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> |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 13 | #include <trace/events/writeback.h> |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 14 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 15 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
| 16 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 17 | struct backing_dev_info default_backing_dev_info = { |
Jens Axboe | d993831 | 2009-06-12 14:45:52 +0200 | [diff] [blame] | 18 | .name = "default", |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 19 | .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE, |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 20 | }; |
| 21 | EXPORT_SYMBOL_GPL(default_backing_dev_info); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 22 | |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 23 | struct backing_dev_info noop_backing_dev_info = { |
| 24 | .name = "noop", |
Jan Kara | 976e48f | 2010-09-21 11:48:55 +0200 | [diff] [blame] | 25 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 26 | }; |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 27 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 28 | static struct class *bdi_class; |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 29 | |
| 30 | /* |
Tejun Heo | 181387d | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 31 | * bdi_lock protects updates to bdi_list. bdi_list has RCU reader side |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 32 | * locking. |
| 33 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 34 | DEFINE_SPINLOCK(bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 35 | LIST_HEAD(bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 36 | |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 37 | /* bdi_wq serves all asynchronous writeback tasks */ |
| 38 | struct workqueue_struct *bdi_wq; |
| 39 | |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 40 | #ifdef CONFIG_DEBUG_FS |
| 41 | #include <linux/debugfs.h> |
| 42 | #include <linux/seq_file.h> |
| 43 | |
| 44 | static struct dentry *bdi_debug_root; |
| 45 | |
| 46 | static void bdi_debug_init(void) |
| 47 | { |
| 48 | bdi_debug_root = debugfs_create_dir("bdi", NULL); |
| 49 | } |
| 50 | |
| 51 | static int bdi_debug_stats_show(struct seq_file *m, void *v) |
| 52 | { |
| 53 | struct backing_dev_info *bdi = m->private; |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 54 | struct bdi_writeback *wb = &bdi->wb; |
David Rientjes | 364aeb2 | 2009-01-06 14:39:29 -0800 | [diff] [blame] | 55 | unsigned long background_thresh; |
| 56 | unsigned long dirty_thresh; |
| 57 | unsigned long bdi_thresh; |
Gustavo F. Padovan | 345227d | 2011-05-20 21:23:37 +0200 | [diff] [blame] | 58 | unsigned long nr_dirty, nr_io, nr_more_io; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 59 | struct inode *inode; |
| 60 | |
Gustavo F. Padovan | 345227d | 2011-05-20 21:23:37 +0200 | [diff] [blame] | 61 | nr_dirty = nr_io = nr_more_io = 0; |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 62 | spin_lock(&wb->list_lock); |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 63 | list_for_each_entry(inode, &wb->b_dirty, i_wb_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 64 | nr_dirty++; |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 65 | list_for_each_entry(inode, &wb->b_io, i_wb_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 66 | nr_io++; |
Nick Piggin | 7ccf19a | 2010-10-21 11:49:30 +1100 | [diff] [blame] | 67 | list_for_each_entry(inode, &wb->b_more_io, i_wb_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 68 | nr_more_io++; |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 69 | spin_unlock(&wb->list_lock); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 70 | |
Wu Fengguang | 16c4042 | 2010-08-11 14:17:39 -0700 | [diff] [blame] | 71 | global_dirty_limits(&background_thresh, &dirty_thresh); |
| 72 | bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 73 | |
| 74 | #define K(x) ((x) << (PAGE_SHIFT - 10)) |
| 75 | seq_printf(m, |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 76 | "BdiWriteback: %10lu kB\n" |
| 77 | "BdiReclaimable: %10lu kB\n" |
| 78 | "BdiDirtyThresh: %10lu kB\n" |
| 79 | "DirtyThresh: %10lu kB\n" |
| 80 | "BackgroundThresh: %10lu kB\n" |
Wu Fengguang | c8e28ce | 2011-01-23 10:07:47 -0600 | [diff] [blame] | 81 | "BdiDirtied: %10lu kB\n" |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 82 | "BdiWritten: %10lu kB\n" |
| 83 | "BdiWriteBandwidth: %10lu kBps\n" |
| 84 | "b_dirty: %10lu\n" |
| 85 | "b_io: %10lu\n" |
| 86 | "b_more_io: %10lu\n" |
| 87 | "bdi_list: %10u\n" |
| 88 | "state: %10lx\n", |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 89 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), |
| 90 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 91 | K(bdi_thresh), |
| 92 | K(dirty_thresh), |
| 93 | K(background_thresh), |
Wu Fengguang | c8e28ce | 2011-01-23 10:07:47 -0600 | [diff] [blame] | 94 | (unsigned long) K(bdi_stat(bdi, BDI_DIRTIED)), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 95 | (unsigned long) K(bdi_stat(bdi, BDI_WRITTEN)), |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 96 | (unsigned long) K(bdi->write_bandwidth), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 97 | nr_dirty, |
| 98 | nr_io, |
| 99 | nr_more_io, |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 100 | !list_empty(&bdi->bdi_list), bdi->state); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 101 | #undef K |
| 102 | |
| 103 | return 0; |
| 104 | } |
| 105 | |
| 106 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) |
| 107 | { |
| 108 | return single_open(file, bdi_debug_stats_show, inode->i_private); |
| 109 | } |
| 110 | |
| 111 | static const struct file_operations bdi_debug_stats_fops = { |
| 112 | .open = bdi_debug_stats_open, |
| 113 | .read = seq_read, |
| 114 | .llseek = seq_lseek, |
| 115 | .release = single_release, |
| 116 | }; |
| 117 | |
| 118 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) |
| 119 | { |
| 120 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); |
| 121 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, |
| 122 | bdi, &bdi_debug_stats_fops); |
| 123 | } |
| 124 | |
| 125 | static void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 126 | { |
| 127 | debugfs_remove(bdi->debug_stats); |
| 128 | debugfs_remove(bdi->debug_dir); |
| 129 | } |
| 130 | #else |
| 131 | static inline void bdi_debug_init(void) |
| 132 | { |
| 133 | } |
| 134 | static inline void bdi_debug_register(struct backing_dev_info *bdi, |
| 135 | const char *name) |
| 136 | { |
| 137 | } |
| 138 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 139 | { |
| 140 | } |
| 141 | #endif |
| 142 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 143 | static ssize_t read_ahead_kb_store(struct device *dev, |
| 144 | struct device_attribute *attr, |
| 145 | const char *buf, size_t count) |
| 146 | { |
| 147 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 148 | unsigned long read_ahead_kb; |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 149 | ssize_t ret; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 150 | |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 151 | ret = kstrtoul(buf, 10, &read_ahead_kb); |
| 152 | if (ret < 0) |
| 153 | return ret; |
| 154 | |
| 155 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); |
| 156 | |
| 157 | return count; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 158 | } |
| 159 | |
| 160 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) |
| 161 | |
| 162 | #define BDI_SHOW(name, expr) \ |
| 163 | static ssize_t name##_show(struct device *dev, \ |
| 164 | struct device_attribute *attr, char *page) \ |
| 165 | { \ |
| 166 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ |
| 167 | \ |
| 168 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ |
Greg Kroah-Hartman | d9e1241 | 2013-07-24 15:05:26 -0700 | [diff] [blame] | 169 | } \ |
| 170 | static DEVICE_ATTR_RW(name); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 171 | |
| 172 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) |
| 173 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 174 | static ssize_t min_ratio_store(struct device *dev, |
| 175 | struct device_attribute *attr, const char *buf, size_t count) |
| 176 | { |
| 177 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 178 | unsigned int ratio; |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 179 | ssize_t ret; |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 180 | |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 181 | ret = kstrtouint(buf, 10, &ratio); |
| 182 | if (ret < 0) |
| 183 | return ret; |
| 184 | |
| 185 | ret = bdi_set_min_ratio(bdi, ratio); |
| 186 | if (!ret) |
| 187 | ret = count; |
| 188 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 189 | return ret; |
| 190 | } |
| 191 | BDI_SHOW(min_ratio, bdi->min_ratio) |
| 192 | |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 193 | static ssize_t max_ratio_store(struct device *dev, |
| 194 | struct device_attribute *attr, const char *buf, size_t count) |
| 195 | { |
| 196 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 197 | unsigned int ratio; |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 198 | ssize_t ret; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 199 | |
Namjae Jeon | 7034ed1 | 2012-08-25 16:57:27 +0800 | [diff] [blame] | 200 | ret = kstrtouint(buf, 10, &ratio); |
| 201 | if (ret < 0) |
| 202 | return ret; |
| 203 | |
| 204 | ret = bdi_set_max_ratio(bdi, ratio); |
| 205 | if (!ret) |
| 206 | ret = count; |
| 207 | |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 208 | return ret; |
| 209 | } |
| 210 | BDI_SHOW(max_ratio, bdi->max_ratio) |
| 211 | |
Darrick J. Wong | 7d311cd | 2013-02-21 16:42:48 -0800 | [diff] [blame] | 212 | static ssize_t stable_pages_required_show(struct device *dev, |
| 213 | struct device_attribute *attr, |
| 214 | char *page) |
| 215 | { |
| 216 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 217 | |
| 218 | return snprintf(page, PAGE_SIZE-1, "%d\n", |
| 219 | bdi_cap_stable_pages_required(bdi) ? 1 : 0); |
| 220 | } |
Greg Kroah-Hartman | d9e1241 | 2013-07-24 15:05:26 -0700 | [diff] [blame] | 221 | static DEVICE_ATTR_RO(stable_pages_required); |
Darrick J. Wong | 7d311cd | 2013-02-21 16:42:48 -0800 | [diff] [blame] | 222 | |
Greg Kroah-Hartman | d9e1241 | 2013-07-24 15:05:26 -0700 | [diff] [blame] | 223 | static struct attribute *bdi_dev_attrs[] = { |
| 224 | &dev_attr_read_ahead_kb.attr, |
| 225 | &dev_attr_min_ratio.attr, |
| 226 | &dev_attr_max_ratio.attr, |
| 227 | &dev_attr_stable_pages_required.attr, |
| 228 | NULL, |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 229 | }; |
Greg Kroah-Hartman | d9e1241 | 2013-07-24 15:05:26 -0700 | [diff] [blame] | 230 | ATTRIBUTE_GROUPS(bdi_dev); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 231 | |
| 232 | static __init int bdi_class_init(void) |
| 233 | { |
| 234 | bdi_class = class_create(THIS_MODULE, "bdi"); |
Anton Blanchard | 1442145 | 2010-04-02 09:46:55 +0200 | [diff] [blame] | 235 | if (IS_ERR(bdi_class)) |
| 236 | return PTR_ERR(bdi_class); |
| 237 | |
Greg Kroah-Hartman | d9e1241 | 2013-07-24 15:05:26 -0700 | [diff] [blame] | 238 | bdi_class->dev_groups = bdi_dev_groups; |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 239 | bdi_debug_init(); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 240 | return 0; |
| 241 | } |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 242 | postcore_initcall(bdi_class_init); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 243 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 244 | static int __init default_bdi_init(void) |
| 245 | { |
| 246 | int err; |
| 247 | |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 248 | bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_FREEZABLE | |
Tejun Heo | b5c872d | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 249 | WQ_UNBOUND | WQ_SYSFS, 0); |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 250 | if (!bdi_wq) |
| 251 | return -ENOMEM; |
| 252 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 253 | err = bdi_init(&default_backing_dev_info); |
| 254 | if (!err) |
| 255 | bdi_register(&default_backing_dev_info, NULL, "default"); |
Jan Kara | 976e48f | 2010-09-21 11:48:55 +0200 | [diff] [blame] | 256 | err = bdi_init(&noop_backing_dev_info); |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 257 | |
| 258 | return err; |
| 259 | } |
| 260 | subsys_initcall(default_bdi_init); |
| 261 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 262 | int bdi_has_dirty_io(struct backing_dev_info *bdi) |
| 263 | { |
| 264 | return wb_has_dirty_io(&bdi->wb); |
| 265 | } |
| 266 | |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 267 | /* |
| 268 | * This function is used when the first inode for this bdi is marked dirty. It |
| 269 | * wakes-up the corresponding bdi thread which should then take care of the |
| 270 | * periodic background write-out of dirty inodes. Since the write-out would |
| 271 | * starts only 'dirty_writeback_interval' centisecs from now anyway, we just |
| 272 | * set up a timer which wakes the bdi thread up later. |
| 273 | * |
| 274 | * Note, we wouldn't bother setting up the timer, but this function is on the |
| 275 | * fast-path (used by '__mark_inode_dirty()'), so we save few context switches |
| 276 | * by delaying the wake-up. |
Derek Basehore | 6ca738d | 2014-04-03 14:46:22 -0700 | [diff] [blame] | 277 | * |
| 278 | * We have to be careful not to postpone flush work if it is scheduled for |
| 279 | * earlier. Thus we use queue_delayed_work(). |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 280 | */ |
| 281 | void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi) |
| 282 | { |
| 283 | unsigned long timeout; |
| 284 | |
| 285 | timeout = msecs_to_jiffies(dirty_writeback_interval * 10); |
Jan Kara | 5acda9d | 2014-04-03 14:46:23 -0700 | [diff] [blame] | 286 | spin_lock_bh(&bdi->wb_lock); |
| 287 | if (test_bit(BDI_registered, &bdi->state)) |
| 288 | queue_delayed_work(bdi_wq, &bdi->wb.dwork, timeout); |
| 289 | spin_unlock_bh(&bdi->wb_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 290 | } |
| 291 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 292 | /* |
| 293 | * Remove bdi from bdi_list, and ensure that it is no longer visible |
| 294 | */ |
| 295 | static void bdi_remove_from_list(struct backing_dev_info *bdi) |
| 296 | { |
| 297 | spin_lock_bh(&bdi_lock); |
| 298 | list_del_rcu(&bdi->bdi_list); |
| 299 | spin_unlock_bh(&bdi_lock); |
| 300 | |
Mikulas Patocka | ef32308 | 2011-07-23 20:44:24 +0200 | [diff] [blame] | 301 | synchronize_rcu_expedited(); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 302 | } |
| 303 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 304 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| 305 | const char *fmt, ...) |
| 306 | { |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 307 | va_list args; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 308 | struct device *dev; |
| 309 | |
Andrew Morton | 69fc208 | 2008-12-09 13:14:06 -0800 | [diff] [blame] | 310 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 311 | return 0; |
Kay Sievers | f1d0b06 | 2008-12-02 10:31:50 -0800 | [diff] [blame] | 312 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 313 | va_start(args, fmt); |
Greg Kroah-Hartman | 19051c5 | 2008-05-15 13:44:08 -0700 | [diff] [blame] | 314 | 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] | 315 | va_end(args); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 316 | if (IS_ERR(dev)) |
| 317 | return PTR_ERR(dev); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 318 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 319 | bdi->dev = dev; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 320 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 321 | bdi_debug_register(bdi, dev_name(dev)); |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 322 | set_bit(BDI_registered, &bdi->state); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 323 | |
| 324 | spin_lock_bh(&bdi_lock); |
| 325 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
| 326 | spin_unlock_bh(&bdi_lock); |
| 327 | |
Dave Chinner | 455b286 | 2010-07-07 13:24:06 +1000 | [diff] [blame] | 328 | trace_writeback_bdi_register(bdi); |
Artem Bityutskiy | c284de6 | 2010-07-25 14:29:25 +0300 | [diff] [blame] | 329 | return 0; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 330 | } |
| 331 | EXPORT_SYMBOL(bdi_register); |
| 332 | |
| 333 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) |
| 334 | { |
| 335 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); |
| 336 | } |
| 337 | EXPORT_SYMBOL(bdi_register_dev); |
| 338 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 339 | /* |
| 340 | * Remove bdi from the global list and shutdown any threads we have running |
| 341 | */ |
| 342 | static void bdi_wb_shutdown(struct backing_dev_info *bdi) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 343 | { |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 344 | /* Make sure nobody queues further work */ |
| 345 | spin_lock_bh(&bdi->wb_lock); |
| 346 | if (!test_and_clear_bit(BDI_registered, &bdi->state)) { |
| 347 | spin_unlock_bh(&bdi->wb_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 348 | return; |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 349 | } |
| 350 | spin_unlock_bh(&bdi->wb_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 351 | |
| 352 | /* |
Artem Bityutskiy | fff5b85 | 2010-07-25 14:29:20 +0300 | [diff] [blame] | 353 | * Make sure nobody finds us on the bdi_list anymore |
| 354 | */ |
| 355 | bdi_remove_from_list(bdi); |
| 356 | |
| 357 | /* |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 358 | * Drain work list and shutdown the delayed_work. At this point, |
| 359 | * @bdi->bdi_list is empty telling bdi_Writeback_workfn() that @bdi |
| 360 | * is dying and its work_list needs to be drained no matter what. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 361 | */ |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 362 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
| 363 | flush_delayed_work(&bdi->wb.dwork); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 364 | } |
| 365 | |
Jens Axboe | 592b09a | 2009-10-29 11:46:12 +0100 | [diff] [blame] | 366 | /* |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 367 | * Called when the device behind @bdi has been removed or ejected. |
| 368 | * |
| 369 | * We can't really do much here except for reducing the dirty ratio at |
| 370 | * the moment. In the future we should be able to set a flag so that |
| 371 | * the filesystem can handle errors at mark_inode_dirty time instead |
| 372 | * of only at writeback time. |
Jens Axboe | 592b09a | 2009-10-29 11:46:12 +0100 | [diff] [blame] | 373 | */ |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 374 | void bdi_unregister(struct backing_dev_info *bdi) |
| 375 | { |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 376 | if (WARN_ON_ONCE(!bdi->dev)) |
| 377 | return; |
Jens Axboe | 8c4db33 | 2009-11-03 20:18:44 +0100 | [diff] [blame] | 378 | |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 379 | bdi_set_min_ratio(bdi, 0); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 380 | } |
| 381 | EXPORT_SYMBOL(bdi_unregister); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 382 | |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 383 | static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) |
| 384 | { |
| 385 | memset(wb, 0, sizeof(*wb)); |
| 386 | |
| 387 | wb->bdi = bdi; |
| 388 | wb->last_old_flush = jiffies; |
| 389 | INIT_LIST_HEAD(&wb->b_dirty); |
| 390 | INIT_LIST_HEAD(&wb->b_io); |
| 391 | INIT_LIST_HEAD(&wb->b_more_io); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 392 | spin_lock_init(&wb->list_lock); |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 393 | INIT_DELAYED_WORK(&wb->dwork, bdi_writeback_workfn); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 394 | } |
| 395 | |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 396 | /* |
| 397 | * Initial write bandwidth: 100 MB/s |
| 398 | */ |
| 399 | #define INIT_BW (100 << (20 - PAGE_SHIFT)) |
| 400 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 401 | int bdi_init(struct backing_dev_info *bdi) |
| 402 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 403 | int i, err; |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 404 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 405 | bdi->dev = NULL; |
| 406 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 407 | bdi->min_ratio = 0; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 408 | bdi->max_ratio = 100; |
Jan Kara | eb608e3 | 2012-05-24 18:59:11 +0200 | [diff] [blame] | 409 | bdi->max_prop_frac = FPROP_FRAC_BASE; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 410 | spin_lock_init(&bdi->wb_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 411 | INIT_LIST_HEAD(&bdi->bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 412 | INIT_LIST_HEAD(&bdi->work_list); |
| 413 | |
| 414 | bdi_wb_init(&bdi->wb, bdi); |
| 415 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 416 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
Tejun Heo | 908c7f1 | 2014-09-08 09:51:29 +0900 | [diff] [blame] | 417 | err = percpu_counter_init(&bdi->bdi_stat[i], 0, GFP_KERNEL); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 418 | if (err) |
| 419 | goto err; |
| 420 | } |
| 421 | |
| 422 | bdi->dirty_exceeded = 0; |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 423 | |
| 424 | bdi->bw_time_stamp = jiffies; |
| 425 | bdi->written_stamp = 0; |
| 426 | |
Wu Fengguang | 7381131 | 2011-08-26 15:53:24 -0600 | [diff] [blame] | 427 | bdi->balanced_dirty_ratelimit = INIT_BW; |
Wu Fengguang | be3ffa2 | 2011-06-12 10:51:31 -0600 | [diff] [blame] | 428 | bdi->dirty_ratelimit = INIT_BW; |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 429 | bdi->write_bandwidth = INIT_BW; |
| 430 | bdi->avg_write_bandwidth = INIT_BW; |
| 431 | |
Tejun Heo | 20ae007 | 2014-09-08 09:51:30 +0900 | [diff] [blame] | 432 | err = fprop_local_init_percpu(&bdi->completions, GFP_KERNEL); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 433 | |
| 434 | if (err) { |
| 435 | err: |
Denis Cheng | 4b01a0b | 2007-12-04 23:45:07 -0800 | [diff] [blame] | 436 | while (i--) |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 437 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 438 | } |
| 439 | |
| 440 | return err; |
| 441 | } |
| 442 | EXPORT_SYMBOL(bdi_init); |
| 443 | |
| 444 | void bdi_destroy(struct backing_dev_info *bdi) |
| 445 | { |
| 446 | int i; |
| 447 | |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 448 | bdi_wb_shutdown(bdi); |
Jens Axboe | ce5f8e7 | 2009-09-14 12:57:56 +0200 | [diff] [blame] | 449 | |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 450 | WARN_ON(!list_empty(&bdi->work_list)); |
Tejun Heo | c0ea1c2 | 2014-09-08 08:03:59 +0900 | [diff] [blame] | 451 | WARN_ON(delayed_work_pending(&bdi->wb.dwork)); |
Rabin Vincent | 7a401a9 | 2011-11-11 13:29:04 +0100 | [diff] [blame] | 452 | |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame^] | 453 | if (bdi->dev) { |
| 454 | bdi_debug_unregister(bdi); |
| 455 | device_unregister(bdi->dev); |
| 456 | bdi->dev = NULL; |
| 457 | } |
| 458 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 459 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
| 460 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Jan Kara | eb608e3 | 2012-05-24 18:59:11 +0200 | [diff] [blame] | 461 | fprop_local_destroy_percpu(&bdi->completions); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 462 | } |
| 463 | EXPORT_SYMBOL(bdi_destroy); |
| 464 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 465 | /* |
| 466 | * For use from filesystems to quickly init and register a bdi associated |
| 467 | * with dirty writeback |
| 468 | */ |
Christoph Hellwig | b4caecd | 2015-01-14 10:42:32 +0100 | [diff] [blame] | 469 | int bdi_setup_and_register(struct backing_dev_info *bdi, char *name) |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 470 | { |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 471 | int err; |
| 472 | |
| 473 | bdi->name = name; |
Christoph Hellwig | b4caecd | 2015-01-14 10:42:32 +0100 | [diff] [blame] | 474 | bdi->capabilities = 0; |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 475 | err = bdi_init(bdi); |
| 476 | if (err) |
| 477 | return err; |
| 478 | |
Kees Cook | 02aa2a3 | 2013-07-03 15:04:56 -0700 | [diff] [blame] | 479 | err = bdi_register(bdi, NULL, "%.28s-%ld", name, |
| 480 | atomic_long_inc_return(&bdi_seq)); |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 481 | if (err) { |
| 482 | bdi_destroy(bdi); |
| 483 | return err; |
| 484 | } |
| 485 | |
| 486 | return 0; |
| 487 | } |
| 488 | EXPORT_SYMBOL(bdi_setup_and_register); |
| 489 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 490 | static wait_queue_head_t congestion_wqh[2] = { |
| 491 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), |
| 492 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) |
| 493 | }; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 494 | static atomic_t nr_bdi_congested[2]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 495 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 496 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 497 | { |
| 498 | enum bdi_state bit; |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 499 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 500 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 501 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 502 | if (test_and_clear_bit(bit, &bdi->state)) |
| 503 | atomic_dec(&nr_bdi_congested[sync]); |
Peter Zijlstra | 4e857c5 | 2014-03-17 18:06:10 +0100 | [diff] [blame] | 504 | smp_mb__after_atomic(); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 505 | if (waitqueue_active(wqh)) |
| 506 | wake_up(wqh); |
| 507 | } |
| 508 | EXPORT_SYMBOL(clear_bdi_congested); |
| 509 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 510 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 511 | { |
| 512 | enum bdi_state bit; |
| 513 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 514 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 515 | if (!test_and_set_bit(bit, &bdi->state)) |
| 516 | atomic_inc(&nr_bdi_congested[sync]); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 517 | } |
| 518 | EXPORT_SYMBOL(set_bdi_congested); |
| 519 | |
| 520 | /** |
| 521 | * congestion_wait - wait for a backing_dev to become uncongested |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 522 | * @sync: SYNC or ASYNC IO |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 523 | * @timeout: timeout in jiffies |
| 524 | * |
| 525 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit |
| 526 | * write congestion. If no backing_devs are congested then just wait for the |
| 527 | * next write to be completed. |
| 528 | */ |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 529 | long congestion_wait(int sync, long timeout) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 530 | { |
| 531 | long ret; |
Mel Gorman | 52bb919 | 2010-10-26 14:21:41 -0700 | [diff] [blame] | 532 | unsigned long start = jiffies; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 533 | DEFINE_WAIT(wait); |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 534 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 535 | |
| 536 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 537 | ret = io_schedule_timeout(timeout); |
| 538 | finish_wait(wqh, &wait); |
Mel Gorman | 52bb919 | 2010-10-26 14:21:41 -0700 | [diff] [blame] | 539 | |
| 540 | trace_writeback_congestion_wait(jiffies_to_usecs(timeout), |
| 541 | jiffies_to_usecs(jiffies - start)); |
| 542 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 543 | return ret; |
| 544 | } |
| 545 | EXPORT_SYMBOL(congestion_wait); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 546 | |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 547 | /** |
| 548 | * wait_iff_congested - Conditionally wait for a backing_dev to become uncongested or a zone to complete writes |
| 549 | * @zone: A zone to check if it is heavily congested |
| 550 | * @sync: SYNC or ASYNC IO |
| 551 | * @timeout: timeout in jiffies |
| 552 | * |
| 553 | * In the event of a congested backing_dev (any backing_dev) and the given |
| 554 | * @zone has experienced recent congestion, this waits for up to @timeout |
| 555 | * jiffies for either a BDI to exit congestion of the given @sync queue |
| 556 | * or a write to complete. |
| 557 | * |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 558 | * In the absence of zone congestion, cond_resched() is called to yield |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 559 | * the processor if necessary but otherwise does not sleep. |
| 560 | * |
| 561 | * The return value is 0 if the sleep is for the full timeout. Otherwise, |
| 562 | * it is the number of jiffies that were still remaining when the function |
| 563 | * returned. return_value == timeout implies the function did not sleep. |
| 564 | */ |
| 565 | long wait_iff_congested(struct zone *zone, int sync, long timeout) |
| 566 | { |
| 567 | long ret; |
| 568 | unsigned long start = jiffies; |
| 569 | DEFINE_WAIT(wait); |
| 570 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
| 571 | |
| 572 | /* |
| 573 | * If there is no congestion, or heavy congestion is not being |
| 574 | * encountered in the current zone, yield if necessary instead |
| 575 | * of sleeping on the congestion queue |
| 576 | */ |
| 577 | if (atomic_read(&nr_bdi_congested[sync]) == 0 || |
Johannes Weiner | 5705465 | 2014-10-09 15:28:17 -0700 | [diff] [blame] | 578 | !test_bit(ZONE_CONGESTED, &zone->flags)) { |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 579 | cond_resched(); |
| 580 | |
| 581 | /* In case we scheduled, work out time remaining */ |
| 582 | ret = timeout - (jiffies - start); |
| 583 | if (ret < 0) |
| 584 | ret = 0; |
| 585 | |
| 586 | goto out; |
| 587 | } |
| 588 | |
| 589 | /* Sleep until uncongested or a write happens */ |
| 590 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 591 | ret = io_schedule_timeout(timeout); |
| 592 | finish_wait(wqh, &wait); |
| 593 | |
| 594 | out: |
| 595 | trace_writeback_wait_iff_congested(jiffies_to_usecs(timeout), |
| 596 | jiffies_to_usecs(jiffies - start)); |
| 597 | |
| 598 | return ret; |
| 599 | } |
| 600 | EXPORT_SYMBOL(wait_iff_congested); |
Wanpeng Li | 3965c9a | 2012-07-31 16:41:52 -0700 | [diff] [blame] | 601 | |
| 602 | int pdflush_proc_obsolete(struct ctl_table *table, int write, |
| 603 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 604 | { |
| 605 | char kbuf[] = "0\n"; |
| 606 | |
Chen Gang | 4c3bffc | 2013-09-11 14:22:44 -0700 | [diff] [blame] | 607 | if (*ppos || *lenp < sizeof(kbuf)) { |
Wanpeng Li | 3965c9a | 2012-07-31 16:41:52 -0700 | [diff] [blame] | 608 | *lenp = 0; |
| 609 | return 0; |
| 610 | } |
| 611 | |
| 612 | if (copy_to_user(buffer, kbuf, sizeof(kbuf))) |
| 613 | return -EFAULT; |
| 614 | printk_once(KERN_WARNING "%s exported in /proc is scheduled for removal\n", |
| 615 | table->procname); |
| 616 | |
| 617 | *lenp = 2; |
| 618 | *ppos += *lenp; |
| 619 | return 2; |
| 620 | } |