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