// SPDX-License-Identifier: GPL-2.0 /* * Moving/copying garbage collector * * Copyright 2012 Google, Inc. */ #include "bcachefs.h" #include "alloc_background.h" #include "alloc_foreground.h" #include "btree_iter.h" #include "btree_update.h" #include "btree_write_buffer.h" #include "buckets.h" #include "clock.h" #include "errcode.h" #include "error.h" #include "lru.h" #include "move.h" #include "movinggc.h" #include "trace.h" #include #include #include #include #include struct buckets_in_flight { struct rhashtable table; struct move_bucket_in_flight *first; struct move_bucket_in_flight *last; size_t nr; size_t sectors; }; static const struct rhashtable_params bch_move_bucket_params = { .head_offset = offsetof(struct move_bucket_in_flight, hash), .key_offset = offsetof(struct move_bucket_in_flight, bucket.k), .key_len = sizeof(struct move_bucket_key), }; static struct move_bucket_in_flight * move_bucket_in_flight_add(struct buckets_in_flight *list, struct move_bucket b) { struct move_bucket_in_flight *new = kzalloc(sizeof(*new), GFP_KERNEL); int ret; if (!new) return ERR_PTR(-ENOMEM); new->bucket = b; ret = rhashtable_lookup_insert_fast(&list->table, &new->hash, bch_move_bucket_params); if (ret) { kfree(new); return ERR_PTR(ret); } if (!list->first) list->first = new; else list->last->next = new; list->last = new; list->nr++; list->sectors += b.sectors; return new; } static int bch2_bucket_is_movable(struct btree_trans *trans, struct move_bucket *b, u64 time) { struct btree_iter iter; struct bkey_s_c k; struct bch_alloc_v4 _a; const struct bch_alloc_v4 *a; int ret; if (bch2_bucket_is_open(trans->c, b->k.bucket.inode, b->k.bucket.offset)) return 0; k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc, b->k.bucket, BTREE_ITER_cached); ret = bkey_err(k); if (ret) return ret; a = bch2_alloc_to_v4(k, &_a); b->k.gen = a->gen; b->sectors = bch2_bucket_sectors_dirty(*a); ret = data_type_movable(a->data_type) && a->fragmentation_lru && a->fragmentation_lru <= time; bch2_trans_iter_exit(trans, &iter); return ret; } static void move_buckets_wait(struct moving_context *ctxt, struct buckets_in_flight *list, bool flush) { struct move_bucket_in_flight *i; int ret; while ((i = list->first)) { if (flush) move_ctxt_wait_event(ctxt, !atomic_read(&i->count)); if (atomic_read(&i->count)) break; list->first = i->next; if (!list->first) list->last = NULL; list->nr--; list->sectors -= i->bucket.sectors; ret = rhashtable_remove_fast(&list->table, &i->hash, bch_move_bucket_params); BUG_ON(ret); kfree(i); } bch2_trans_unlock_long(ctxt->trans); } static bool bucket_in_flight(struct buckets_in_flight *list, struct move_bucket_key k) { return rhashtable_lookup_fast(&list->table, &k, bch_move_bucket_params); } typedef DARRAY(struct move_bucket) move_buckets; static int bch2_copygc_get_buckets(struct moving_context *ctxt, struct buckets_in_flight *buckets_in_flight, move_buckets *buckets) { struct btree_trans *trans = ctxt->trans; struct bch_fs *c = trans->c; size_t nr_to_get = max_t(size_t, 16U, buckets_in_flight->nr / 4); size_t saw = 0, in_flight = 0, not_movable = 0, sectors = 0; int ret; move_buckets_wait(ctxt, buckets_in_flight, false); ret = bch2_btree_write_buffer_tryflush(trans); if (bch2_err_matches(ret, EROFS)) return ret; if (bch2_fs_fatal_err_on(ret, c, "%s: from bch2_btree_write_buffer_tryflush()", bch2_err_str(ret))) return ret; ret = for_each_btree_key_upto(trans, iter, BTREE_ID_lru, lru_pos(BCH_LRU_FRAGMENTATION_START, 0, 0), lru_pos(BCH_LRU_FRAGMENTATION_START, U64_MAX, LRU_TIME_MAX), 0, k, ({ struct move_bucket b = { .k.bucket = u64_to_bucket(k.k->p.offset) }; int ret2 = 0; saw++; ret2 = bch2_bucket_is_movable(trans, &b, lru_pos_time(k.k->p)); if (ret2 < 0) goto err; if (!ret2) not_movable++; else if (bucket_in_flight(buckets_in_flight, b.k)) in_flight++; else { ret2 = darray_push(buckets, b); if (ret2) goto err; sectors += b.sectors; } ret2 = buckets->nr >= nr_to_get; err: ret2; })); pr_debug("have: %zu (%zu) saw %zu in flight %zu not movable %zu got %zu (%zu)/%zu buckets ret %i", buckets_in_flight->nr, buckets_in_flight->sectors, saw, in_flight, not_movable, buckets->nr, sectors, nr_to_get, ret); return ret < 0 ? ret : 0; } noinline static int bch2_copygc(struct moving_context *ctxt, struct buckets_in_flight *buckets_in_flight, bool *did_work) { struct btree_trans *trans = ctxt->trans; struct bch_fs *c = trans->c; struct data_update_opts data_opts = { .btree_insert_flags = BCH_WATERMARK_copygc, }; move_buckets buckets = { 0 }; struct move_bucket_in_flight *f; u64 moved = atomic64_read(&ctxt->stats->sectors_moved); int ret = 0; ret = bch2_copygc_get_buckets(ctxt, buckets_in_flight, &buckets); if (ret) goto err; darray_for_each(buckets, i) { if (kthread_should_stop() || freezing(current)) break; f = move_bucket_in_flight_add(buckets_in_flight, *i); ret = PTR_ERR_OR_ZERO(f); if (ret == -EEXIST) { /* rare race: copygc_get_buckets returned same bucket more than once */ ret = 0; continue; } if (ret == -ENOMEM) { /* flush IO, continue later */ ret = 0; break; } ret = bch2_evacuate_bucket(ctxt, f, f->bucket.k.bucket, f->bucket.k.gen, data_opts); if (ret) goto err; *did_work = true; } err: darray_exit(&buckets); /* no entries in LRU btree found, or got to end: */ if (bch2_err_matches(ret, ENOENT)) ret = 0; if (ret < 0 && !bch2_err_matches(ret, EROFS)) bch_err_msg(c, ret, "from bch2_move_data()"); moved = atomic64_read(&ctxt->stats->sectors_moved) - moved; trace_and_count(c, copygc, c, moved, 0, 0, 0); return ret; } /* * Copygc runs when the amount of fragmented data is above some arbitrary * threshold: * * The threshold at the limit - when the device is full - is the amount of space * we reserved in bch2_recalc_capacity; we can't have more than that amount of * disk space stranded due to fragmentation and store everything we have * promised to store. * * But we don't want to be running copygc unnecessarily when the device still * has plenty of free space - rather, we want copygc to smoothly run every so * often and continually reduce the amount of fragmented space as the device * fills up. So, we increase the threshold by half the current free space. */ unsigned long bch2_copygc_wait_amount(struct bch_fs *c) { s64 wait = S64_MAX, fragmented_allowed, fragmented; for_each_rw_member(c, ca) { struct bch_dev_usage usage = bch2_dev_usage_read(ca); fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) * ca->mi.bucket_size) >> 1); fragmented = 0; for (unsigned i = 0; i < BCH_DATA_NR; i++) if (data_type_movable(i)) fragmented += usage.d[i].fragmented; wait = min(wait, max(0LL, fragmented_allowed - fragmented)); } return wait; } void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c) { prt_printf(out, "Currently waiting for: "); prt_human_readable_u64(out, max(0LL, c->copygc_wait - atomic64_read(&c->io_clock[WRITE].now)) << 9); prt_newline(out); prt_printf(out, "Currently waiting since: "); prt_human_readable_u64(out, max(0LL, atomic64_read(&c->io_clock[WRITE].now) - c->copygc_wait_at) << 9); prt_newline(out); prt_printf(out, "Currently calculated wait: "); prt_human_readable_u64(out, bch2_copygc_wait_amount(c)); prt_newline(out); } static int bch2_copygc_thread(void *arg) { struct bch_fs *c = arg; struct moving_context ctxt; struct bch_move_stats move_stats; struct io_clock *clock = &c->io_clock[WRITE]; struct buckets_in_flight *buckets; u64 last, wait; int ret = 0; buckets = kzalloc(sizeof(struct buckets_in_flight), GFP_KERNEL); if (!buckets) return -ENOMEM; ret = rhashtable_init(&buckets->table, &bch_move_bucket_params); bch_err_msg(c, ret, "allocating copygc buckets in flight"); if (ret) { kfree(buckets); return ret; } set_freezable(); bch2_move_stats_init(&move_stats, "copygc"); bch2_moving_ctxt_init(&ctxt, c, NULL, &move_stats, writepoint_ptr(&c->copygc_write_point), false); while (!ret && !kthread_should_stop()) { bool did_work = false; bch2_trans_unlock_long(ctxt.trans); cond_resched(); if (!c->copy_gc_enabled) { move_buckets_wait(&ctxt, buckets, true); kthread_wait_freezable(c->copy_gc_enabled || kthread_should_stop()); } if (unlikely(freezing(current))) { move_buckets_wait(&ctxt, buckets, true); __refrigerator(false); continue; } last = atomic64_read(&clock->now); wait = bch2_copygc_wait_amount(c); if (wait > clock->max_slop) { c->copygc_wait_at = last; c->copygc_wait = last + wait; move_buckets_wait(&ctxt, buckets, true); trace_and_count(c, copygc_wait, c, wait, last + wait); bch2_kthread_io_clock_wait(clock, last + wait, MAX_SCHEDULE_TIMEOUT); continue; } c->copygc_wait = 0; c->copygc_running = true; ret = bch2_copygc(&ctxt, buckets, &did_work); c->copygc_running = false; wake_up(&c->copygc_running_wq); if (!wait && !did_work) { u64 min_member_capacity = bch2_min_rw_member_capacity(c); if (min_member_capacity == U64_MAX) min_member_capacity = 128 * 2048; bch2_trans_unlock_long(ctxt.trans); bch2_kthread_io_clock_wait(clock, last + (min_member_capacity >> 6), MAX_SCHEDULE_TIMEOUT); } } move_buckets_wait(&ctxt, buckets, true); rhashtable_destroy(&buckets->table); kfree(buckets); bch2_moving_ctxt_exit(&ctxt); bch2_move_stats_exit(&move_stats, c); return 0; } void bch2_copygc_stop(struct bch_fs *c) { if (c->copygc_thread) { kthread_stop(c->copygc_thread); put_task_struct(c->copygc_thread); } c->copygc_thread = NULL; } int bch2_copygc_start(struct bch_fs *c) { struct task_struct *t; int ret; if (c->copygc_thread) return 0; if (c->opts.nochanges) return 0; if (bch2_fs_init_fault("copygc_start")) return -ENOMEM; t = kthread_create(bch2_copygc_thread, c, "bch-copygc/%s", c->name); ret = PTR_ERR_OR_ZERO(t); bch_err_msg(c, ret, "creating copygc thread"); if (ret) return ret; get_task_struct(t); c->copygc_thread = t; wake_up_process(c->copygc_thread); return 0; } void bch2_fs_copygc_init(struct bch_fs *c) { init_waitqueue_head(&c->copygc_running_wq); c->copygc_running = false; }