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 | |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 17 | struct backing_dev_info noop_backing_dev_info = { |
| 18 | .name = "noop", |
Jan Kara | 976e48f | 2010-09-21 11:48:55 +0200 | [diff] [blame] | 19 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 20 | }; |
Tejun Heo | a212b10 | 2015-05-22 17:13:33 -0400 | [diff] [blame] | 21 | EXPORT_SYMBOL_GPL(noop_backing_dev_info); |
Jörn Engel | 5129a46 | 2010-04-25 08:54:42 +0200 | [diff] [blame] | 22 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 23 | static struct class *bdi_class; |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 24 | |
| 25 | /* |
Tejun Heo | 181387d | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 26 | * 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] | 27 | * locking. |
| 28 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 29 | DEFINE_SPINLOCK(bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 30 | LIST_HEAD(bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 31 | |
Tejun Heo | 839a8e8 | 2013-04-01 19:08:06 -0700 | [diff] [blame] | 32 | /* bdi_wq serves all asynchronous writeback tasks */ |
| 33 | struct workqueue_struct *bdi_wq; |
| 34 | |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 35 | #ifdef CONFIG_DEBUG_FS |
| 36 | #include <linux/debugfs.h> |
| 37 | #include <linux/seq_file.h> |
| 38 | |
| 39 | static struct dentry *bdi_debug_root; |
| 40 | |
| 41 | static void bdi_debug_init(void) |
| 42 | { |
| 43 | bdi_debug_root = debugfs_create_dir("bdi", NULL); |
| 44 | } |
| 45 | |
| 46 | static int bdi_debug_stats_show(struct seq_file *m, void *v) |
| 47 | { |
| 48 | struct backing_dev_info *bdi = m->private; |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 49 | struct bdi_writeback *wb = &bdi->wb; |
David Rientjes | 364aeb2 | 2009-01-06 14:39:29 -0800 | [diff] [blame] | 50 | unsigned long background_thresh; |
| 51 | unsigned long dirty_thresh; |
Tejun Heo | 0d960a3 | 2015-05-22 18:23:19 -0400 | [diff] [blame] | 52 | unsigned long wb_thresh; |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 53 | unsigned long nr_dirty, nr_io, nr_more_io, nr_dirty_time; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 54 | struct inode *inode; |
| 55 | |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 56 | nr_dirty = nr_io = nr_more_io = nr_dirty_time = 0; |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 57 | spin_lock(&wb->list_lock); |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 58 | list_for_each_entry(inode, &wb->b_dirty, i_io_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 59 | nr_dirty++; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 60 | list_for_each_entry(inode, &wb->b_io, i_io_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 61 | nr_io++; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 62 | list_for_each_entry(inode, &wb->b_more_io, i_io_list) |
Christoph Hellwig | c1955ce | 2010-06-19 23:08:06 +0200 | [diff] [blame] | 63 | nr_more_io++; |
Dave Chinner | c7f5408 | 2015-03-04 14:07:22 -0500 | [diff] [blame] | 64 | list_for_each_entry(inode, &wb->b_dirty_time, i_io_list) |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 65 | if (inode->i_state & I_DIRTY_TIME) |
| 66 | nr_dirty_time++; |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 67 | spin_unlock(&wb->list_lock); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 68 | |
Wu Fengguang | 16c4042 | 2010-08-11 14:17:39 -0700 | [diff] [blame] | 69 | global_dirty_limits(&background_thresh, &dirty_thresh); |
Tejun Heo | 0d960a3 | 2015-05-22 18:23:19 -0400 | [diff] [blame] | 70 | wb_thresh = wb_calc_thresh(wb, dirty_thresh); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 71 | |
| 72 | #define K(x) ((x) << (PAGE_SHIFT - 10)) |
| 73 | seq_printf(m, |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 74 | "BdiWriteback: %10lu kB\n" |
| 75 | "BdiReclaimable: %10lu kB\n" |
| 76 | "BdiDirtyThresh: %10lu kB\n" |
| 77 | "DirtyThresh: %10lu kB\n" |
| 78 | "BackgroundThresh: %10lu kB\n" |
Wu Fengguang | c8e28ce | 2011-01-23 10:07:47 -0600 | [diff] [blame] | 79 | "BdiDirtied: %10lu kB\n" |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 80 | "BdiWritten: %10lu kB\n" |
| 81 | "BdiWriteBandwidth: %10lu kBps\n" |
| 82 | "b_dirty: %10lu\n" |
| 83 | "b_io: %10lu\n" |
| 84 | "b_more_io: %10lu\n" |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 85 | "b_dirty_time: %10lu\n" |
Wu Fengguang | 00821b0 | 2010-08-29 11:28:45 -0600 | [diff] [blame] | 86 | "bdi_list: %10u\n" |
| 87 | "state: %10lx\n", |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 88 | (unsigned long) K(wb_stat(wb, WB_WRITEBACK)), |
| 89 | (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)), |
Tejun Heo | 0d960a3 | 2015-05-22 18:23:19 -0400 | [diff] [blame] | 90 | K(wb_thresh), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 91 | K(dirty_thresh), |
| 92 | K(background_thresh), |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 93 | (unsigned long) K(wb_stat(wb, WB_DIRTIED)), |
| 94 | (unsigned long) K(wb_stat(wb, WB_WRITTEN)), |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 95 | (unsigned long) K(wb->write_bandwidth), |
Jan Kara | f7d2b1e | 2010-12-08 22:44:24 -0600 | [diff] [blame] | 96 | nr_dirty, |
| 97 | nr_io, |
| 98 | nr_more_io, |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 99 | nr_dirty_time, |
Tejun Heo | 4452226 | 2015-05-22 17:13:26 -0400 | [diff] [blame] | 100 | !list_empty(&bdi->bdi_list), bdi->wb.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 | |
Jan Kara | 976e48f | 2010-09-21 11:48:55 +0200 | [diff] [blame] | 253 | err = bdi_init(&noop_backing_dev_info); |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 254 | |
| 255 | return err; |
| 256 | } |
| 257 | subsys_initcall(default_bdi_init); |
| 258 | |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 259 | /* |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 260 | * This function is used when the first inode for this wb is marked dirty. It |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 261 | * wakes-up the corresponding bdi thread which should then take care of the |
| 262 | * periodic background write-out of dirty inodes. Since the write-out would |
| 263 | * starts only 'dirty_writeback_interval' centisecs from now anyway, we just |
| 264 | * set up a timer which wakes the bdi thread up later. |
| 265 | * |
| 266 | * Note, we wouldn't bother setting up the timer, but this function is on the |
| 267 | * fast-path (used by '__mark_inode_dirty()'), so we save few context switches |
| 268 | * by delaying the wake-up. |
Derek Basehore | 6ca738d | 2014-04-03 14:46:22 -0700 | [diff] [blame] | 269 | * |
| 270 | * We have to be careful not to postpone flush work if it is scheduled for |
| 271 | * earlier. Thus we use queue_delayed_work(). |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 272 | */ |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 273 | void wb_wakeup_delayed(struct bdi_writeback *wb) |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 274 | { |
| 275 | unsigned long timeout; |
| 276 | |
| 277 | timeout = msecs_to_jiffies(dirty_writeback_interval * 10); |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 278 | spin_lock_bh(&wb->work_lock); |
| 279 | if (test_bit(WB_registered, &wb->state)) |
| 280 | queue_delayed_work(bdi_wq, &wb->dwork, timeout); |
| 281 | spin_unlock_bh(&wb->work_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 282 | } |
| 283 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 284 | /* |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 285 | * Initial write bandwidth: 100 MB/s |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 286 | */ |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 287 | #define INIT_BW (100 << (20 - PAGE_SHIFT)) |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 288 | |
Tejun Heo | 8395cd9 | 2015-05-22 17:13:34 -0400 | [diff] [blame] | 289 | static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi, |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 290 | int blkcg_id, gfp_t gfp) |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 291 | { |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 292 | int i, err; |
| 293 | |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 294 | memset(wb, 0, sizeof(*wb)); |
| 295 | |
| 296 | wb->bdi = bdi; |
| 297 | wb->last_old_flush = jiffies; |
| 298 | INIT_LIST_HEAD(&wb->b_dirty); |
| 299 | INIT_LIST_HEAD(&wb->b_io); |
| 300 | INIT_LIST_HEAD(&wb->b_more_io); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 301 | INIT_LIST_HEAD(&wb->b_dirty_time); |
Christoph Hellwig | f758eea | 2011-04-21 18:19:44 -0600 | [diff] [blame] | 302 | spin_lock_init(&wb->list_lock); |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 303 | |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 304 | wb->bw_time_stamp = jiffies; |
| 305 | wb->balanced_dirty_ratelimit = INIT_BW; |
| 306 | wb->dirty_ratelimit = INIT_BW; |
| 307 | wb->write_bandwidth = INIT_BW; |
| 308 | wb->avg_write_bandwidth = INIT_BW; |
| 309 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 310 | spin_lock_init(&wb->work_lock); |
| 311 | INIT_LIST_HEAD(&wb->work_list); |
| 312 | INIT_DELAYED_WORK(&wb->dwork, wb_workfn); |
| 313 | |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 314 | wb->congested = wb_congested_get_create(bdi, blkcg_id, gfp); |
| 315 | if (!wb->congested) |
| 316 | return -ENOMEM; |
| 317 | |
Tejun Heo | 8395cd9 | 2015-05-22 17:13:34 -0400 | [diff] [blame] | 318 | err = fprop_local_init_percpu(&wb->completions, gfp); |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 319 | if (err) |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 320 | goto out_put_cong; |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 321 | |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 322 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) { |
Tejun Heo | 8395cd9 | 2015-05-22 17:13:34 -0400 | [diff] [blame] | 323 | err = percpu_counter_init(&wb->stat[i], 0, gfp); |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 324 | if (err) |
| 325 | goto out_destroy_stat; |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 326 | } |
| 327 | |
| 328 | return 0; |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 329 | |
| 330 | out_destroy_stat: |
Rasmus Villemoes | 078c6c3 | 2016-02-11 16:13:06 -0800 | [diff] [blame] | 331 | while (i--) |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 332 | percpu_counter_destroy(&wb->stat[i]); |
| 333 | fprop_local_destroy_percpu(&wb->completions); |
| 334 | out_put_cong: |
| 335 | wb_congested_put(wb->congested); |
| 336 | return err; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 337 | } |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 338 | |
Tejun Heo | 4610007 | 2015-05-22 17:13:31 -0400 | [diff] [blame] | 339 | /* |
| 340 | * Remove bdi from the global list and shutdown any threads we have running |
| 341 | */ |
| 342 | static void wb_shutdown(struct bdi_writeback *wb) |
| 343 | { |
| 344 | /* Make sure nobody queues further work */ |
| 345 | spin_lock_bh(&wb->work_lock); |
| 346 | if (!test_and_clear_bit(WB_registered, &wb->state)) { |
| 347 | spin_unlock_bh(&wb->work_lock); |
| 348 | return; |
| 349 | } |
| 350 | spin_unlock_bh(&wb->work_lock); |
| 351 | |
| 352 | /* |
| 353 | * Drain work list and shutdown the delayed_work. !WB_registered |
| 354 | * tells wb_workfn() that @wb is dying and its work_list needs to |
| 355 | * be drained no matter what. |
| 356 | */ |
| 357 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
| 358 | flush_delayed_work(&wb->dwork); |
| 359 | WARN_ON(!list_empty(&wb->work_list)); |
| 360 | } |
| 361 | |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 362 | static void wb_exit(struct bdi_writeback *wb) |
Tejun Heo | 93f78d8 | 2015-05-22 17:13:27 -0400 | [diff] [blame] | 363 | { |
| 364 | int i; |
| 365 | |
| 366 | WARN_ON(delayed_work_pending(&wb->dwork)); |
| 367 | |
| 368 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) |
| 369 | percpu_counter_destroy(&wb->stat[i]); |
Artem Bityutskiy | 6467716 | 2010-07-25 14:29:22 +0300 | [diff] [blame] | 370 | |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 371 | fprop_local_destroy_percpu(&wb->completions); |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 372 | wb_congested_put(wb->congested); |
Tejun Heo | a88a341 | 2015-05-22 17:13:28 -0400 | [diff] [blame] | 373 | } |
Wu Fengguang | e98be2d | 2010-08-29 11:22:30 -0600 | [diff] [blame] | 374 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 375 | #ifdef CONFIG_CGROUP_WRITEBACK |
| 376 | |
| 377 | #include <linux/memcontrol.h> |
| 378 | |
| 379 | /* |
| 380 | * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree, |
| 381 | * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_tree is also RCU |
| 382 | * protected. cgwb_release_wait is used to wait for the completion of cgwb |
| 383 | * releases from bdi destruction path. |
| 384 | */ |
| 385 | static DEFINE_SPINLOCK(cgwb_lock); |
| 386 | static DECLARE_WAIT_QUEUE_HEAD(cgwb_release_wait); |
| 387 | |
| 388 | /** |
| 389 | * wb_congested_get_create - get or create a wb_congested |
| 390 | * @bdi: associated bdi |
| 391 | * @blkcg_id: ID of the associated blkcg |
| 392 | * @gfp: allocation mask |
| 393 | * |
| 394 | * Look up the wb_congested for @blkcg_id on @bdi. If missing, create one. |
| 395 | * The returned wb_congested has its reference count incremented. Returns |
| 396 | * NULL on failure. |
| 397 | */ |
| 398 | struct bdi_writeback_congested * |
| 399 | wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp) |
| 400 | { |
| 401 | struct bdi_writeback_congested *new_congested = NULL, *congested; |
| 402 | struct rb_node **node, *parent; |
| 403 | unsigned long flags; |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 404 | retry: |
| 405 | spin_lock_irqsave(&cgwb_lock, flags); |
| 406 | |
| 407 | node = &bdi->cgwb_congested_tree.rb_node; |
| 408 | parent = NULL; |
| 409 | |
| 410 | while (*node != NULL) { |
| 411 | parent = *node; |
| 412 | congested = container_of(parent, struct bdi_writeback_congested, |
| 413 | rb_node); |
| 414 | if (congested->blkcg_id < blkcg_id) |
| 415 | node = &parent->rb_left; |
| 416 | else if (congested->blkcg_id > blkcg_id) |
| 417 | node = &parent->rb_right; |
| 418 | else |
| 419 | goto found; |
| 420 | } |
| 421 | |
| 422 | if (new_congested) { |
| 423 | /* !found and storage for new one already allocated, insert */ |
| 424 | congested = new_congested; |
| 425 | new_congested = NULL; |
| 426 | rb_link_node(&congested->rb_node, parent, node); |
| 427 | rb_insert_color(&congested->rb_node, &bdi->cgwb_congested_tree); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 428 | goto found; |
| 429 | } |
| 430 | |
| 431 | spin_unlock_irqrestore(&cgwb_lock, flags); |
| 432 | |
| 433 | /* allocate storage for new one and retry */ |
| 434 | new_congested = kzalloc(sizeof(*new_congested), gfp); |
| 435 | if (!new_congested) |
| 436 | return NULL; |
| 437 | |
| 438 | atomic_set(&new_congested->refcnt, 0); |
| 439 | new_congested->bdi = bdi; |
| 440 | new_congested->blkcg_id = blkcg_id; |
| 441 | goto retry; |
| 442 | |
| 443 | found: |
| 444 | atomic_inc(&congested->refcnt); |
| 445 | spin_unlock_irqrestore(&cgwb_lock, flags); |
| 446 | kfree(new_congested); |
| 447 | return congested; |
| 448 | } |
| 449 | |
| 450 | /** |
| 451 | * wb_congested_put - put a wb_congested |
| 452 | * @congested: wb_congested to put |
| 453 | * |
| 454 | * Put @congested and destroy it if the refcnt reaches zero. |
| 455 | */ |
| 456 | void wb_congested_put(struct bdi_writeback_congested *congested) |
| 457 | { |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 458 | unsigned long flags; |
| 459 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 460 | local_irq_save(flags); |
| 461 | if (!atomic_dec_and_lock(&congested->refcnt, &cgwb_lock)) { |
| 462 | local_irq_restore(flags); |
| 463 | return; |
| 464 | } |
| 465 | |
Tejun Heo | a20135f | 2015-07-01 20:53:37 -0400 | [diff] [blame] | 466 | /* bdi might already have been destroyed leaving @congested unlinked */ |
| 467 | if (congested->bdi) { |
| 468 | rb_erase(&congested->rb_node, |
| 469 | &congested->bdi->cgwb_congested_tree); |
| 470 | congested->bdi = NULL; |
| 471 | } |
| 472 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 473 | spin_unlock_irqrestore(&cgwb_lock, flags); |
| 474 | kfree(congested); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 475 | } |
| 476 | |
| 477 | static void cgwb_release_workfn(struct work_struct *work) |
| 478 | { |
| 479 | struct bdi_writeback *wb = container_of(work, struct bdi_writeback, |
| 480 | release_work); |
| 481 | struct backing_dev_info *bdi = wb->bdi; |
| 482 | |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 483 | spin_lock_irq(&cgwb_lock); |
| 484 | list_del_rcu(&wb->bdi_node); |
| 485 | spin_unlock_irq(&cgwb_lock); |
| 486 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 487 | wb_shutdown(wb); |
| 488 | |
| 489 | css_put(wb->memcg_css); |
| 490 | css_put(wb->blkcg_css); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 491 | |
Tejun Heo | 841710a | 2015-05-22 18:23:33 -0400 | [diff] [blame] | 492 | fprop_local_destroy_percpu(&wb->memcg_completions); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 493 | percpu_ref_exit(&wb->refcnt); |
| 494 | wb_exit(wb); |
| 495 | kfree_rcu(wb, rcu); |
| 496 | |
| 497 | if (atomic_dec_and_test(&bdi->usage_cnt)) |
| 498 | wake_up_all(&cgwb_release_wait); |
| 499 | } |
| 500 | |
| 501 | static void cgwb_release(struct percpu_ref *refcnt) |
| 502 | { |
| 503 | struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback, |
| 504 | refcnt); |
| 505 | schedule_work(&wb->release_work); |
| 506 | } |
| 507 | |
| 508 | static void cgwb_kill(struct bdi_writeback *wb) |
| 509 | { |
| 510 | lockdep_assert_held(&cgwb_lock); |
| 511 | |
| 512 | WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id)); |
| 513 | list_del(&wb->memcg_node); |
| 514 | list_del(&wb->blkcg_node); |
| 515 | percpu_ref_kill(&wb->refcnt); |
| 516 | } |
| 517 | |
| 518 | static int cgwb_create(struct backing_dev_info *bdi, |
| 519 | struct cgroup_subsys_state *memcg_css, gfp_t gfp) |
| 520 | { |
| 521 | struct mem_cgroup *memcg; |
| 522 | struct cgroup_subsys_state *blkcg_css; |
| 523 | struct blkcg *blkcg; |
| 524 | struct list_head *memcg_cgwb_list, *blkcg_cgwb_list; |
| 525 | struct bdi_writeback *wb; |
| 526 | unsigned long flags; |
| 527 | int ret = 0; |
| 528 | |
| 529 | memcg = mem_cgroup_from_css(memcg_css); |
Tejun Heo | c165b3e | 2015-08-18 14:55:29 -0700 | [diff] [blame] | 530 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 531 | blkcg = css_to_blkcg(blkcg_css); |
| 532 | memcg_cgwb_list = mem_cgroup_cgwb_list(memcg); |
| 533 | blkcg_cgwb_list = &blkcg->cgwb_list; |
| 534 | |
| 535 | /* look up again under lock and discard on blkcg mismatch */ |
| 536 | spin_lock_irqsave(&cgwb_lock, flags); |
| 537 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); |
| 538 | if (wb && wb->blkcg_css != blkcg_css) { |
| 539 | cgwb_kill(wb); |
| 540 | wb = NULL; |
| 541 | } |
| 542 | spin_unlock_irqrestore(&cgwb_lock, flags); |
| 543 | if (wb) |
| 544 | goto out_put; |
| 545 | |
| 546 | /* need to create a new one */ |
| 547 | wb = kmalloc(sizeof(*wb), gfp); |
| 548 | if (!wb) |
| 549 | return -ENOMEM; |
| 550 | |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 551 | ret = wb_init(wb, bdi, blkcg_css->id, gfp); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 552 | if (ret) |
| 553 | goto err_free; |
| 554 | |
| 555 | ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp); |
| 556 | if (ret) |
| 557 | goto err_wb_exit; |
| 558 | |
Tejun Heo | 841710a | 2015-05-22 18:23:33 -0400 | [diff] [blame] | 559 | ret = fprop_local_init_percpu(&wb->memcg_completions, gfp); |
| 560 | if (ret) |
| 561 | goto err_ref_exit; |
| 562 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 563 | wb->memcg_css = memcg_css; |
| 564 | wb->blkcg_css = blkcg_css; |
| 565 | INIT_WORK(&wb->release_work, cgwb_release_workfn); |
| 566 | set_bit(WB_registered, &wb->state); |
| 567 | |
| 568 | /* |
| 569 | * The root wb determines the registered state of the whole bdi and |
| 570 | * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate |
| 571 | * whether they're still online. Don't link @wb if any is dead. |
| 572 | * See wb_memcg_offline() and wb_blkcg_offline(). |
| 573 | */ |
| 574 | ret = -ENODEV; |
| 575 | spin_lock_irqsave(&cgwb_lock, flags); |
| 576 | if (test_bit(WB_registered, &bdi->wb.state) && |
| 577 | blkcg_cgwb_list->next && memcg_cgwb_list->next) { |
| 578 | /* we might have raced another instance of this function */ |
| 579 | ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb); |
| 580 | if (!ret) { |
| 581 | atomic_inc(&bdi->usage_cnt); |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 582 | list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 583 | list_add(&wb->memcg_node, memcg_cgwb_list); |
| 584 | list_add(&wb->blkcg_node, blkcg_cgwb_list); |
| 585 | css_get(memcg_css); |
| 586 | css_get(blkcg_css); |
| 587 | } |
| 588 | } |
| 589 | spin_unlock_irqrestore(&cgwb_lock, flags); |
| 590 | if (ret) { |
| 591 | if (ret == -EEXIST) |
| 592 | ret = 0; |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 593 | goto err_fprop_exit; |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 594 | } |
| 595 | goto out_put; |
| 596 | |
Tejun Heo | 841710a | 2015-05-22 18:23:33 -0400 | [diff] [blame] | 597 | err_fprop_exit: |
| 598 | fprop_local_destroy_percpu(&wb->memcg_completions); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 599 | err_ref_exit: |
| 600 | percpu_ref_exit(&wb->refcnt); |
| 601 | err_wb_exit: |
| 602 | wb_exit(wb); |
| 603 | err_free: |
| 604 | kfree(wb); |
| 605 | out_put: |
| 606 | css_put(blkcg_css); |
| 607 | return ret; |
| 608 | } |
| 609 | |
| 610 | /** |
| 611 | * wb_get_create - get wb for a given memcg, create if necessary |
| 612 | * @bdi: target bdi |
| 613 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) |
| 614 | * @gfp: allocation mask to use |
| 615 | * |
| 616 | * Try to get the wb for @memcg_css on @bdi. If it doesn't exist, try to |
| 617 | * create one. The returned wb has its refcount incremented. |
| 618 | * |
| 619 | * This function uses css_get() on @memcg_css and thus expects its refcnt |
| 620 | * to be positive on invocation. IOW, rcu_read_lock() protection on |
| 621 | * @memcg_css isn't enough. try_get it before calling this function. |
| 622 | * |
| 623 | * A wb is keyed by its associated memcg. As blkcg implicitly enables |
| 624 | * memcg on the default hierarchy, memcg association is guaranteed to be |
| 625 | * more specific (equal or descendant to the associated blkcg) and thus can |
| 626 | * identify both the memcg and blkcg associations. |
| 627 | * |
| 628 | * Because the blkcg associated with a memcg may change as blkcg is enabled |
| 629 | * and disabled closer to root in the hierarchy, each wb keeps track of |
| 630 | * both the memcg and blkcg associated with it and verifies the blkcg on |
| 631 | * each lookup. On mismatch, the existing wb is discarded and a new one is |
| 632 | * created. |
| 633 | */ |
| 634 | struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, |
| 635 | struct cgroup_subsys_state *memcg_css, |
| 636 | gfp_t gfp) |
| 637 | { |
| 638 | struct bdi_writeback *wb; |
| 639 | |
Mel Gorman | d0164ad | 2015-11-06 16:28:21 -0800 | [diff] [blame] | 640 | might_sleep_if(gfpflags_allow_blocking(gfp)); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 641 | |
| 642 | if (!memcg_css->parent) |
| 643 | return &bdi->wb; |
| 644 | |
| 645 | do { |
| 646 | rcu_read_lock(); |
| 647 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); |
| 648 | if (wb) { |
| 649 | struct cgroup_subsys_state *blkcg_css; |
| 650 | |
| 651 | /* see whether the blkcg association has changed */ |
| 652 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, |
Tejun Heo | c165b3e | 2015-08-18 14:55:29 -0700 | [diff] [blame] | 653 | &io_cgrp_subsys); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 654 | if (unlikely(wb->blkcg_css != blkcg_css || |
| 655 | !wb_tryget(wb))) |
| 656 | wb = NULL; |
| 657 | css_put(blkcg_css); |
| 658 | } |
| 659 | rcu_read_unlock(); |
| 660 | } while (!wb && !cgwb_create(bdi, memcg_css, gfp)); |
| 661 | |
| 662 | return wb; |
| 663 | } |
| 664 | |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 665 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 666 | { |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 667 | int ret; |
| 668 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 669 | INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC); |
| 670 | bdi->cgwb_congested_tree = RB_ROOT; |
| 671 | atomic_set(&bdi->usage_cnt, 1); |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 672 | |
| 673 | ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL); |
| 674 | if (!ret) { |
Johannes Weiner | 7d82860 | 2016-01-14 15:20:56 -0800 | [diff] [blame] | 675 | bdi->wb.memcg_css = &root_mem_cgroup->css; |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 676 | bdi->wb.blkcg_css = blkcg_root_css; |
| 677 | } |
| 678 | return ret; |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 679 | } |
| 680 | |
| 681 | static void cgwb_bdi_destroy(struct backing_dev_info *bdi) |
| 682 | { |
| 683 | struct radix_tree_iter iter; |
Tejun Heo | e27c5b9 | 2015-10-13 18:14:19 -0400 | [diff] [blame] | 684 | struct rb_node *rbn; |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 685 | void **slot; |
| 686 | |
| 687 | WARN_ON(test_bit(WB_registered, &bdi->wb.state)); |
| 688 | |
| 689 | spin_lock_irq(&cgwb_lock); |
Tejun Heo | a20135f | 2015-07-01 20:53:37 -0400 | [diff] [blame] | 690 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 691 | radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0) |
| 692 | cgwb_kill(*slot); |
Tejun Heo | a20135f | 2015-07-01 20:53:37 -0400 | [diff] [blame] | 693 | |
Tejun Heo | e27c5b9 | 2015-10-13 18:14:19 -0400 | [diff] [blame] | 694 | while ((rbn = rb_first(&bdi->cgwb_congested_tree))) { |
| 695 | struct bdi_writeback_congested *congested = |
| 696 | rb_entry(rbn, struct bdi_writeback_congested, rb_node); |
| 697 | |
| 698 | rb_erase(rbn, &bdi->cgwb_congested_tree); |
Tejun Heo | a20135f | 2015-07-01 20:53:37 -0400 | [diff] [blame] | 699 | congested->bdi = NULL; /* mark @congested unlinked */ |
| 700 | } |
| 701 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 702 | spin_unlock_irq(&cgwb_lock); |
| 703 | |
| 704 | /* |
| 705 | * All cgwb's and their congested states must be shutdown and |
| 706 | * released before returning. Drain the usage counter to wait for |
| 707 | * all cgwb's and cgwb_congested's ever created on @bdi. |
| 708 | */ |
| 709 | atomic_dec(&bdi->usage_cnt); |
| 710 | wait_event(cgwb_release_wait, !atomic_read(&bdi->usage_cnt)); |
| 711 | } |
| 712 | |
| 713 | /** |
| 714 | * wb_memcg_offline - kill all wb's associated with a memcg being offlined |
| 715 | * @memcg: memcg being offlined |
| 716 | * |
| 717 | * Also prevents creation of any new wb's associated with @memcg. |
| 718 | */ |
| 719 | void wb_memcg_offline(struct mem_cgroup *memcg) |
| 720 | { |
| 721 | LIST_HEAD(to_destroy); |
| 722 | struct list_head *memcg_cgwb_list = mem_cgroup_cgwb_list(memcg); |
| 723 | struct bdi_writeback *wb, *next; |
| 724 | |
| 725 | spin_lock_irq(&cgwb_lock); |
| 726 | list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node) |
| 727 | cgwb_kill(wb); |
| 728 | memcg_cgwb_list->next = NULL; /* prevent new wb's */ |
| 729 | spin_unlock_irq(&cgwb_lock); |
| 730 | } |
| 731 | |
| 732 | /** |
| 733 | * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined |
| 734 | * @blkcg: blkcg being offlined |
| 735 | * |
| 736 | * Also prevents creation of any new wb's associated with @blkcg. |
| 737 | */ |
| 738 | void wb_blkcg_offline(struct blkcg *blkcg) |
| 739 | { |
| 740 | LIST_HEAD(to_destroy); |
| 741 | struct bdi_writeback *wb, *next; |
| 742 | |
| 743 | spin_lock_irq(&cgwb_lock); |
| 744 | list_for_each_entry_safe(wb, next, &blkcg->cgwb_list, blkcg_node) |
| 745 | cgwb_kill(wb); |
| 746 | blkcg->cgwb_list.next = NULL; /* prevent new wb's */ |
| 747 | spin_unlock_irq(&cgwb_lock); |
| 748 | } |
| 749 | |
| 750 | #else /* CONFIG_CGROUP_WRITEBACK */ |
| 751 | |
Tejun Heo | a13f35e | 2015-07-02 08:44:34 -0600 | [diff] [blame] | 752 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
| 753 | { |
| 754 | int err; |
| 755 | |
| 756 | bdi->wb_congested = kzalloc(sizeof(*bdi->wb_congested), GFP_KERNEL); |
| 757 | if (!bdi->wb_congested) |
| 758 | return -ENOMEM; |
| 759 | |
| 760 | err = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL); |
| 761 | if (err) { |
| 762 | kfree(bdi->wb_congested); |
| 763 | return err; |
| 764 | } |
| 765 | return 0; |
| 766 | } |
| 767 | |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 768 | static void cgwb_bdi_destroy(struct backing_dev_info *bdi) { } |
| 769 | |
| 770 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
| 771 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 772 | int bdi_init(struct backing_dev_info *bdi) |
| 773 | { |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 774 | int ret; |
| 775 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 776 | bdi->dev = NULL; |
| 777 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 778 | bdi->min_ratio = 0; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 779 | bdi->max_ratio = 100; |
Jan Kara | eb608e3 | 2012-05-24 18:59:11 +0200 | [diff] [blame] | 780 | bdi->max_prop_frac = FPROP_FRAC_BASE; |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 781 | INIT_LIST_HEAD(&bdi->bdi_list); |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 782 | INIT_LIST_HEAD(&bdi->wb_list); |
Tejun Heo | cc395d7 | 2015-05-22 17:13:58 -0400 | [diff] [blame] | 783 | init_waitqueue_head(&bdi->wb_waitq); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 784 | |
Tejun Heo | b817525 | 2015-10-02 14:47:05 -0400 | [diff] [blame] | 785 | ret = cgwb_bdi_init(bdi); |
| 786 | |
| 787 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); |
| 788 | |
| 789 | return ret; |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 790 | } |
| 791 | EXPORT_SYMBOL(bdi_init); |
| 792 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 793 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| 794 | const char *fmt, ...) |
| 795 | { |
| 796 | va_list args; |
| 797 | struct device *dev; |
| 798 | |
| 799 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
| 800 | return 0; |
| 801 | |
| 802 | va_start(args, fmt); |
| 803 | 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] | 804 | va_end(args); |
| 805 | if (IS_ERR(dev)) |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 806 | return PTR_ERR(dev); |
| 807 | |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 808 | bdi->dev = dev; |
| 809 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 810 | bdi_debug_register(bdi, dev_name(dev)); |
Tejun Heo | 4610007 | 2015-05-22 17:13:31 -0400 | [diff] [blame] | 811 | set_bit(WB_registered, &bdi->wb.state); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 812 | |
| 813 | spin_lock_bh(&bdi_lock); |
| 814 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
| 815 | spin_unlock_bh(&bdi_lock); |
| 816 | |
| 817 | trace_writeback_bdi_register(bdi); |
| 818 | return 0; |
| 819 | } |
| 820 | EXPORT_SYMBOL(bdi_register); |
| 821 | |
| 822 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) |
| 823 | { |
| 824 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); |
| 825 | } |
| 826 | EXPORT_SYMBOL(bdi_register_dev); |
| 827 | |
| 828 | /* |
Tejun Heo | 4610007 | 2015-05-22 17:13:31 -0400 | [diff] [blame] | 829 | * Remove bdi from bdi_list, and ensure that it is no longer visible |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 830 | */ |
Tejun Heo | 4610007 | 2015-05-22 17:13:31 -0400 | [diff] [blame] | 831 | static void bdi_remove_from_list(struct backing_dev_info *bdi) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 832 | { |
Tejun Heo | 4610007 | 2015-05-22 17:13:31 -0400 | [diff] [blame] | 833 | spin_lock_bh(&bdi_lock); |
| 834 | list_del_rcu(&bdi->bdi_list); |
| 835 | spin_unlock_bh(&bdi_lock); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 836 | |
Tejun Heo | 4610007 | 2015-05-22 17:13:31 -0400 | [diff] [blame] | 837 | synchronize_rcu_expedited(); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 838 | } |
| 839 | |
Tejun Heo | b02176f | 2015-09-08 12:20:22 -0400 | [diff] [blame] | 840 | void bdi_unregister(struct backing_dev_info *bdi) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 841 | { |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 842 | /* make sure nobody finds us on the bdi_list anymore */ |
| 843 | bdi_remove_from_list(bdi); |
| 844 | wb_shutdown(&bdi->wb); |
Tejun Heo | 52ebea7 | 2015-05-22 17:13:37 -0400 | [diff] [blame] | 845 | cgwb_bdi_destroy(bdi); |
Rabin Vincent | 7a401a9 | 2011-11-11 13:29:04 +0100 | [diff] [blame] | 846 | |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame] | 847 | if (bdi->dev) { |
| 848 | bdi_debug_unregister(bdi); |
| 849 | device_unregister(bdi->dev); |
| 850 | bdi->dev = NULL; |
| 851 | } |
Tejun Heo | b02176f | 2015-09-08 12:20:22 -0400 | [diff] [blame] | 852 | } |
Christoph Hellwig | c4db59d | 2015-01-20 14:05:00 -0700 | [diff] [blame] | 853 | |
Tejun Heo | b02176f | 2015-09-08 12:20:22 -0400 | [diff] [blame] | 854 | void bdi_exit(struct backing_dev_info *bdi) |
| 855 | { |
| 856 | WARN_ON_ONCE(bdi->dev); |
Tejun Heo | f0054bb | 2015-05-22 17:13:30 -0400 | [diff] [blame] | 857 | wb_exit(&bdi->wb); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 858 | } |
Tejun Heo | b02176f | 2015-09-08 12:20:22 -0400 | [diff] [blame] | 859 | |
| 860 | void bdi_destroy(struct backing_dev_info *bdi) |
| 861 | { |
| 862 | bdi_unregister(bdi); |
| 863 | bdi_exit(bdi); |
| 864 | } |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 865 | EXPORT_SYMBOL(bdi_destroy); |
| 866 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 867 | /* |
| 868 | * For use from filesystems to quickly init and register a bdi associated |
| 869 | * with dirty writeback |
| 870 | */ |
Christoph Hellwig | b4caecd | 2015-01-14 10:42:32 +0100 | [diff] [blame] | 871 | int bdi_setup_and_register(struct backing_dev_info *bdi, char *name) |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 872 | { |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 873 | int err; |
| 874 | |
| 875 | bdi->name = name; |
Christoph Hellwig | b4caecd | 2015-01-14 10:42:32 +0100 | [diff] [blame] | 876 | bdi->capabilities = 0; |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 877 | err = bdi_init(bdi); |
| 878 | if (err) |
| 879 | return err; |
| 880 | |
Kees Cook | 02aa2a3 | 2013-07-03 15:04:56 -0700 | [diff] [blame] | 881 | err = bdi_register(bdi, NULL, "%.28s-%ld", name, |
| 882 | atomic_long_inc_return(&bdi_seq)); |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame] | 883 | if (err) { |
| 884 | bdi_destroy(bdi); |
| 885 | return err; |
| 886 | } |
| 887 | |
| 888 | return 0; |
| 889 | } |
| 890 | EXPORT_SYMBOL(bdi_setup_and_register); |
| 891 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 892 | static wait_queue_head_t congestion_wqh[2] = { |
| 893 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), |
| 894 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) |
| 895 | }; |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 896 | static atomic_t nr_wb_congested[2]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 897 | |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 898 | void clear_wb_congested(struct bdi_writeback_congested *congested, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 899 | { |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 900 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Kaixu Xia | c877ef8 | 2016-03-31 13:19:41 +0000 | [diff] [blame] | 901 | enum wb_congested_state bit; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 902 | |
Tejun Heo | 4452226 | 2015-05-22 17:13:26 -0400 | [diff] [blame] | 903 | bit = sync ? WB_sync_congested : WB_async_congested; |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 904 | if (test_and_clear_bit(bit, &congested->state)) |
| 905 | atomic_dec(&nr_wb_congested[sync]); |
Peter Zijlstra | 4e857c5 | 2014-03-17 18:06:10 +0100 | [diff] [blame] | 906 | smp_mb__after_atomic(); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 907 | if (waitqueue_active(wqh)) |
| 908 | wake_up(wqh); |
| 909 | } |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 910 | EXPORT_SYMBOL(clear_wb_congested); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 911 | |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 912 | void set_wb_congested(struct bdi_writeback_congested *congested, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 913 | { |
Kaixu Xia | c877ef8 | 2016-03-31 13:19:41 +0000 | [diff] [blame] | 914 | enum wb_congested_state bit; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 915 | |
Tejun Heo | 4452226 | 2015-05-22 17:13:26 -0400 | [diff] [blame] | 916 | bit = sync ? WB_sync_congested : WB_async_congested; |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 917 | if (!test_and_set_bit(bit, &congested->state)) |
| 918 | atomic_inc(&nr_wb_congested[sync]); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 919 | } |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 920 | EXPORT_SYMBOL(set_wb_congested); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 921 | |
| 922 | /** |
| 923 | * congestion_wait - wait for a backing_dev to become uncongested |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 924 | * @sync: SYNC or ASYNC IO |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 925 | * @timeout: timeout in jiffies |
| 926 | * |
| 927 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit |
| 928 | * write congestion. If no backing_devs are congested then just wait for the |
| 929 | * next write to be completed. |
| 930 | */ |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 931 | long congestion_wait(int sync, long timeout) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 932 | { |
| 933 | long ret; |
Mel Gorman | 52bb919 | 2010-10-26 14:21:41 -0700 | [diff] [blame] | 934 | unsigned long start = jiffies; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 935 | DEFINE_WAIT(wait); |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 936 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 937 | |
| 938 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 939 | ret = io_schedule_timeout(timeout); |
| 940 | finish_wait(wqh, &wait); |
Mel Gorman | 52bb919 | 2010-10-26 14:21:41 -0700 | [diff] [blame] | 941 | |
| 942 | trace_writeback_congestion_wait(jiffies_to_usecs(timeout), |
| 943 | jiffies_to_usecs(jiffies - start)); |
| 944 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 945 | return ret; |
| 946 | } |
| 947 | EXPORT_SYMBOL(congestion_wait); |
| 948 | |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 949 | /** |
| 950 | * wait_iff_congested - Conditionally wait for a backing_dev to become uncongested or a zone to complete writes |
| 951 | * @zone: A zone to check if it is heavily congested |
| 952 | * @sync: SYNC or ASYNC IO |
| 953 | * @timeout: timeout in jiffies |
| 954 | * |
| 955 | * In the event of a congested backing_dev (any backing_dev) and the given |
| 956 | * @zone has experienced recent congestion, this waits for up to @timeout |
| 957 | * jiffies for either a BDI to exit congestion of the given @sync queue |
| 958 | * or a write to complete. |
| 959 | * |
Michal Hocko | 373ccbe | 2015-12-11 13:40:32 -0800 | [diff] [blame] | 960 | * In the absence of zone congestion, a short sleep or a cond_resched is |
| 961 | * performed to yield the processor and to allow other subsystems to make |
| 962 | * a forward progress. |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 963 | * |
| 964 | * The return value is 0 if the sleep is for the full timeout. Otherwise, |
| 965 | * it is the number of jiffies that were still remaining when the function |
| 966 | * returned. return_value == timeout implies the function did not sleep. |
| 967 | */ |
| 968 | long wait_iff_congested(struct zone *zone, int sync, long timeout) |
| 969 | { |
| 970 | long ret; |
| 971 | unsigned long start = jiffies; |
| 972 | DEFINE_WAIT(wait); |
| 973 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
| 974 | |
| 975 | /* |
| 976 | * If there is no congestion, or heavy congestion is not being |
| 977 | * encountered in the current zone, yield if necessary instead |
| 978 | * of sleeping on the congestion queue |
| 979 | */ |
Tejun Heo | ec8a6f2 | 2015-05-22 17:13:41 -0400 | [diff] [blame] | 980 | if (atomic_read(&nr_wb_congested[sync]) == 0 || |
Johannes Weiner | 5705465 | 2014-10-09 15:28:17 -0700 | [diff] [blame] | 981 | !test_bit(ZONE_CONGESTED, &zone->flags)) { |
Michal Hocko | 373ccbe | 2015-12-11 13:40:32 -0800 | [diff] [blame] | 982 | |
| 983 | /* |
| 984 | * Memory allocation/reclaim might be called from a WQ |
| 985 | * context and the current implementation of the WQ |
| 986 | * concurrency control doesn't recognize that a particular |
| 987 | * WQ is congested if the worker thread is looping without |
| 988 | * ever sleeping. Therefore we have to do a short sleep |
| 989 | * here rather than calling cond_resched(). |
| 990 | */ |
| 991 | if (current->flags & PF_WQ_WORKER) |
Tetsuo Handa | 564e81a | 2016-02-05 15:36:30 -0800 | [diff] [blame] | 992 | schedule_timeout_uninterruptible(1); |
Michal Hocko | 373ccbe | 2015-12-11 13:40:32 -0800 | [diff] [blame] | 993 | else |
| 994 | cond_resched(); |
Mel Gorman | 0e093d99 | 2010-10-26 14:21:45 -0700 | [diff] [blame] | 995 | |
| 996 | /* In case we scheduled, work out time remaining */ |
| 997 | ret = timeout - (jiffies - start); |
| 998 | if (ret < 0) |
| 999 | ret = 0; |
| 1000 | |
| 1001 | goto out; |
| 1002 | } |
| 1003 | |
| 1004 | /* Sleep until uncongested or a write happens */ |
| 1005 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 1006 | ret = io_schedule_timeout(timeout); |
| 1007 | finish_wait(wqh, &wait); |
| 1008 | |
| 1009 | out: |
| 1010 | trace_writeback_wait_iff_congested(jiffies_to_usecs(timeout), |
| 1011 | jiffies_to_usecs(jiffies - start)); |
| 1012 | |
| 1013 | return ret; |
| 1014 | } |
| 1015 | EXPORT_SYMBOL(wait_iff_congested); |
Wanpeng Li | 3965c9a | 2012-07-31 16:41:52 -0700 | [diff] [blame] | 1016 | |
| 1017 | int pdflush_proc_obsolete(struct ctl_table *table, int write, |
| 1018 | void __user *buffer, size_t *lenp, loff_t *ppos) |
| 1019 | { |
| 1020 | char kbuf[] = "0\n"; |
| 1021 | |
Chen Gang | 4c3bffc | 2013-09-11 14:22:44 -0700 | [diff] [blame] | 1022 | if (*ppos || *lenp < sizeof(kbuf)) { |
Wanpeng Li | 3965c9a | 2012-07-31 16:41:52 -0700 | [diff] [blame] | 1023 | *lenp = 0; |
| 1024 | return 0; |
| 1025 | } |
| 1026 | |
| 1027 | if (copy_to_user(buffer, kbuf, sizeof(kbuf))) |
| 1028 | return -EFAULT; |
Joe Perches | 1170532 | 2016-03-17 14:19:50 -0700 | [diff] [blame] | 1029 | pr_warn_once("%s exported in /proc is scheduled for removal\n", |
| 1030 | table->procname); |
Wanpeng Li | 3965c9a | 2012-07-31 16:41:52 -0700 | [diff] [blame] | 1031 | |
| 1032 | *lenp = 2; |
| 1033 | *ppos += *lenp; |
| 1034 | return 2; |
| 1035 | } |