git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/rebalance.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "bcachefs.h"
   4 #include "alloc_foreground.h"
   5 #include "btree_iter.h"
   6 #include "buckets.h"
   7 #include "clock.h"
   8 #include "disk_groups.h"
   9 #include "extents.h"
  10 #include "io.h"
  11 #include "move.h"
  12 #include "rebalance.h"
  13 #include "super-io.h"
  14
  15 #include <linux/freezer.h>
  16 #include <linux/kthread.h>
  17 #include <linux/sched/cputime.h>
  18 #include <trace/events/bcachefs.h>
  19
  20 static inline bool rebalance_ptr_pred(struct bch_fs *c,
  21                                       struct extent_ptr_decoded p,
  22                                       struct bch_io_opts *io_opts)
  23 {
  24         if (io_opts->background_target &&
  25             !bch2_dev_in_target(c, p.ptr.dev, io_opts->background_target) &&
  26             !p.ptr.cached)
  27                 return true;
  28
  29         if (io_opts->background_compression &&
  30             p.crc.compression_type !=
  31             bch2_compression_opt_to_type[io_opts->background_compression])
  32                 return true;
  33
  34         return false;
  35 }
  36
  37 void bch2_rebalance_add_key(struct bch_fs *c,
  38                             struct bkey_s_c k,
  39                             struct bch_io_opts *io_opts)
  40 {
  41         const union bch_extent_entry *entry;
  42         struct extent_ptr_decoded p;
  43         struct bkey_s_c_extent e;
  44
  45         if (!bkey_extent_is_data(k.k))
  46                 return;
  47
  48         if (!io_opts->background_target &&
  49             !io_opts->background_compression)
  50                 return;
  51
  52         e = bkey_s_c_to_extent(k);
  53
  54         extent_for_each_ptr_decode(e, p, entry)
  55                 if (rebalance_ptr_pred(c, p, io_opts)) {
  56                         struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
  57
  58                         if (atomic64_add_return(p.crc.compressed_size,
  59                                                 &ca->rebalance_work) ==
  60                             p.crc.compressed_size)
  61                                 rebalance_wakeup(c);
  62                 }
  63 }
  64
  65 void bch2_rebalance_add_work(struct bch_fs *c, u64 sectors)
  66 {
  67         if (atomic64_add_return(sectors, &c->rebalance.work_unknown_dev) ==
  68             sectors)
  69                 rebalance_wakeup(c);
  70 }
  71
  72 static enum data_cmd rebalance_pred(struct bch_fs *c, void *arg,
  73                                     struct bkey_s_c k,
  74                                     struct bch_io_opts *io_opts,
  75                                     struct data_opts *data_opts)
  76 {
  77         switch (k.k->type) {
  78         case KEY_TYPE_extent: {
  79                 struct bkey_s_c_extent e = bkey_s_c_to_extent(k);
  80                 const union bch_extent_entry *entry;
  81                 struct extent_ptr_decoded p;
  82
  83                 /* Make sure we have room to add a new pointer: */
  84                 if (bkey_val_u64s(e.k) + BKEY_EXTENT_PTR_U64s_MAX >
  85                     BKEY_EXTENT_VAL_U64s_MAX)
  86                         return DATA_SKIP;
  87
  88                 extent_for_each_ptr_decode(e, p, entry)
  89                         if (rebalance_ptr_pred(c, p, io_opts))
  90                                 goto found;
  91
  92                 return DATA_SKIP;
  93 found:
  94                 data_opts->target               = io_opts->background_target;
  95                 data_opts->btree_insert_flags   = 0;
  96                 return DATA_ADD_REPLICAS;
  97         }
  98         default:
  99                 return DATA_SKIP;
 100         }
 101 }
 102
 103 struct rebalance_work {
 104         int             dev_most_full_idx;
 105         unsigned        dev_most_full_percent;
 106         u64             dev_most_full_work;
 107         u64             dev_most_full_capacity;
 108         u64             total_work;
 109 };
 110
 111 static void rebalance_work_accumulate(struct rebalance_work *w,
 112                 u64 dev_work, u64 unknown_dev, u64 capacity, int idx)
 113 {
 114         unsigned percent_full;
 115         u64 work = dev_work + unknown_dev;
 116
 117         if (work < dev_work || work < unknown_dev)
 118                 work = U64_MAX;
 119         work = min(work, capacity);
 120
 121         percent_full = div64_u64(work * 100, capacity);
 122
 123         if (percent_full >= w->dev_most_full_percent) {
 124                 w->dev_most_full_idx            = idx;
 125                 w->dev_most_full_percent        = percent_full;
 126                 w->dev_most_full_work           = work;
 127                 w->dev_most_full_capacity       = capacity;
 128         }
 129
 130         if (w->total_work + dev_work >= w->total_work &&
 131             w->total_work + dev_work >= dev_work)
 132                 w->total_work += dev_work;
 133 }
 134
 135 static struct rebalance_work rebalance_work(struct bch_fs *c)
 136 {
 137         struct bch_dev *ca;
 138         struct rebalance_work ret = { .dev_most_full_idx = -1 };
 139         u64 unknown_dev = atomic64_read(&c->rebalance.work_unknown_dev);
 140         unsigned i;
 141
 142         for_each_online_member(ca, c, i)
 143                 rebalance_work_accumulate(&ret,
 144                         atomic64_read(&ca->rebalance_work),
 145                         unknown_dev,
 146                         bucket_to_sector(ca, ca->mi.nbuckets -
 147                                          ca->mi.first_bucket),
 148                         i);
 149
 150         rebalance_work_accumulate(&ret,
 151                 unknown_dev, 0, c->capacity, -1);
 152
 153         return ret;
 154 }
 155
 156 static void rebalance_work_reset(struct bch_fs *c)
 157 {
 158         struct bch_dev *ca;
 159         unsigned i;
 160
 161         for_each_online_member(ca, c, i)
 162                 atomic64_set(&ca->rebalance_work, 0);
 163
 164         atomic64_set(&c->rebalance.work_unknown_dev, 0);
 165 }
 166
 167 static unsigned long curr_cputime(void)
 168 {
 169         u64 utime, stime;
 170
 171         task_cputime_adjusted(current, &utime, &stime);
 172         return nsecs_to_jiffies(utime + stime);
 173 }
 174
 175 static int bch2_rebalance_thread(void *arg)
 176 {
 177         struct bch_fs *c = arg;
 178         struct bch_fs_rebalance *r = &c->rebalance;
 179         struct io_clock *clock = &c->io_clock[WRITE];
 180         struct rebalance_work w, p;
 181         unsigned long start, prev_start;
 182         unsigned long prev_run_time, prev_run_cputime;
 183         unsigned long cputime, prev_cputime;
 184         unsigned long io_start;
 185         long throttle;
 186
 187         set_freezable();
 188
 189         io_start        = atomic_long_read(&clock->now);
 190         p               = rebalance_work(c);
 191         prev_start      = jiffies;
 192         prev_cputime    = curr_cputime();
 193
 194         while (!kthread_wait_freezable(r->enabled)) {
 195                 start                   = jiffies;
 196                 cputime                 = curr_cputime();
 197
 198                 prev_run_time           = start - prev_start;
 199                 prev_run_cputime        = cputime - prev_cputime;
 200
 201                 w                       = rebalance_work(c);
 202                 BUG_ON(!w.dev_most_full_capacity);
 203
 204                 if (!w.total_work) {
 205                         r->state = REBALANCE_WAITING;
 206                         kthread_wait_freezable(rebalance_work(c).total_work);
 207                         continue;
 208                 }
 209
 210                 /*
 211                  * If there isn't much work to do, throttle cpu usage:
 212                  */
 213                 throttle = prev_run_cputime * 100 /
 214                         max(1U, w.dev_most_full_percent) -
 215                         prev_run_time;
 216
 217                 if (w.dev_most_full_percent < 20 && throttle > 0) {
 218                         r->state = REBALANCE_THROTTLED;
 219                         r->throttled_until_iotime = io_start +
 220                                 div_u64(w.dev_most_full_capacity *
 221                                         (20 - w.dev_most_full_percent),
 222                                         50);
 223                         r->throttled_until_cputime = start + throttle;
 224
 225                         bch2_kthread_io_clock_wait(clock,
 226                                 r->throttled_until_iotime,
 227                                 throttle);
 228                         continue;
 229                 }
 230
 231                 /* minimum 1 mb/sec: */
 232                 r->pd.rate.rate =
 233                         max_t(u64, 1 << 11,
 234                               r->pd.rate.rate *
 235                               max(p.dev_most_full_percent, 1U) /
 236                               max(w.dev_most_full_percent, 1U));
 237
 238                 io_start        = atomic_long_read(&clock->now);
 239                 p               = w;
 240                 prev_start      = start;
 241                 prev_cputime    = cputime;
 242
 243                 r->state = REBALANCE_RUNNING;
 244                 memset(&r->move_stats, 0, sizeof(r->move_stats));
 245                 rebalance_work_reset(c);
 246
 247                 bch2_move_data(c,
 248                                /* ratelimiting disabled for now */
 249                                NULL, /*  &r->pd.rate, */
 250                                writepoint_ptr(&c->rebalance_write_point),
 251                                POS_MIN, POS_MAX,
 252                                rebalance_pred, NULL,
 253                                &r->move_stats);
 254         }
 255
 256         return 0;
 257 }
 258
 259 ssize_t bch2_rebalance_work_show(struct bch_fs *c, char *buf)
 260 {
 261         struct printbuf out = _PBUF(buf, PAGE_SIZE);
 262         struct bch_fs_rebalance *r = &c->rebalance;
 263         struct rebalance_work w = rebalance_work(c);
 264         char h1[21], h2[21];
 265
 266         bch2_hprint(&PBUF(h1), w.dev_most_full_work << 9);
 267         bch2_hprint(&PBUF(h2), w.dev_most_full_capacity << 9);
 268         pr_buf(&out, "fullest_dev (%i):\t%s/%s\n",
 269                w.dev_most_full_idx, h1, h2);
 270
 271         bch2_hprint(&PBUF(h1), w.total_work << 9);
 272         bch2_hprint(&PBUF(h2), c->capacity << 9);
 273         pr_buf(&out, "total work:\t\t%s/%s\n", h1, h2);
 274
 275         pr_buf(&out, "rate:\t\t\t%u\n", r->pd.rate.rate);
 276
 277         switch (r->state) {
 278         case REBALANCE_WAITING:
 279                 pr_buf(&out, "waiting\n");
 280                 break;
 281         case REBALANCE_THROTTLED:
 282                 bch2_hprint(&PBUF(h1),
 283                             (r->throttled_until_iotime -
 284                              atomic_long_read(&c->io_clock[WRITE].now)) << 9);
 285                 pr_buf(&out, "throttled for %lu sec or %s io\n",
 286                        (r->throttled_until_cputime - jiffies) / HZ,
 287                        h1);
 288                 break;
 289         case REBALANCE_RUNNING:
 290                 pr_buf(&out, "running\n");
 291                 pr_buf(&out, "pos %llu:%llu\n",
 292                        r->move_stats.pos.inode,
 293                        r->move_stats.pos.offset);
 294                 break;
 295         }
 296
 297         return out.pos - buf;
 298 }
 299
 300 void bch2_rebalance_stop(struct bch_fs *c)
 301 {
 302         struct task_struct *p;
 303
 304         c->rebalance.pd.rate.rate = UINT_MAX;
 305         bch2_ratelimit_reset(&c->rebalance.pd.rate);
 306
 307         p = rcu_dereference_protected(c->rebalance.thread, 1);
 308         c->rebalance.thread = NULL;
 309
 310         if (p) {
 311                 /* for sychronizing with rebalance_wakeup() */
 312                 synchronize_rcu();
 313
 314                 kthread_stop(p);
 315                 put_task_struct(p);
 316         }
 317 }
 318
 319 int bch2_rebalance_start(struct bch_fs *c)
 320 {
 321         struct task_struct *p;
 322
 323         if (c->opts.nochanges)
 324                 return 0;
 325
 326         p = kthread_create(bch2_rebalance_thread, c, "bch_rebalance");
 327         if (IS_ERR(p))
 328                 return PTR_ERR(p);
 329
 330         get_task_struct(p);
 331         rcu_assign_pointer(c->rebalance.thread, p);
 332         wake_up_process(p);
 333         return 0;
 334 }
 335
 336 void bch2_fs_rebalance_init(struct bch_fs *c)
 337 {
 338         bch2_pd_controller_init(&c->rebalance.pd);
 339
 340         atomic64_set(&c->rebalance.work_unknown_dev, S64_MAX);
 341 }