1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Moving/copying garbage collector 4 * 5 * Copyright 2012 Google, Inc. 6 */ 7 8 #include "bcache.h" 9 #include "btree.h" 10 #include "debug.h" 11 #include "request.h" 12 13 #include <trace/events/bcache.h> 14 15 struct moving_io { 16 struct closure cl; 17 struct keybuf_key *w; 18 struct data_insert_op op; 19 struct bbio bio; 20 }; 21 22 static bool moving_pred(struct keybuf *buf, struct bkey *k) 23 { 24 struct cache_set *c = container_of(buf, struct cache_set, 25 moving_gc_keys); 26 unsigned int i; 27 28 for (i = 0; i < KEY_PTRS(k); i++) 29 if (ptr_available(c, k, i) && 30 GC_MOVE(PTR_BUCKET(c, k, i))) 31 return true; 32 33 return false; 34 } 35 36 /* Moving GC - IO loop */ 37 38 static CLOSURE_CALLBACK(moving_io_destructor) 39 { 40 closure_type(io, struct moving_io, cl); 41 42 kfree(io); 43 } 44 45 static CLOSURE_CALLBACK(write_moving_finish) 46 { 47 closure_type(io, struct moving_io, cl); 48 struct bio *bio = &io->bio.bio; 49 50 bio_free_pages(bio); 51 52 if (io->op.replace_collision) 53 trace_bcache_gc_copy_collision(&io->w->key); 54 55 bch_keybuf_del(&io->op.c->moving_gc_keys, io->w); 56 57 up(&io->op.c->moving_in_flight); 58 59 closure_return_with_destructor(cl, moving_io_destructor); 60 } 61 62 static void read_moving_endio(struct bio *bio) 63 { 64 struct bbio *b = container_of(bio, struct bbio, bio); 65 struct moving_io *io = container_of(bio->bi_private, 66 struct moving_io, cl); 67 68 if (bio->bi_status) 69 io->op.status = bio->bi_status; 70 else if (!KEY_DIRTY(&b->key) && 71 ptr_stale(io->op.c, &b->key, 0)) { 72 io->op.status = BLK_STS_IOERR; 73 } 74 75 bch_bbio_endio(io->op.c, bio, bio->bi_status, "reading data to move"); 76 } 77 78 static void moving_init(struct moving_io *io) 79 { 80 struct bio *bio = &io->bio.bio; 81 82 bio_init(bio, NULL, bio->bi_inline_vecs, 83 DIV_ROUND_UP(KEY_SIZE(&io->w->key), PAGE_SECTORS), 0); 84 bio_get(bio); 85 bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); 86 87 bio->bi_iter.bi_size = KEY_SIZE(&io->w->key) << 9; 88 bio->bi_private = &io->cl; 89 bch_bio_map(bio, NULL); 90 } 91 92 static CLOSURE_CALLBACK(write_moving) 93 { 94 closure_type(io, struct moving_io, cl); 95 struct data_insert_op *op = &io->op; 96 97 if (!op->status) { 98 moving_init(io); 99 100 io->bio.bio.bi_iter.bi_sector = KEY_START(&io->w->key); 101 op->write_prio = 1; 102 op->bio = &io->bio.bio; 103 104 op->writeback = KEY_DIRTY(&io->w->key); 105 op->csum = KEY_CSUM(&io->w->key); 106 107 bkey_copy(&op->replace_key, &io->w->key); 108 op->replace = true; 109 110 closure_call(&op->cl, bch_data_insert, NULL, cl); 111 } 112 113 continue_at(cl, write_moving_finish, op->wq); 114 } 115 116 static CLOSURE_CALLBACK(read_moving_submit) 117 { 118 closure_type(io, struct moving_io, cl); 119 struct bio *bio = &io->bio.bio; 120 121 bch_submit_bbio(bio, io->op.c, &io->w->key, 0); 122 123 continue_at(cl, write_moving, io->op.wq); 124 } 125 126 static void read_moving(struct cache_set *c) 127 { 128 struct keybuf_key *w; 129 struct moving_io *io; 130 struct bio *bio; 131 struct closure cl; 132 133 closure_init_stack(&cl); 134 135 /* XXX: if we error, background writeback could stall indefinitely */ 136 137 while (!test_bit(CACHE_SET_STOPPING, &c->flags)) { 138 w = bch_keybuf_next_rescan(c, &c->moving_gc_keys, 139 &MAX_KEY, moving_pred); 140 if (!w) 141 break; 142 143 if (ptr_stale(c, &w->key, 0)) { 144 bch_keybuf_del(&c->moving_gc_keys, w); 145 continue; 146 } 147 148 io = kzalloc(struct_size(io, bio.bio.bi_inline_vecs, 149 DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS)), 150 GFP_KERNEL); 151 if (!io) 152 goto err; 153 154 w->private = io; 155 io->w = w; 156 io->op.inode = KEY_INODE(&w->key); 157 io->op.c = c; 158 io->op.wq = c->moving_gc_wq; 159 160 moving_init(io); 161 bio = &io->bio.bio; 162 163 bio->bi_opf = REQ_OP_READ; 164 bio->bi_end_io = read_moving_endio; 165 166 if (bch_bio_alloc_pages(bio, GFP_KERNEL)) 167 goto err; 168 169 trace_bcache_gc_copy(&w->key); 170 171 down(&c->moving_in_flight); 172 closure_call(&io->cl, read_moving_submit, NULL, &cl); 173 } 174 175 if (0) { 176 err: if (!IS_ERR_OR_NULL(w->private)) 177 kfree(w->private); 178 179 bch_keybuf_del(&c->moving_gc_keys, w); 180 } 181 182 closure_sync(&cl); 183 } 184 185 static bool new_bucket_cmp(const void *l, const void *r, void __always_unused *args) 186 { 187 struct bucket **_l = (struct bucket **)l; 188 struct bucket **_r = (struct bucket **)r; 189 190 return GC_SECTORS_USED(*_l) >= GC_SECTORS_USED(*_r); 191 } 192 193 static void new_bucket_swap(void *l, void *r, void __always_unused *args) 194 { 195 struct bucket **_l = l; 196 struct bucket **_r = r; 197 198 swap(*_l, *_r); 199 } 200 201 static unsigned int bucket_heap_top(struct cache *ca) 202 { 203 struct bucket *b; 204 205 return (b = min_heap_peek(&ca->heap)[0]) ? GC_SECTORS_USED(b) : 0; 206 } 207 208 void bch_moving_gc(struct cache_set *c) 209 { 210 struct cache *ca = c->cache; 211 struct bucket *b; 212 unsigned long sectors_to_move, reserve_sectors; 213 const struct min_heap_callbacks callbacks = { 214 .less = new_bucket_cmp, 215 .swp = new_bucket_swap, 216 }; 217 218 if (!c->copy_gc_enabled) 219 return; 220 221 mutex_lock(&c->bucket_lock); 222 223 sectors_to_move = 0; 224 reserve_sectors = ca->sb.bucket_size * 225 fifo_used(&ca->free[RESERVE_MOVINGGC]); 226 227 ca->heap.nr = 0; 228 229 for_each_bucket(b, ca) { 230 if (GC_MARK(b) == GC_MARK_METADATA || 231 !GC_SECTORS_USED(b) || 232 GC_SECTORS_USED(b) == ca->sb.bucket_size || 233 atomic_read(&b->pin)) 234 continue; 235 236 if (!min_heap_full(&ca->heap)) { 237 sectors_to_move += GC_SECTORS_USED(b); 238 min_heap_push(&ca->heap, &b, &callbacks, NULL); 239 } else if (!new_bucket_cmp(&b, min_heap_peek(&ca->heap), ca)) { 240 sectors_to_move -= bucket_heap_top(ca); 241 sectors_to_move += GC_SECTORS_USED(b); 242 243 ca->heap.data[0] = b; 244 min_heap_sift_down(&ca->heap, 0, &callbacks, NULL); 245 } 246 } 247 248 while (sectors_to_move > reserve_sectors) { 249 if (ca->heap.nr) { 250 b = min_heap_peek(&ca->heap)[0]; 251 min_heap_pop(&ca->heap, &callbacks, NULL); 252 } 253 sectors_to_move -= GC_SECTORS_USED(b); 254 } 255 256 while (ca->heap.nr) { 257 b = min_heap_peek(&ca->heap)[0]; 258 min_heap_pop(&ca->heap, &callbacks, NULL); 259 SET_GC_MOVE(b, 1); 260 } 261 262 mutex_unlock(&c->bucket_lock); 263 264 c->moving_gc_keys.last_scanned = ZERO_KEY; 265 266 read_moving(c); 267 } 268 269 void bch_moving_init_cache_set(struct cache_set *c) 270 { 271 bch_keybuf_init(&c->moving_gc_keys); 272 sema_init(&c->moving_in_flight, 64); 273 } 274