1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Moving/copying garbage collector 4 * 5 * Copyright 2012 Google, Inc. 6 */ 7 8 #include "bcachefs.h" 9 #include "alloc_background.h" 10 #include "alloc_foreground.h" 11 #include "btree_iter.h" 12 #include "btree_update.h" 13 #include "btree_write_buffer.h" 14 #include "buckets.h" 15 #include "clock.h" 16 #include "errcode.h" 17 #include "error.h" 18 #include "lru.h" 19 #include "move.h" 20 #include "movinggc.h" 21 #include "trace.h" 22 23 #include <linux/freezer.h> 24 #include <linux/kthread.h> 25 #include <linux/math64.h> 26 #include <linux/sched/task.h> 27 #include <linux/wait.h> 28 29 struct buckets_in_flight { 30 struct rhashtable table; 31 struct move_bucket_in_flight *first; 32 struct move_bucket_in_flight *last; 33 size_t nr; 34 size_t sectors; 35 }; 36 37 static const struct rhashtable_params bch_move_bucket_params = { 38 .head_offset = offsetof(struct move_bucket_in_flight, hash), 39 .key_offset = offsetof(struct move_bucket_in_flight, bucket.k), 40 .key_len = sizeof(struct move_bucket_key), 41 }; 42 43 static struct move_bucket_in_flight * 44 move_bucket_in_flight_add(struct buckets_in_flight *list, struct move_bucket b) 45 { 46 struct move_bucket_in_flight *new = kzalloc(sizeof(*new), GFP_KERNEL); 47 int ret; 48 49 if (!new) 50 return ERR_PTR(-ENOMEM); 51 52 new->bucket = b; 53 54 ret = rhashtable_lookup_insert_fast(&list->table, &new->hash, 55 bch_move_bucket_params); 56 if (ret) { 57 kfree(new); 58 return ERR_PTR(ret); 59 } 60 61 if (!list->first) 62 list->first = new; 63 else 64 list->last->next = new; 65 66 list->last = new; 67 list->nr++; 68 list->sectors += b.sectors; 69 return new; 70 } 71 72 static int bch2_bucket_is_movable(struct btree_trans *trans, 73 struct move_bucket *b, u64 time) 74 { 75 struct btree_iter iter; 76 struct bkey_s_c k; 77 struct bch_alloc_v4 _a; 78 const struct bch_alloc_v4 *a; 79 int ret; 80 81 if (bch2_bucket_is_open(trans->c, 82 b->k.bucket.inode, 83 b->k.bucket.offset)) 84 return 0; 85 86 k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc, 87 b->k.bucket, BTREE_ITER_CACHED); 88 ret = bkey_err(k); 89 if (ret) 90 return ret; 91 92 a = bch2_alloc_to_v4(k, &_a); 93 b->k.gen = a->gen; 94 b->sectors = a->dirty_sectors; 95 96 ret = data_type_movable(a->data_type) && 97 a->fragmentation_lru && 98 a->fragmentation_lru <= time; 99 100 bch2_trans_iter_exit(trans, &iter); 101 return ret; 102 } 103 104 static void move_buckets_wait(struct moving_context *ctxt, 105 struct buckets_in_flight *list, 106 bool flush) 107 { 108 struct move_bucket_in_flight *i; 109 int ret; 110 111 while ((i = list->first)) { 112 if (flush) 113 move_ctxt_wait_event(ctxt, !atomic_read(&i->count)); 114 115 if (atomic_read(&i->count)) 116 break; 117 118 list->first = i->next; 119 if (!list->first) 120 list->last = NULL; 121 122 list->nr--; 123 list->sectors -= i->bucket.sectors; 124 125 ret = rhashtable_remove_fast(&list->table, &i->hash, 126 bch_move_bucket_params); 127 BUG_ON(ret); 128 kfree(i); 129 } 130 131 bch2_trans_unlock_long(ctxt->trans); 132 } 133 134 static bool bucket_in_flight(struct buckets_in_flight *list, 135 struct move_bucket_key k) 136 { 137 return rhashtable_lookup_fast(&list->table, &k, bch_move_bucket_params); 138 } 139 140 typedef DARRAY(struct move_bucket) move_buckets; 141 142 static int bch2_copygc_get_buckets(struct moving_context *ctxt, 143 struct buckets_in_flight *buckets_in_flight, 144 move_buckets *buckets) 145 { 146 struct btree_trans *trans = ctxt->trans; 147 struct bch_fs *c = trans->c; 148 struct btree_iter iter; 149 struct bkey_s_c k; 150 size_t nr_to_get = max_t(size_t, 16U, buckets_in_flight->nr / 4); 151 size_t saw = 0, in_flight = 0, not_movable = 0, sectors = 0; 152 int ret; 153 154 move_buckets_wait(ctxt, buckets_in_flight, false); 155 156 ret = bch2_btree_write_buffer_flush(trans); 157 if (bch2_fs_fatal_err_on(ret, c, "%s: error %s from bch2_btree_write_buffer_flush()", 158 __func__, bch2_err_str(ret))) 159 return ret; 160 161 ret = for_each_btree_key2_upto(trans, iter, BTREE_ID_lru, 162 lru_pos(BCH_LRU_FRAGMENTATION_START, 0, 0), 163 lru_pos(BCH_LRU_FRAGMENTATION_START, U64_MAX, LRU_TIME_MAX), 164 0, k, ({ 165 struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) }; 166 int ret2 = 0; 167 168 saw++; 169 170 if (!bch2_bucket_is_movable(trans, &b, lru_pos_time(k.k->p))) 171 not_movable++; 172 else if (bucket_in_flight(buckets_in_flight, b.k)) 173 in_flight++; 174 else { 175 ret2 = darray_push(buckets, b) ?: buckets->nr >= nr_to_get; 176 if (ret2 >= 0) 177 sectors += b.sectors; 178 } 179 ret2; 180 })); 181 182 pr_debug("have: %zu (%zu) saw %zu in flight %zu not movable %zu got %zu (%zu)/%zu buckets ret %i", 183 buckets_in_flight->nr, buckets_in_flight->sectors, 184 saw, in_flight, not_movable, buckets->nr, sectors, nr_to_get, ret); 185 186 return ret < 0 ? ret : 0; 187 } 188 189 noinline 190 static int bch2_copygc(struct moving_context *ctxt, 191 struct buckets_in_flight *buckets_in_flight, 192 bool *did_work) 193 { 194 struct btree_trans *trans = ctxt->trans; 195 struct bch_fs *c = trans->c; 196 struct data_update_opts data_opts = { 197 .btree_insert_flags = BCH_WATERMARK_copygc, 198 }; 199 move_buckets buckets = { 0 }; 200 struct move_bucket_in_flight *f; 201 struct move_bucket *i; 202 u64 moved = atomic64_read(&ctxt->stats->sectors_moved); 203 int ret = 0; 204 205 ret = bch2_copygc_get_buckets(ctxt, buckets_in_flight, &buckets); 206 if (ret) 207 goto err; 208 209 darray_for_each(buckets, i) { 210 if (unlikely(freezing(current))) 211 break; 212 213 f = move_bucket_in_flight_add(buckets_in_flight, *i); 214 ret = PTR_ERR_OR_ZERO(f); 215 if (ret == -EEXIST) { /* rare race: copygc_get_buckets returned same bucket more than once */ 216 ret = 0; 217 continue; 218 } 219 if (ret == -ENOMEM) { /* flush IO, continue later */ 220 ret = 0; 221 break; 222 } 223 224 ret = __bch2_evacuate_bucket(ctxt, f, f->bucket.k.bucket, 225 f->bucket.k.gen, data_opts); 226 if (ret) 227 goto err; 228 229 *did_work = true; 230 } 231 err: 232 darray_exit(&buckets); 233 234 /* no entries in LRU btree found, or got to end: */ 235 if (bch2_err_matches(ret, ENOENT)) 236 ret = 0; 237 238 if (ret < 0 && !bch2_err_matches(ret, EROFS)) 239 bch_err_msg(c, ret, "from bch2_move_data()"); 240 241 moved = atomic64_read(&ctxt->stats->sectors_moved) - moved; 242 trace_and_count(c, copygc, c, moved, 0, 0, 0); 243 return ret; 244 } 245 246 /* 247 * Copygc runs when the amount of fragmented data is above some arbitrary 248 * threshold: 249 * 250 * The threshold at the limit - when the device is full - is the amount of space 251 * we reserved in bch2_recalc_capacity; we can't have more than that amount of 252 * disk space stranded due to fragmentation and store everything we have 253 * promised to store. 254 * 255 * But we don't want to be running copygc unnecessarily when the device still 256 * has plenty of free space - rather, we want copygc to smoothly run every so 257 * often and continually reduce the amount of fragmented space as the device 258 * fills up. So, we increase the threshold by half the current free space. 259 */ 260 unsigned long bch2_copygc_wait_amount(struct bch_fs *c) 261 { 262 struct bch_dev *ca; 263 unsigned dev_idx; 264 s64 wait = S64_MAX, fragmented_allowed, fragmented; 265 unsigned i; 266 267 for_each_rw_member(ca, c, dev_idx) { 268 struct bch_dev_usage usage = bch2_dev_usage_read(ca); 269 270 fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) * 271 ca->mi.bucket_size) >> 1); 272 fragmented = 0; 273 274 for (i = 0; i < BCH_DATA_NR; i++) 275 if (data_type_movable(i)) 276 fragmented += usage.d[i].fragmented; 277 278 wait = min(wait, max(0LL, fragmented_allowed - fragmented)); 279 } 280 281 return wait; 282 } 283 284 void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c) 285 { 286 prt_printf(out, "Currently waiting for: "); 287 prt_human_readable_u64(out, max(0LL, c->copygc_wait - 288 atomic64_read(&c->io_clock[WRITE].now)) << 9); 289 prt_newline(out); 290 291 prt_printf(out, "Currently waiting since: "); 292 prt_human_readable_u64(out, max(0LL, 293 atomic64_read(&c->io_clock[WRITE].now) - 294 c->copygc_wait_at) << 9); 295 prt_newline(out); 296 297 prt_printf(out, "Currently calculated wait: "); 298 prt_human_readable_u64(out, bch2_copygc_wait_amount(c)); 299 prt_newline(out); 300 } 301 302 static int bch2_copygc_thread(void *arg) 303 { 304 struct bch_fs *c = arg; 305 struct moving_context ctxt; 306 struct bch_move_stats move_stats; 307 struct io_clock *clock = &c->io_clock[WRITE]; 308 struct buckets_in_flight *buckets; 309 u64 last, wait; 310 int ret = 0; 311 312 buckets = kzalloc(sizeof(struct buckets_in_flight), GFP_KERNEL); 313 if (!buckets) 314 return -ENOMEM; 315 ret = rhashtable_init(&buckets->table, &bch_move_bucket_params); 316 if (ret) { 317 kfree(buckets); 318 bch_err_msg(c, ret, "allocating copygc buckets in flight"); 319 return ret; 320 } 321 322 set_freezable(); 323 324 bch2_move_stats_init(&move_stats, "copygc"); 325 bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats, 326 writepoint_ptr(&c->copygc_write_point), 327 false); 328 329 while (!ret && !kthread_should_stop()) { 330 bool did_work = false; 331 332 bch2_trans_unlock_long(ctxt.trans); 333 cond_resched(); 334 335 if (!c->copy_gc_enabled) { 336 move_buckets_wait(&ctxt, buckets, true); 337 kthread_wait_freezable(c->copy_gc_enabled); 338 } 339 340 if (unlikely(freezing(current))) { 341 move_buckets_wait(&ctxt, buckets, true); 342 __refrigerator(false); 343 continue; 344 } 345 346 last = atomic64_read(&clock->now); 347 wait = bch2_copygc_wait_amount(c); 348 349 if (wait > clock->max_slop) { 350 c->copygc_wait_at = last; 351 c->copygc_wait = last + wait; 352 move_buckets_wait(&ctxt, buckets, true); 353 trace_and_count(c, copygc_wait, c, wait, last + wait); 354 bch2_kthread_io_clock_wait(clock, last + wait, 355 MAX_SCHEDULE_TIMEOUT); 356 continue; 357 } 358 359 c->copygc_wait = 0; 360 361 c->copygc_running = true; 362 ret = bch2_copygc(&ctxt, buckets, &did_work); 363 c->copygc_running = false; 364 365 wake_up(&c->copygc_running_wq); 366 367 if (!wait && !did_work) { 368 u64 min_member_capacity = bch2_min_rw_member_capacity(c); 369 370 if (min_member_capacity == U64_MAX) 371 min_member_capacity = 128 * 2048; 372 373 bch2_trans_unlock_long(ctxt.trans); 374 bch2_kthread_io_clock_wait(clock, last + (min_member_capacity >> 6), 375 MAX_SCHEDULE_TIMEOUT); 376 } 377 } 378 379 move_buckets_wait(&ctxt, buckets, true); 380 381 rhashtable_destroy(&buckets->table); 382 kfree(buckets); 383 bch2_moving_ctxt_exit(&ctxt); 384 bch2_move_stats_exit(&move_stats, c); 385 386 return 0; 387 } 388 389 void bch2_copygc_stop(struct bch_fs *c) 390 { 391 if (c->copygc_thread) { 392 kthread_stop(c->copygc_thread); 393 put_task_struct(c->copygc_thread); 394 } 395 c->copygc_thread = NULL; 396 } 397 398 int bch2_copygc_start(struct bch_fs *c) 399 { 400 struct task_struct *t; 401 int ret; 402 403 if (c->copygc_thread) 404 return 0; 405 406 if (c->opts.nochanges) 407 return 0; 408 409 if (bch2_fs_init_fault("copygc_start")) 410 return -ENOMEM; 411 412 t = kthread_create(bch2_copygc_thread, c, "bch-copygc/%s", c->name); 413 ret = PTR_ERR_OR_ZERO(t); 414 if (ret) { 415 bch_err_msg(c, ret, "creating copygc thread"); 416 return ret; 417 } 418 419 get_task_struct(t); 420 421 c->copygc_thread = t; 422 wake_up_process(c->copygc_thread); 423 424 return 0; 425 } 426 427 void bch2_fs_copygc_init(struct bch_fs *c) 428 { 429 init_waitqueue_head(&c->copygc_running_wq); 430 c->copygc_running = false; 431 } 432