_for_each_entry(inode, &wb->b_io, i_wb_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 80 | nr_io++; |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 81 | list_for_each_entry(inode, &wb->b_more_io, i_wb_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 82 | nr_more_io++; |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 83 | spin_unlock(&wb->list_lock); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 84 | |
Wu Fengguang | 16c4042 | 2010-08-11 14:17:39 -0700 | [diff] [blame] | 85 | global_dirty_limits(&background_thresh, &dirty_thresh); |
| 86 | bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 87 | |
| 88 | #define K(x) ((x) << (PAGE_SHIFT - 10)) |
| 89 | seq_printf(m, |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 90 | "BdiWriteback: %10lu kB\n" |
| 91 | "BdiReclaimable: %10lu kB\n" |
| 92 | "BdiDirtyThresh: %10lu kB\n" |
| 93 | "DirtyThresh: %10lu kB\n" |
| 94 | "BackgroundThresh: %10lu kB\n" |
Wu Fengguang | c8e28ce | 2011-01-23 10:07:47 -0600 | [diff] [blame] | 95 | "BdiDirtied: %10lu kB\n" |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 96 | "BdiWritten: %10lu kB\n" |
| 97 | "BdiWriteBandwidth: %10lu kBps\n" |
| 98 | "b_dirty: %10lu\n" |
| 99 | "b_io: %10lu\n" |
| 100 | "b_more_io: %10lu\n" |
| 101 | "bdi_list: %10u\n" |
| 102 | "state: %10lx\n", |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 103 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), |
| 104 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 105 | K(bdi_thresh), |
| 106 | K(dirty_thresh), |
| 107 | K(background_thresh), |
Wu Fengguang | c8e28ce | 2011-01-23 10:07:47 -0600 | [diff] [blame] | 108 | (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 109 | (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)), |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 110 | (unsigned long) K(bdi->write_bandwidth), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 111 | nr_dirty, |
| 112 | nr_io, |
| 113 | nr_more_io, |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 114 | !list_empty(&bdi->bdi_list), bdi->state); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 115 | #undef K |
| 116 | |
| 117 | return 0; |
| 118 | } |
| 119 | |
| 120 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) |
| 121 | { |
| 122 | return single_open(file, bdi_debug_stats_show, inode->i_private); |
| 123 | } |
| 124 | |
| 125 | static const struct file_operations bdi_debug_stats_fops = { |
| 126 | .open = bdi_debug_stats_open, |
| 127 | .read = seq_read, |
| 128 | .llseek = seq_lseek, |
| 129 | .release = single_release, |
| 130 | }; |
| 131 | |
| 132 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) |
| 133 | { |
| 134 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); |
| 135 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, |
| 136 | bdi, &bdi_debug_stats_fops); |
| 137 | } |
| 138 | |
| 139 | static void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 140 | { |
| 141 | debugfs_remove(bdi->debug_stats); |
| 142 | debugfs_remove(bdi->debug_dir); |
| 143 | } |
| 144 | #else |
| 145 | static inline void bdi_debug_init(void) |
| 146 | { |
| 147 | } |
| 148 | static inline void bdi_debug_register(struct backing_dev_info *bdi, |
| 149 | const char *name) |
| 150 | { |
| 151 | } |
| 152 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 153 | { |
| 154 | } |
| 155 | #endif |
| 156 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 157 | static ssize_t read_ahead_kb_store(struct device *dev, |
| 158 | struct device_attribute *attr, |
| 159 | const char *buf, size_t count) |
| 160 | { |
| 161 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 162 | unsigned long read_ahead_kb; |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 163 | ssize_t ret; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 164 | |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 165 | ret = kstrtoul(buf, 10, &read_ahead_kb); |
| 166 | if (ret < 0) |
| 167 | return ret; |
| 168 | |
| 169 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); |
| 170 | |
| 171 | return count; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 172 | } |
| 173 | |
| 174 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) |
| 175 | |
| 176 | #define BDI_SHOW(name, expr) \ |
| 177 | static ssize_t name##_show(struct device *dev, \ |
| 178 | struct device_attribute *attr, char *page) \ |
| 179 | { \ |
| 180 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ |
| 181 | \ |
| 182 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ |
| 183 | } |
| 184 | |
| 185 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) |
| 186 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 187 | static ssize_t min_ratio_store(struct device *dev, |
| 188 | struct device_attribute *attr, const char *buf, size_t count) |
| 189 | { |
| 190 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 191 | unsigned int ratio; |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 192 | ssize_t ret; |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 193 | |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 194 | ret = kstrtouint(buf, 10, &ratio); |
| 195 | if (ret < 0) |
| 196 | return ret; |
| 197 | |
| 198 | ret = bdi_set_min_ratio(bdi, ratio); |
| 199 | if (!ret) |
| 200 | ret = count; |
| 201 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 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); |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 210 | unsigned int ratio; |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 211 | ssize_t ret; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 212 | |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 213 | ret = kstrtouint(buf, 10, &ratio); |
| 214 | if (ret < 0) |
| 215 | return ret; |
| 216 | |
| 217 | ret = bdi_set_max_ratio(bdi, ratio); |
| 218 | if (!ret) |
| 219 | ret = count; |
| 220 | |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 221 | return ret; |
| 222 | } |
| 223 | BDI_SHOW(max_ratio, bdi->max_ratio) |
| 224 | |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 225 | static ssize_t cpu_list_store(struct device *dev, |
| 226 | struct device_attribute *attr, const char *buf, size_t count) |
| 227 | { |
| 228 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 229 | struct bdi_writeback *wb = &bdi->wb; |
| 230 | cpumask_var_t newmask; |
| 231 | ssize_t ret; |
| 232 | struct task_struct *task; |
| 233 | |
| 234 | if (!alloc_cpumask_var(&newmask, GFP_KERNEL)) |
| 235 | return -ENOMEM; |
| 236 | |
| 237 | ret = cpulist_parse(buf, newmask); |
| 238 | if (!ret) { |
| 239 | spin_lock_bh(&bdi->wb_lock); |
| 240 | task = wb->task; |
| 241 | if (task) |
| 242 | get_task_struct(task); |
| 243 | spin_unlock_bh(&bdi->wb_lock); |
| 244 | |
| 245 | mutex_lock(&bdi->flusher_cpumask_lock); |
| 246 | if (task) { |
| 247 | ret = set_cpus_allowed_ptr(task, newmask); |
| 248 | put_task_struct(task); |
| 249 | } |
| 250 | if (ret == 0) { |
| 251 | cpumask_copy(bdi->flusher_cpumask, newmask); |
| 252 | ret = count; |
| 253 | } |
| 254 | mutex_unlock(&bdi->flusher_cpumask_lock); |
| 255 | |
| 256 | } |
| 257 | free_cpumask_var(newmask); |
| 258 | |
| 259 | return ret; |
| 260 | } |
| 261 | |
| 262 | static ssize_t cpu_list_show(struct device *dev, |
| 263 | struct device_attribute *attr, char *page) |
| 264 | { |
| 265 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 266 | ssize_t ret; |
| 267 | |
| 268 | mutex_lock(&bdi->flusher_cpumask_lock); |
| 269 | ret = cpulist_scnprintf(page, PAGE_SIZE-1, bdi->flusher_cpumask); |
| 270 | mutex_unlock(&bdi->flusher_cpumask_lock); |
| 271 | |
| 272 | return ret; |
| 273 | } |
| 274 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 275 | #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) |
| 276 | |
| 277 | static struct device_attribute bdi_dev_attrs[] = { |
| 278 | __ATTR_RW(read_ahead_kb), |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 279 | __ATTR_RW(min_ratio), |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 280 | __ATTR_RW(max_ratio), |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 281 | __ATTR_RW(cpu_list), |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 282 | __ATTR_NULL, |
| 283 | }; |
| 284 | |
| 285 | static __init int bdi_class_init(void) |
| 286 | { |
| 287 | bdi_class = class_create(THIS_MODULE, "bdi"); |
Anton Blanchard | 1442145 | 2010-04-02 09:46:55 +0200 | [diff] [blame] | 288 | if (IS_ERR(bdi_class)) |
| 289 | return PTR_ERR(bdi_class); |
| 290 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 291 | bdi_class->dev_attrs = bdi_dev_attrs; |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 292 | bdi_debug_init(); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 293 | return 0; |
| 294 | } |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 295 | postcore_initcall(bdi_class_init); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 296 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 297 | static int __init default_bdi_init(void) |
| 298 | { |
| 299 | int err; |
| 300 | |
| 301 | err = bdi_init(&default_backing_dev_info); |
| 302 | if (!err) |
| 303 | bdi_register(&default_backing_dev_info, NULL, "default"); |
Jan Kara | 976e48f | 2010-09-21 11:48:55 +0200 | [diff] [blame] | 304 | err = bdi_init(&noop_backing_dev_info); |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 305 | |
| 306 | return err; |
| 307 | } |
| 308 | subsys_initcall(default_bdi_init); |
| 309 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 310 | int bdi_has_dirty_io(struct backing_dev_info *bdi) |
| 311 | { |
| 312 | return wb_has_dirty_io(&bdi->wb); |
| 313 | } |
| 314 | |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 315 | static void wakeup_timer_fn(unsigned long data) |
| 316 | { |
| 317 | struct backing_dev_info *bdi = (struct backing_dev_info *)data; |
| 318 | |
| 319 | spin_lock_bh(&bdi->wb_lock); |
| 320 | if (bdi->wb.task) { |
Artem Bityutskiy | 6033202 | 2010-07-25 14:29:24 +0300 | [diff] [blame] | 321 | trace_writeback_wake_thread(bdi); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 322 | wake_up_process(bdi->wb.task); |
Rabin Vincent | 2673b4c | 2012-01-29 12:17:33 -0600 | [diff] [blame] | 323 | } else if (bdi->dev) { |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 324 | /* |
| 325 | * When bdi tasks are inactive for long time, they are killed. |
| 326 | * In this case we have to wake-up the forker thread which |
| 327 | * should create and run the bdi thread. |
| 328 | */ |
Artem Bityutskiy | 6033202 | 2010-07-25 14:29:24 +0300 | [diff] [blame] | 329 | trace_writeback_wake_forker_thread(bdi); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 330 | wake_up_process(default_backing_dev_info.wb.task); |
| 331 | } |
| 332 | spin_unlock_bh(&bdi->wb_lock); |
| 333 | } |
| 334 | |
| 335 | /* |
| 336 | * This function is used when the first inode for this bdi is marked dirty. It |
| 337 | * wakes-up the corresponding bdi thread which should then take care of the |
| 338 | * periodic background write-out of dirty inodes. Since the write-out would |
| 339 | * starts only 'dirty_writeback_interval' centisecs from now anyway, we just |
| 340 | * set up a timer which wakes the bdi thread up later. |
| 341 | * |
| 342 | * Note, we wouldn't bother setting up the timer, but this function is on the |
| 343 | * fast-path (used by '__mark_inode_dirty()'), so we save few context switches |
| 344 | * by delaying the wake-up. |
| 345 | */ |
| 346 | void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi) |
| 347 | { |
| 348 | unsigned long timeout; |
| 349 | |
| 350 | timeout = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 351 | mod_timer(&bdi->wb.wakeup_timer, jiffies + timeout); |
| 352 | } |
| 353 | |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 354 | /* |
| 355 | * Calculate the longest interval (jiffies) bdi threads are allowed to be |
| 356 | * inactive. |
| 357 | */ |
| 358 | static unsigned long bdi_longest_inactive(void) |
| 359 | { |
| 360 | unsigned long interval; |
| 361 | |
| 362 | interval = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 363 | return max(5UL * 60 * HZ, interval); |
| 364 | } |
| 365 | |
Jan Kara | 5a042aa | 2011-09-02 17:04:09 -0600 | [diff] [blame] | 366 | /* |
| 367 | * Clear pending bit and wakeup anybody waiting for flusher thread creation or |
| 368 | * shutdown |
| 369 | */ |
| 370 | static void bdi_clear_pending(struct backing_dev_info *bdi) |
| 371 | { |
| 372 | clear_bit(BDI_pending, &bdi->state); |
| 373 | smp_mb__after_clear_bit(); |
| 374 | wake_up_bit(&bdi->state, BDI_pending); |
| 375 | } |
| 376 | |
Artem Bityutskiy | 6f904ff | 2010-07-25 14:29:11 +0300 | [diff] [blame] | 377 | static int bdi_forker_thread(void *ptr) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 378 | { |
| 379 | struct bdi_writeback *me = ptr; |
| 380 | |
Peter Zijlstra | 766f916 | 2010-10-26 14:22:45 -0700 | [diff] [blame] | 381 | current->flags |= PF_SWAPWRITE; |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 382 | set_freezable(); |
| 383 | |
| 384 | /* |
| 385 | * Our parent may run at a different priority, just set us to normal |
| 386 | */ |
| 387 | set_user_nice(current, 0); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 388 | |
| 389 | for (;;) { |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 390 | struct task_struct *task = NULL; |
Artem Bityutskiy | 78c40cb | 2010-07-25 14:29:17 +0300 | [diff] [blame] | 391 | struct backing_dev_info *bdi; |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 392 | enum { |
| 393 | NO_ACTION, /* Nothing to do */ |
| 394 | FORK_THREAD, /* Fork bdi thread */ |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 395 | KILL_THREAD, /* Kill inactive bdi thread */ |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 396 | } action = NO_ACTION; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 397 | |
| 398 | /* |
| 399 | * Temporary measure, we want to make sure we don't see |
| 400 | * dirty data on the default backing_dev_info |
| 401 | */ |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 402 | if (wb_has_dirty_io(me) || !list_empty(&me->bdi->work_list)) { |
| 403 | del_timer(&me->wakeup_timer); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 404 | wb_do_writeback(me, 0); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 405 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 406 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 407 | spin_lock_bh(&bdi_lock); |
Jan Kara | 09f40f9 | 2011-09-02 17:04:10 -0600 | [diff] [blame] | 408 | /* |
| 409 | * In the following loop we are going to check whether we have |
| 410 | * some work to do without any synchronization with tasks |
Andrew Morton | 20c8c62 | 2011-10-31 17:08:54 -0700 | [diff] [blame] | 411 | * waking us up to do work for them. Set the task state here |
| 412 | * so that we don't miss wakeups after verifying conditions. |
Jan Kara | 09f40f9 | 2011-09-02 17:04:10 -0600 | [diff] [blame] | 413 | */ |
Artem Bityutskiy | c5f7ad2 | 2010-07-25 14:29:13 +0300 | [diff] [blame] | 414 | set_current_state(TASK_INTERRUPTIBLE); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 415 | |
Artem Bityutskiy | 78c40cb | 2010-07-25 14:29:17 +0300 | [diff] [blame] | 416 | list_for_each_entry(bdi, &bdi_list, bdi_list) { |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 417 | bool have_dirty_io; |
| 418 | |
| 419 | if (!bdi_cap_writeback_dirty(bdi) || |
| 420 | bdi_cap_flush_forker(bdi)) |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 421 | continue; |
| 422 | |
Artem Bityutskiy | 080dcec | 2010-07-25 14:29:16 +0300 | [diff] [blame] | 423 | WARN(!test_bit(BDI_registered, &bdi->state), |
| 424 | "bdi %p/%s is not registered!\n", bdi, bdi->name); |
| 425 | |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 426 | have_dirty_io = !list_empty(&bdi->work_list) || |
| 427 | wb_has_dirty_io(&bdi->wb); |
Artem Bityutskiy | 78c40cb | 2010-07-25 14:29:17 +0300 | [diff] [blame] | 428 | |
| 429 | /* |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 430 | * If the bdi has work to do, but the thread does not |
| 431 | * exist - create it. |
Artem Bityutskiy | 78c40cb | 2010-07-25 14:29:17 +0300 | [diff] [blame] | 432 | */ |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 433 | if (!bdi->wb.task && have_dirty_io) { |
| 434 | /* |
| 435 | * Set the pending bit - if someone will try to |
| 436 | * unregister this bdi - it'll wait on this bit. |
| 437 | */ |
| 438 | set_bit(BDI_pending, &bdi->state); |
| 439 | action = FORK_THREAD; |
| 440 | break; |
| 441 | } |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 442 | |
Jens Axboe | 6bf05d0 | 2010-08-04 13:34:31 +0200 | [diff] [blame] | 443 | spin_lock(&bdi->wb_lock); |
| 444 | |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 445 | /* |
| 446 | * If there is no work to do and the bdi thread was |
| 447 | * inactive long enough - kill it. The wb_lock is taken |
| 448 | * to make sure no-one adds more work to this bdi and |
| 449 | * wakes the bdi thread up. |
| 450 | */ |
| 451 | if (bdi->wb.task && !have_dirty_io && |
| 452 | time_after(jiffies, bdi->wb.last_active + |
| 453 | bdi_longest_inactive())) { |
| 454 | task = bdi->wb.task; |
| 455 | bdi->wb.task = NULL; |
| 456 | spin_unlock(&bdi->wb_lock); |
| 457 | set_bit(BDI_pending, &bdi->state); |
| 458 | action = KILL_THREAD; |
| 459 | break; |
| 460 | } |
Jens Axboe | 6bf05d0 | 2010-08-04 13:34:31 +0200 | [diff] [blame] | 461 | spin_unlock(&bdi->wb_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 462 | } |
Artem Bityutskiy | 080dcec | 2010-07-25 14:29:16 +0300 | [diff] [blame] | 463 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 464 | |
Artem Bityutskiy | c4ec790 | 2010-07-25 14:29:14 +0300 | [diff] [blame] | 465 | /* Keep working if default bdi still has things to do */ |
| 466 | if (!list_empty(&me->bdi->work_list)) |
| 467 | __set_current_state(TASK_RUNNING); |
| 468 | |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 469 | switch (action) { |
| 470 | case FORK_THREAD: |
| 471 | __set_current_state(TASK_RUNNING); |
Artem Bityutskiy | 6628bc7 | 2010-08-27 09:15:09 +0200 | [diff] [blame] | 472 | task = kthread_create(bdi_writeback_thread, &bdi->wb, |
| 473 | "flush-%s", dev_name(bdi->dev)); |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 474 | if (IS_ERR(task)) { |
| 475 | /* |
| 476 | * If thread creation fails, force writeout of |
Wu Fengguang | d46db3d | 2011-05-04 19:54:37 -0600 | [diff] [blame] | 477 | * the bdi from the thread. Hopefully 1024 is |
| 478 | * large enough for efficient IO. |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 479 | */ |
Curt Wohlgemuth | 0e175a1 | 2011-10-07 21:54:10 -0600 | [diff] [blame] | 480 | writeback_inodes_wb(&bdi->wb, 1024, |
| 481 | WB_REASON_FORKER_THREAD); |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 482 | } else { |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 483 | int ret; |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 484 | /* |
| 485 | * The spinlock makes sure we do not lose |
| 486 | * wake-ups when racing with 'bdi_queue_work()'. |
Artem Bityutskiy | 6628bc7 | 2010-08-27 09:15:09 +0200 | [diff] [blame] | 487 | * And as soon as the bdi thread is visible, we |
| 488 | * can start it. |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 489 | */ |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 490 | spin_lock_bh(&bdi->wb_lock); |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 491 | bdi->wb.task = task; |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 492 | spin_unlock_bh(&bdi->wb_lock); |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 493 | mutex_lock(&bdi->flusher_cpumask_lock); |
| 494 | ret = set_cpus_allowed_ptr(task, |
| 495 | bdi->flusher_cpumask); |
| 496 | mutex_unlock(&bdi->flusher_cpumask_lock); |
| 497 | if (ret) |
| 498 | printk_once("%s: failed to bind flusher" |
| 499 | " thread %s, error %d\n", |
| 500 | __func__, task->comm, ret); |
Artem Bityutskiy | 6628bc7 | 2010-08-27 09:15:09 +0200 | [diff] [blame] | 501 | wake_up_process(task); |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 502 | } |
Jan Kara | 5a042aa | 2011-09-02 17:04:09 -0600 | [diff] [blame] | 503 | bdi_clear_pending(bdi); |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 504 | break; |
| 505 | |
| 506 | case KILL_THREAD: |
| 507 | __set_current_state(TASK_RUNNING); |
| 508 | kthread_stop(task); |
Jan Kara | 5a042aa | 2011-09-02 17:04:09 -0600 | [diff] [blame] | 509 | bdi_clear_pending(bdi); |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 510 | break; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 511 | |
Artem Bityutskiy | adf3924 | 2010-07-25 14:29:19 +0300 | [diff] [blame] | 512 | case NO_ACTION: |
Artem Bityutskiy | 253c34e | 2010-07-25 14:29:21 +0300 | [diff] [blame] | 513 | if (!wb_has_dirty_io(me) || !dirty_writeback_interval) |
| 514 | /* |
| 515 | * There are no dirty data. The only thing we |
| 516 | * should now care about is checking for |
| 517 | * inactive bdi threads and killing them. Thus, |
| 518 | * let's sleep for longer time, save energy and |
| 519 | * be friendly for battery-driven devices. |
| 520 | */ |
| 521 | schedule_timeout(bdi_longest_inactive()); |
Jens Axboe | 6423104 | 2010-05-21 20:00:35 +0200 | [diff] [blame] | 522 | else |
Artem Bityutskiy | 253c34e | 2010-07-25 14:29:21 +0300 | [diff] [blame] | 523 | schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10)); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 524 | try_to_freeze(); |
Jan Kara | 5a042aa | 2011-09-02 17:04:09 -0600 | [diff] [blame] | 525 | break; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 526 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 527 | } |
| 528 | |
| 529 | return 0; |
| 530 | } |
| 531 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 532 | /* |
| 533 | * Remove bdi from bdi_list, and ensure that it is no longer visible |
| 534 | */ |
| 535 | static void bdi_remove_from_list(struct backing_dev_info *bdi) |
| 536 | { |
| 537 | spin_lock_bh(&bdi_lock); |
| 538 | list_del_rcu(&bdi->bdi_list); |
| 539 | spin_unlock_bh(&bdi_lock); |
| 540 | |
Mikulas Patocka | ef32308 | 2011-07-23 20:44:24 +0200 | [diff] [blame] | 541 | synchronize_rcu_expedited(); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 542 | } |
| 543 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 544 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| 545 | const char *fmt, ...) |
| 546 | { |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 547 | va_list args; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 548 | struct device *dev; |
| 549 | |
Andrew Morton | 69fc208 | 2008-12-09 13:14:06 -0800 | [diff] [blame] | 550 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 551 | return 0; |
Kay Sievers | f1d0b06 | 2008-12-02 10:31:50 -0800 | [diff] [blame] | 552 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 553 | va_start(args, fmt); |
Greg Kroah-Hartman | 19051c5 | 2008-05-15 13:44:08 -0700 | [diff] [blame] | 554 | 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] | 555 | va_end(args); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 556 | if (IS_ERR(dev)) |
| 557 | return PTR_ERR(dev); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 558 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 559 | bdi->dev = dev; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 560 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 561 | /* |
| 562 | * Just start the forker thread for our default backing_dev_info, |
| 563 | * and add other bdi's to the list. They will get a thread created |
| 564 | * on-demand when they need it. |
| 565 | */ |
| 566 | if (bdi_cap_flush_forker(bdi)) { |
| 567 | struct bdi_writeback *wb = &bdi->wb; |
| 568 | |
Artem Bityutskiy | 6f904ff | 2010-07-25 14:29:11 +0300 | [diff] [blame] | 569 | wb->task = kthread_run(bdi_forker_thread, wb, "bdi-%s", |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 570 | dev_name(dev)); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 571 | if (IS_ERR(wb->task)) |
| 572 | return PTR_ERR(wb->task); |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 573 | } else { |
| 574 | int node; |
| 575 | /* |
| 576 | * Set up a default cpumask for the flusher threads that |
| 577 | * includes all cpus on the same numa node as the device. |
| 578 | * The mask may be overridden via sysfs. |
| 579 | */ |
| 580 | node = dev_to_node(bdi->dev); |
| 581 | if (node != NUMA_NO_NODE) |
| 582 | cpumask_copy(bdi->flusher_cpumask, |
| 583 | cpumask_of_node(node)); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 584 | } |
| 585 | |
| 586 | bdi_debug_register(bdi, dev_name(dev)); |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 587 | set_bit(BDI_registered, &bdi->state); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 588 | |
| 589 | spin_lock_bh(&bdi_lock); |
| 590 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
| 591 | spin_unlock_bh(&bdi_lock); |
| 592 | |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 593 | trace_writeback_bdi_register(bdi); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 594 | return 0; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 595 | } |
| 596 | EXPORT_SYMBOL(bdi_register); |
| 597 | |
| 598 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) |
| 599 | { |
| 600 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); |
| 601 | } |
| 602 | EXPORT_SYMBOL(bdi_register_dev); |
| 603 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 604 | /* |
| 605 | * Remove bdi from the global list and shutdown any threads we have running |
| 606 | */ |
| 607 | static void bdi_wb_shutdown(struct backing_dev_info *bdi) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 608 | { |
Rabin Vincent | 2673b4c | 2012-01-29 12:17:33 -0600 | [diff] [blame] | 609 | struct task_struct *task; |
| 610 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 611 | if (!bdi_cap_writeback_dirty(bdi)) |
| 612 | return; |
| 613 | |
| 614 | /* |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 615 | * Make sure nobody finds us on the bdi_list anymore |
| 616 | */ |
| 617 | bdi_remove_from_list(bdi); |
| 618 | |
| 619 | /* |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 620 | * If setup is pending, wait for that to complete first |
| 621 | */ |
| 622 | wait_on_bit(&bdi->state, BDI_pending, bdi_sched_wait, |
| 623 | TASK_UNINTERRUPTIBLE); |
| 624 | |
| 625 | /* |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 626 | * Finally, kill the kernel thread. We don't need to be RCU |
Tejun Heo | 8a32c44 | 2011-11-21 12:32:23 -0800 | [diff] [blame] | 627 | * safe anymore, since the bdi is gone from visibility. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 628 | */ |
Rabin Vincent | 2673b4c | 2012-01-29 12:17:33 -0600 | [diff] [blame] | 629 | spin_lock_bh(&bdi->wb_lock); |
| 630 | task = bdi->wb.task; |
| 631 | bdi->wb.task = NULL; |
| 632 | spin_unlock_bh(&bdi->wb_lock); |
| 633 | |
| 634 | if (task) |
| 635 | kthread_stop(task); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 636 | } |
| 637 | |
Jens Axboe | 592b09a | 2009-10-29 11:46:12 +0100 | [diff] [blame] | 638 | /* |
| 639 | * This bdi is going away now, make sure that no super_blocks point to it |
| 640 | */ |
| 641 | static void bdi_prune_sb(struct backing_dev_info *bdi) |
| 642 | { |
| 643 | struct super_block *sb; |
| 644 | |
| 645 | spin_lock(&sb_lock); |
| 646 | list_for_each_entry(sb, &super_blocks, s_list) { |
| 647 | if (sb->s_bdi == bdi) |
Jens Axboe | 95f2860 | 2011-03-17 11:13:12 +0100 | [diff] [blame] | 648 | sb->s_bdi = &default_backing_dev_info; |
Jens Axboe | 592b09a | 2009-10-29 11:46:12 +0100 | [diff] [blame] | 649 | } |
| 650 | spin_unlock(&sb_lock); |
| 651 | } |
| 652 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 653 | void bdi_unregister(struct backing_dev_info *bdi) |
| 654 | { |
Rabin Vincent | 2673b4c | 2012-01-29 12:17:33 -0600 | [diff] [blame] | 655 | struct device *dev = bdi->dev; |
| 656 | |
| 657 | if (dev) { |
Peter Zijlstra | ccb6108 | 2011-07-25 17:11:57 -0700 | [diff] [blame] | 658 | bdi_set_min_ratio(bdi, 0); |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 659 | trace_writeback_bdi_unregister(bdi); |
Jens Axboe | 8c4db33 | 2009-11-03 20:18:44 +0100 | [diff] [blame] | 660 | bdi_prune_sb(bdi); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 661 | del_timer_sync(&bdi->wb.wakeup_timer); |
Jens Axboe | 8c4db33 | 2009-11-03 20:18:44 +0100 | [diff] [blame] | 662 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 663 | if (!bdi_cap_flush_forker(bdi)) |
| 664 | bdi_wb_shutdown(bdi); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 665 | bdi_debug_unregister(bdi); |
Rabin Vincent | 2673b4c | 2012-01-29 12:17:33 -0600 | [diff] [blame] | 666 | |
| 667 | spin_lock_bh(&bdi->wb_lock); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 668 | bdi->dev = NULL; |
Rabin Vincent | 2673b4c | 2012-01-29 12:17:33 -0600 | [diff] [blame] | 669 | spin_unlock_bh(&bdi->wb_lock); |
| 670 | |
| 671 | device_unregister(dev); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 672 | } |
| 673 | } |
| 674 | EXPORT_SYMBOL(bdi_unregister); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 675 | |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 676 | static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) |
| 677 | { |
| 678 | memset(wb, 0, sizeof(*wb)); |
| 679 | |
| 680 | wb->bdi = bdi; |
| 681 | wb->last_old_flush = jiffies; |
| 682 | INIT_LIST_HEAD(&wb->b_dirty); |
| 683 | INIT_LIST_HEAD(&wb->b_io); |
| 684 | INIT_LIST_HEAD(&wb->b_more_io); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 685 | spin_lock_init(&wb->list_lock); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 686 | setup_timer(&wb->wakeup_timer, wakeup_timer_fn, (unsigned long)bdi); |
| 687 | } |
| 688 | |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 689 | /* |
| 690 | * Initial write bandwidth: 100 MB/s |
| 691 | */ |
| 692 | #define INIT_BW (100 << (20 - PAGE_SHIFT)) |
| 693 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 694 | int bdi_init(struct backing_dev_info *bdi) |
| 695 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 696 | int i, err; |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 697 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 698 | bdi->dev = NULL; |
| 699 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 700 | bdi->min_ratio = 0; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 701 | bdi->max_ratio = 100; |
Jan Kara | eb608e3 | 2012-05-24 18:59:11 +0200 | [diff] [blame] | 702 | bdi->max_prop_frac = FPROP_FRAC_BASE; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 703 | spin_lock_init(&bdi->wb_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 704 | INIT_LIST_HEAD(&bdi->bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 705 | INIT_LIST_HEAD(&bdi->work_list); |
| 706 | |
| 707 | bdi_wb_init(&bdi->wb, bdi); |
| 708 | |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 709 | if (!bdi_cap_flush_forker(bdi)) { |
| 710 | bdi->flusher_cpumask = kmalloc(sizeof(cpumask_t), GFP_KERNEL); |
| 711 | if (!bdi->flusher_cpumask) |
| 712 | return -ENOMEM; |
| 713 | cpumask_setall(bdi->flusher_cpumask); |
| 714 | mutex_init(&bdi->flusher_cpumask_lock); |
| 715 | } else |
| 716 | bdi->flusher_cpumask = NULL; |
| 717 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 718 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
Peter Zijlstra | ea31951 | 2008-12-26 15:08:55 +0100 | [diff] [blame] | 719 | err = percpu_counter_init(&bdi->bdi_stat[i], 0); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 720 | if (err) |
| 721 | goto err; |
| 722 | } |
| 723 | |
| 724 | bdi->dirty_exceeded = 0; |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 725 | |
| 726 | bdi->bw_time_stamp = jiffies; |
| 727 | bdi->written_stamp = 0; |
| 728 | |
Wu Fengguang | 7381131 | 2011-08-26 15:53:24 -0600 | [diff] [blame] | 729 | bdi->balanced_dirty_ratelimit = INIT_BW; |
Wu Fengguang | be3ffa2 | 2011-06-12 10:51:31 -0600 | [diff] [blame] | 730 | bdi->dirty_ratelimit = INIT_BW; |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 731 | bdi->write_bandwidth = INIT_BW; |
| 732 | bdi->avg_write_bandwidth = INIT_BW; |
| 733 | |
Jan Kara | eb608e3 | 2012-05-24 18:59:11 +0200 | [diff] [blame] | 734 | err = fprop_local_init_percpu(&bdi->completions); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 735 | |
| 736 | if (err) { |
| 737 | err: |
Denis Cheng | 4b01a0b | 2007-12-04 23:45:07 -0800 | [diff] [blame] | 738 | while (i--) |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 739 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 740 | kfree(bdi->flusher_cpumask); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 741 | } |
| 742 | |
| 743 | return err; |
| 744 | } |
| 745 | EXPORT_SYMBOL(bdi_init); |
| 746 | |
| 747 | void bdi_destroy(struct backing_dev_info *bdi) |
| 748 | { |
| 749 | int i; |
| 750 | |
Jens Axboe | ce5f8e7 | 2009-09-14 12:57:56 +0200 | [diff] [blame] | 751 | /* |
| 752 | * Splice our entries to the default_backing_dev_info, if this |
| 753 | * bdi disappears |
| 754 | */ |
| 755 | if (bdi_has_dirty_io(bdi)) { |
| 756 | struct bdi_writeback *dst = &default_backing_dev_info.wb; |
| 757 | |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 758 | bdi_lock_two(&bdi->wb, dst); |
Jens Axboe | ce5f8e7 | 2009-09-14 12:57:56 +0200 | [diff] [blame] | 759 | list_splice(&bdi->wb.b_dirty, &dst->b_dirty); |
| 760 | list_splice(&bdi->wb.b_io, &dst->b_io); |
| 761 | list_splice(&bdi->wb.b_more_io, &dst->b_more_io); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 762 | spin_unlock(&bdi->wb.list_lock); |
| 763 | spin_unlock(&dst->list_lock); |
Jens Axboe | ce5f8e7 | 2009-09-14 12:57:56 +0200 | [diff] [blame] | 764 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 765 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 766 | bdi_unregister(bdi); |
| 767 | |
Jeff Moyer | 8fa72d23 | 2012-12-05 20:17:21 +0100 | [diff] [blame] | 768 | kfree(bdi->flusher_cpumask); |
| 769 | |
Rabin Vincent | 7a401a9 | 2011-11-11 13:29:04 +0100 | [diff] [blame] | 770 | /* |
| 771 | * If bdi_unregister() had already been called earlier, the |
| 772 | * wakeup_timer could still be armed because bdi_prune_sb() |
| 773 | * can race with the bdi_wakeup_thread_delayed() calls from |
| 774 | * __mark_inode_dirty(). |
| 775 | */ |
| 776 | del_timer_sync(&bdi->wb.wakeup_timer); |
| 777 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 778 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
| 779 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 780 | |
Jan Kara | eb608e3 | 2012-05-24 18:59:11 +0200 | [diff] [blame] | 781 | fprop_local_destroy_percpu(&bdi->completions); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 782 | } |
| 783 | EXPORT_SYMBOL(bdi_destroy); |
| 784 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 785 | /* |
| 786 | * For use from filesystems to quickly init and register a bdi associated |
| 787 | * with dirty writeback |
| 788 | */ |
| 789 | int bdi_setup_and_register(struct backing_dev_info *bdi, char *name, |
| 790 | unsigned int cap) |
| 791 | { |
| 792 | char tmp[32]; |
| 793 | int err; |
| 794 | |
| 795 | bdi->name = name; |
| 796 | bdi->capabilities = cap; |
| 797 | err = bdi_init(bdi); |
| 798 | if (err) |
| 799 | return err; |
| 800 | |
| 801 | sprintf(tmp, "%.28s%s", name, "-%d"); |
| 802 | err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq)); |
| 803 | if (err) { |
| 804 | bdi_destroy(bdi); |
| 805 | return err; |
| 806 | } |
| 807 | |
| 808 | return 0; |
| 809 | } |
| 810 | EXPORT_SYMBOL(bdi_setup_and_register); |
| 811 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 812 | static wait_queue_head_t congestion_wqh[2] = { |
| 813 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), |
| 814 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) |
| 815 | }; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 816 | static atomic_t nr_bdi_congested[2]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 817 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 818 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 819 | { |
| 820 | enum bdi_state bit; |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 821 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 822 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 823 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 824 | if (test_and_clear_bit(bit, &bdi->state)) |
| 825 | atomic_dec(&nr_bdi_congested[sync]); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 826 | smp_mb__after_clear_bit(); |
| 827 | if (waitqueue_active(wqh)) |
| 828 | wake_up(wqh); |
| 829 | } |
| 830 | EXPORT_SYMBOL(clear_bdi_congested); |
| 831 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 832 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 833 | { |
| 834 | enum bdi_state bit; |
| 835 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 836 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 837 | if (!test_and_set_bit(bit, &bdi->state)) |
| 838 | atomic_inc(&nr_bdi_congested[sync]); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 839 | } |
| 840 | EXPORT_SYMBOL(set_bdi_congested); |
| 841 | |
| 842 | /** |
| 843 | * congestion_wait - wait for a backing_dev to become uncongested |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 844 | * @sync: SYNC or ASYNC IO |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 845 | * @timeout: timeout in jiffies |
| 846 | * |
| 847 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit |
| 848 | * write congestion. If no backing_devs are congested then just wait for the |
| 849 | * next write to be completed. |
| 850 | */ |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 851 | long congestion_wait(int sync, long timeout) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 852 | { |
| 853 | long ret; |
Mel Gorman | 52bb919 | 2010-10-26 14:21:41 -0700 | [diff] [blame] | 854 | unsigned long start = jiffies; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 855 | DEFINE_WAIT(wait); |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 856 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 857 | |
| 858 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 859 | ret = io_schedule_timeout(timeout); |
| 860 | finish_wait(wqh, &wait); |
Mel Gorman | 52bb919 | 2010-10-26 14:21:41 -0700 | [diff] [blame] | 861 | |
| 862 | trace_writeback_congestion_wait(jiffies_to_usecs(timeout), |
| 863 | jiffies_to_usecs(jiffies - start)); |
| 864 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 865 | return ret; |
| 866 | } |
| 867 | EXPORT_SYMBOL(congestion_wait); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 868 | |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 869 | /** |
| 870 | * wait_iff_congested - Conditionally wait for a backing_dev to become uncongested or a zone to complete writes |
| 871 | * @zone: A zone to check if it is heavily congested |
| 872 | * @sync: SYNC or ASYNC IO |
| 873 | * @timeout: timeout in jiffies |
| 874 | * |
| 875 | * In the event of a congested backing_dev (any backing_dev) and the given |
| 876 | * @zone has experienced recent congestion, this waits for up to @timeout |
| 877 | * jiffies for either a BDI to exit congestion of the given @sync queue |
| 878 | * or a write to complete. |
| 879 | * |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 880 | * In the absence of zone congestion, cond_resched() is called to yield |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 881 | * the processor if necessary but otherwise does not sleep. |
| 882 | * |
| 883 | * The return value is 0 if the sleep is for the full timeout. Otherwise, |
| 884 | * it is the number of jiffies that were still remaining when the function |
| 885 | * returned. return_value == timeout implies the function did not sleep. |
| 886 | */ |
| 887 | long wait_iff_congested(struct zone *zone, int sync, long timeout) |
| 888 | { |
| 889 | long ret; |
| 890 | unsigned long start = jiffies; |
| 891 | DEFINE_WAIT(wait); |
| 892 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
| 893 | |
| 894 | /* |
| 895 | * If there is no congestion, or heavy congestion is not being |
| 896 | * encountered in the current zone, yield if necessary instead |
| 897 | * of sleeping on the congestion queue |
| 898 | */ |
| 899 | if (atomic_read(&nr_bdi_congested[sync]) == 0 || |
| 900 | !zone_is_reclaim_congested(zone)) { |
| 901 | cond_resched(); |
| 902 | |
| 903 | /* In case we scheduled, work out time remaining */ |
| 904 | ret = timeout - (jiffies - start); |
| 905 | if (ret < 0) |
| 906 | ret = 0; |
| 907 | |
| 908 | goto out; |
| 909 | } |
| 910 | |
| 911 | /* Sleep until uncongested or a write happens */ |
| 912 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 913 | ret = io_schedule_timeout(timeout); |
| 914 | finish_wait(wqh, &wait); |
| 915 | |
| 916 | out: |
| 917 | trace_writeback_wait_iff_congested(jiffies_to_usecs(timeout), |
| 918 | jiffies_to_usecs(jiffies - start)); |
| 919 | |
| 920 | return ret; |
| 921 | } |
| 922 | EXPORT_SYMBOL(wait_iff_congested); |
Wanpeng Li | 3965c9a | 2012-07-31 16:41:52 -0700 | [diff] [blame] | 923 | |
| 924 | int pdflush_proc_obsolete(struct ctl_table *table, int write, |
| 925 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 926 | { |
| 927 | char kbuf[] = "0\n"; |
| 928 | |
| 929 | if (*ppos) { |
| 930 | *lenp = 0; |
| 931 | return 0; |
| 932 | } |
| 933 | |
| 934 | if (copy_to_user(buffer, kbuf, sizeof(kbuf))) |
| 935 | return -EFAULT; |
| 936 | printk_once(KERN_WARNING "%s exported in /proc is scheduled for removal\n", |
| 937 | table->procname); |
| 938 | |
| 939 | *lenp = 2; |
| 940 | *ppos += *lenp; |
| 941 | return 2; |
| 942 | } |