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 .automatic_shrinking = true, 42 }; 43 44 static struct move_bucket_in_flight * 45 move_bucket_in_flight_add(struct buckets_in_flight *list, struct move_bucket b) 46 { 47 struct move_bucket_in_flight *new = kzalloc(sizeof(*new), GFP_KERNEL); 48 int ret; 49 50 if (!new) 51 return ERR_PTR(-ENOMEM); 52 53 new->bucket = b; 54 55 ret = rhashtable_lookup_insert_fast(&list->table, &new->hash, 56 bch_move_bucket_params); 57 if (ret) { 58 kfree(new); 59 return ERR_PTR(ret); 60 } 61 62 if (!list->first) 63 list->first = new; 64 else 65 list->last->next = new; 66 67 list->last = new; 68 list->nr++; 69 list->sectors += b.sectors; 70 return new; 71 } 72 73 static int bch2_bucket_is_movable(struct btree_trans *trans, 74 struct move_bucket *b, u64 time) 75 { 76 struct btree_iter iter; 77 struct bkey_s_c k; 78 struct bch_alloc_v4 _a; 79 const struct bch_alloc_v4 *a; 80 int ret; 81 82 if (bch2_bucket_is_open(trans->c, 83 b->k.bucket.inode, 84 b->k.bucket.offset)) 85 return 0; 86 87 k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc, 88 b->k.bucket, BTREE_ITER_cached); 89 ret = bkey_err(k); 90 if (ret) 91 return ret; 92 93 a = bch2_alloc_to_v4(k, &_a); 94 b->k.gen = a->gen; 95 b->sectors = bch2_bucket_sectors_dirty(*a); 96 97 ret = data_type_movable(a->data_type) && 98 a->fragmentation_lru && 99 a->fragmentation_lru <= time; 100 101 bch2_trans_iter_exit(trans, &iter); 102 return ret; 103 } 104 105 static void move_buckets_wait(struct moving_context *ctxt, 106 struct buckets_in_flight *list, 107 bool flush) 108 { 109 struct move_bucket_in_flight *i; 110 int ret; 111 112 while ((i = list->first)) { 113 if (flush) 114 move_ctxt_wait_event(ctxt, !atomic_read(&i->count)); 115 116 if (atomic_read(&i->count)) 117 break; 118 119 list->first = i->next; 120 if (!list->first) 121 list->last = NULL; 122 123 list->nr--; 124 list->sectors -= i->bucket.sectors; 125 126 ret = rhashtable_remove_fast(&list->table, &i->hash, 127 bch_move_bucket_params); 128 BUG_ON(ret); 129 kfree(i); 130 } 131 132 bch2_trans_unlock_long(ctxt->trans); 133 } 134 135 static bool bucket_in_flight(struct buckets_in_flight *list, 136 struct move_bucket_key k) 137 { 138 return rhashtable_lookup_fast(&list->table, &k, bch_move_bucket_params); 139 } 140 141 typedef DARRAY(struct move_bucket) move_buckets; 142 143 static int bch2_copygc_get_buckets(struct moving_context *ctxt, 144 struct buckets_in_flight *buckets_in_flight, 145 move_buckets *buckets) 146 { 147 struct btree_trans *trans = ctxt->trans; 148 struct bch_fs *c = trans->c; 149 size_t nr_to_get = max_t(size_t, 16U, buckets_in_flight->nr / 4); 150 size_t saw = 0, in_flight = 0, not_movable = 0, sectors = 0; 151 int ret; 152 153 move_buckets_wait(ctxt, buckets_in_flight, false); 154 155 ret = bch2_btree_write_buffer_tryflush(trans); 156 if (bch2_err_matches(ret, EROFS)) 157 return ret; 158 159 if (bch2_fs_fatal_err_on(ret, c, "%s: from bch2_btree_write_buffer_tryflush()", bch2_err_str(ret))) 160 return ret; 161 162 bch2_trans_begin(trans); 163 164 ret = for_each_btree_key_upto(trans, iter, BTREE_ID_lru, 165 lru_pos(BCH_LRU_FRAGMENTATION_START, 0, 0), 166 lru_pos(BCH_LRU_FRAGMENTATION_START, U64_MAX, LRU_TIME_MAX), 167 0, k, ({ 168 struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) }; 169 int ret2 = 0; 170 171 saw++; 172 173 ret2 = bch2_bucket_is_movable(trans, &b, lru_pos_time(k.k->p)); 174 if (ret2 < 0) 175 goto err; 176 177 if (!ret2) 178 not_movable++; 179 else if (bucket_in_flight(buckets_in_flight, b.k)) 180 in_flight++; 181 else { 182 ret2 = darray_push(buckets, b); 183 if (ret2) 184 goto err; 185 sectors += b.sectors; 186 } 187 188 ret2 = buckets->nr >= nr_to_get; 189 err: 190 ret2; 191 })); 192 193 pr_debug("have: %zu (%zu) saw %zu in flight %zu not movable %zu got %zu (%zu)/%zu buckets ret %i", 194 buckets_in_flight->nr, buckets_in_flight->sectors, 195 saw, in_flight, not_movable, buckets->nr, sectors, nr_to_get, ret); 196 197 return ret < 0 ? ret : 0; 198 } 199 200 noinline 201 static int bch2_copygc(struct moving_context *ctxt, 202 struct buckets_in_flight *buckets_in_flight, 203 bool *did_work) 204 { 205 struct btree_trans *trans = ctxt->trans; 206 struct bch_fs *c = trans->c; 207 struct data_update_opts data_opts = { 208 .btree_insert_flags = BCH_WATERMARK_copygc, 209 }; 210 move_buckets buckets = { 0 }; 211 struct move_bucket_in_flight *f; 212 u64 moved = atomic64_read(&ctxt->stats->sectors_moved); 213 int ret = 0; 214 215 ret = bch2_copygc_get_buckets(ctxt, buckets_in_flight, &buckets); 216 if (ret) 217 goto err; 218 219 darray_for_each(buckets, i) { 220 if (kthread_should_stop() || freezing(current)) 221 break; 222 223 f = move_bucket_in_flight_add(buckets_in_flight, *i); 224 ret = PTR_ERR_OR_ZERO(f); 225 if (ret == -EEXIST) { /* rare race: copygc_get_buckets returned same bucket more than once */ 226 ret = 0; 227 continue; 228 } 229 if (ret == -ENOMEM) { /* flush IO, continue later */ 230 ret = 0; 231 break; 232 } 233 234 ret = bch2_evacuate_bucket(ctxt, f, f->bucket.k.bucket, 235 f->bucket.k.gen, data_opts); 236 if (ret) 237 goto err; 238 239 *did_work = true; 240 } 241 err: 242 darray_exit(&buckets); 243 244 /* no entries in LRU btree found, or got to end: */ 245 if (bch2_err_matches(ret, ENOENT)) 246 ret = 0; 247 248 if (ret < 0 && !bch2_err_matches(ret, EROFS)) 249 bch_err_msg(c, ret, "from bch2_move_data()"); 250 251 moved = atomic64_read(&ctxt->stats->sectors_moved) - moved; 252 trace_and_count(c, copygc, c, moved, 0, 0, 0); 253 return ret; 254 } 255 256 /* 257 * Copygc runs when the amount of fragmented data is above some arbitrary 258 * threshold: 259 * 260 * The threshold at the limit - when the device is full - is the amount of space 261 * we reserved in bch2_recalc_capacity; we can't have more than that amount of 262 * disk space stranded due to fragmentation and store everything we have 263 * promised to store. 264 * 265 * But we don't want to be running copygc unnecessarily when the device still 266 * has plenty of free space - rather, we want copygc to smoothly run every so 267 * often and continually reduce the amount of fragmented space as the device 268 * fills up. So, we increase the threshold by half the current free space. 269 */ 270 unsigned long bch2_copygc_wait_amount(struct bch_fs *c) 271 { 272 s64 wait = S64_MAX, fragmented_allowed, fragmented; 273 274 for_each_rw_member(c, ca) { 275 struct bch_dev_usage usage = bch2_dev_usage_read(ca); 276 277 fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) * 278 ca->mi.bucket_size) >> 1); 279 fragmented = 0; 280 281 for (unsigned i = 0; i < BCH_DATA_NR; i++) 282 if (data_type_movable(i)) 283 fragmented += usage.d[i].fragmented; 284 285 wait = min(wait, max(0LL, fragmented_allowed - fragmented)); 286 } 287 288 return wait; 289 } 290 291 void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c) 292 { 293 prt_printf(out, "Currently waiting for: "); 294 prt_human_readable_u64(out, max(0LL, c->copygc_wait - 295 atomic64_read(&c->io_clock[WRITE].now)) << 9); 296 prt_newline(out); 297 298 prt_printf(out, "Currently waiting since: "); 299 prt_human_readable_u64(out, max(0LL, 300 atomic64_read(&c->io_clock[WRITE].now) - 301 c->copygc_wait_at) << 9); 302 prt_newline(out); 303 304 prt_printf(out, "Currently calculated wait: "); 305 prt_human_readable_u64(out, bch2_copygc_wait_amount(c)); 306 prt_newline(out); 307 } 308 309 static int bch2_copygc_thread(void *arg) 310 { 311 struct bch_fs *c = arg; 312 struct moving_context ctxt; 313 struct bch_move_stats move_stats; 314 struct io_clock *clock = &c->io_clock[WRITE]; 315 struct buckets_in_flight *buckets; 316 u64 last, wait; 317 int ret = 0; 318 319 buckets = kzalloc(sizeof(struct buckets_in_flight), GFP_KERNEL); 320 if (!buckets) 321 return -ENOMEM; 322 ret = rhashtable_init(&buckets->table, &bch_move_bucket_params); 323 bch_err_msg(c, ret, "allocating copygc buckets in flight"); 324 if (ret) { 325 kfree(buckets); 326 return ret; 327 } 328 329 set_freezable(); 330 331 bch2_move_stats_init(&move_stats, "copygc"); 332 bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats, 333 writepoint_ptr(&c->copygc_write_point), 334 false); 335 336 while (!ret && !kthread_should_stop()) { 337 bool did_work = false; 338 339 bch2_trans_unlock_long(ctxt.trans); 340 cond_resched(); 341 342 if (!c->copy_gc_enabled) { 343 move_buckets_wait(&ctxt, buckets, true); 344 kthread_wait_freezable(c->copy_gc_enabled || 345 kthread_should_stop()); 346 } 347 348 if (unlikely(freezing(current))) { 349 move_buckets_wait(&ctxt, buckets, true); 350 __refrigerator(false); 351 continue; 352 } 353 354 last = atomic64_read(&clock->now); 355 wait = bch2_copygc_wait_amount(c); 356 357 if (wait > clock->max_slop) { 358 c->copygc_wait_at = last; 359 c->copygc_wait = last + wait; 360 move_buckets_wait(&ctxt, buckets, true); 361 trace_and_count(c, copygc_wait, c, wait, last + wait); 362 bch2_kthread_io_clock_wait(clock, last + wait, 363 MAX_SCHEDULE_TIMEOUT); 364 continue; 365 } 366 367 c->copygc_wait = 0; 368 369 c->copygc_running = true; 370 ret = bch2_copygc(&ctxt, buckets, &did_work); 371 c->copygc_running = false; 372 373 wake_up(&c->copygc_running_wq); 374 375 if (!wait && !did_work) { 376 u64 min_member_capacity = bch2_min_rw_member_capacity(c); 377 378 if (min_member_capacity == U64_MAX) 379 min_member_capacity = 128 * 2048; 380 381 bch2_trans_unlock_long(ctxt.trans); 382 bch2_kthread_io_clock_wait(clock, last + (min_member_capacity >> 6), 383 MAX_SCHEDULE_TIMEOUT); 384 } 385 } 386 387 move_buckets_wait(&ctxt, buckets, true); 388 389 rhashtable_destroy(&buckets->table); 390 kfree(buckets); 391 bch2_moving_ctxt_exit(&ctxt); 392 bch2_move_stats_exit(&move_stats, c); 393 394 return 0; 395 } 396 397 void bch2_copygc_stop(struct bch_fs *c) 398 { 399 if (c->copygc_thread) { 400 kthread_stop(c->copygc_thread); 401 put_task_struct(c->copygc_thread); 402 } 403 c->copygc_thread = NULL; 404 } 405 406 int bch2_copygc_start(struct bch_fs *c) 407 { 408 struct task_struct *t; 409 int ret; 410 411 if (c->copygc_thread) 412 return 0; 413 414 if (c->opts.nochanges) 415 return 0; 416 417 if (bch2_fs_init_fault("copygc_start")) 418 return -ENOMEM; 419 420 t = kthread_create(bch2_copygc_thread, c, "bch-copygc/%s", c->name); 421 ret = PTR_ERR_OR_ZERO(t); 422 bch_err_msg(c, ret, "creating copygc thread"); 423 if (ret) 424 return ret; 425 426 get_task_struct(t); 427 428 c->copygc_thread = t; 429 wake_up_process(c->copygc_thread); 430 431 return 0; 432 } 433 434 void bch2_fs_copygc_init(struct bch_fs *c) 435 { 436 init_waitqueue_head(&c->copygc_running_wq); 437 c->copygc_running = false; 438 } 439