| /* |
| * Moving/copying garbage collector |
| * |
| * Copyright 2012 Google, Inc. |
| */ |
| |
| #include "bcache.h" |
| #include "btree.h" |
| #include "debug.h" |
| #include "request.h" |
| |
| struct moving_io { |
| struct keybuf_key *w; |
| struct search s; |
| struct bbio bio; |
| }; |
| |
| static bool moving_pred(struct keybuf *buf, struct bkey *k) |
| { |
| struct cache_set *c = container_of(buf, struct cache_set, |
| moving_gc_keys); |
| unsigned i; |
| |
| for (i = 0; i < KEY_PTRS(k); i++) { |
| struct cache *ca = PTR_CACHE(c, k, i); |
| struct bucket *g = PTR_BUCKET(c, k, i); |
| |
| if (GC_SECTORS_USED(g) < ca->gc_move_threshold) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Moving GC - IO loop */ |
| |
| static void moving_io_destructor(struct closure *cl) |
| { |
| struct moving_io *io = container_of(cl, struct moving_io, s.cl); |
| kfree(io); |
| } |
| |
| static void write_moving_finish(struct closure *cl) |
| { |
| struct moving_io *io = container_of(cl, struct moving_io, s.cl); |
| struct bio *bio = &io->bio.bio; |
| struct bio_vec *bv = bio_iovec_idx(bio, bio->bi_vcnt); |
| |
| while (bv-- != bio->bi_io_vec) |
| __free_page(bv->bv_page); |
| |
| pr_debug("%s %s", io->s.op.insert_collision |
| ? "collision moving" : "moved", |
| pkey(&io->w->key)); |
| |
| bch_keybuf_del(&io->s.op.c->moving_gc_keys, io->w); |
| |
| atomic_dec_bug(&io->s.op.c->in_flight); |
| closure_wake_up(&io->s.op.c->moving_gc_wait); |
| |
| closure_return_with_destructor(cl, moving_io_destructor); |
| } |
| |
| static void read_moving_endio(struct bio *bio, int error) |
| { |
| struct moving_io *io = container_of(bio->bi_private, |
| struct moving_io, s.cl); |
| |
| if (error) |
| io->s.error = error; |
| |
| bch_bbio_endio(io->s.op.c, bio, error, "reading data to move"); |
| } |
| |
| static void moving_init(struct moving_io *io) |
| { |
| struct bio *bio = &io->bio.bio; |
| |
| bio_init(bio); |
| bio_get(bio); |
| bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); |
| |
| bio->bi_size = KEY_SIZE(&io->w->key) << 9; |
| bio->bi_max_vecs = DIV_ROUND_UP(KEY_SIZE(&io->w->key), |
| PAGE_SECTORS); |
| bio->bi_private = &io->s.cl; |
| bio->bi_io_vec = bio->bi_inline_vecs; |
| bio_map(bio, NULL); |
| } |
| |
| static void write_moving(struct closure *cl) |
| { |
| struct search *s = container_of(cl, struct search, cl); |
| struct moving_io *io = container_of(s, struct moving_io, s); |
| |
| if (!s->error) { |
| trace_bcache_write_moving(&io->bio.bio); |
| |
| moving_init(io); |
| |
| io->bio.bio.bi_sector = KEY_START(&io->w->key); |
| s->op.lock = -1; |
| s->op.write_prio = 1; |
| s->op.cache_bio = &io->bio.bio; |
| |
| s->writeback = KEY_DIRTY(&io->w->key); |
| s->op.csum = KEY_CSUM(&io->w->key); |
| |
| s->op.type = BTREE_REPLACE; |
| bkey_copy(&s->op.replace, &io->w->key); |
| |
| closure_init(&s->op.cl, cl); |
| bch_insert_data(&s->op.cl); |
| } |
| |
| continue_at(cl, write_moving_finish, NULL); |
| } |
| |
| static void read_moving_submit(struct closure *cl) |
| { |
| struct search *s = container_of(cl, struct search, cl); |
| struct moving_io *io = container_of(s, struct moving_io, s); |
| struct bio *bio = &io->bio.bio; |
| |
| trace_bcache_read_moving(bio); |
| bch_submit_bbio(bio, s->op.c, &io->w->key, 0); |
| |
| continue_at(cl, write_moving, bch_gc_wq); |
| } |
| |
| static void read_moving(struct closure *cl) |
| { |
| struct cache_set *c = container_of(cl, struct cache_set, moving_gc); |
| struct keybuf_key *w; |
| struct moving_io *io; |
| struct bio *bio; |
| |
| /* XXX: if we error, background writeback could stall indefinitely */ |
| |
| while (!test_bit(CACHE_SET_STOPPING, &c->flags)) { |
| w = bch_keybuf_next_rescan(c, &c->moving_gc_keys, &MAX_KEY); |
| if (!w) |
| break; |
| |
| io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec) |
| * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), |
| GFP_KERNEL); |
| if (!io) |
| goto err; |
| |
| w->private = io; |
| io->w = w; |
| io->s.op.inode = KEY_INODE(&w->key); |
| io->s.op.c = c; |
| |
| moving_init(io); |
| bio = &io->bio.bio; |
| |
| bio->bi_rw = READ; |
| bio->bi_end_io = read_moving_endio; |
| |
| if (bio_alloc_pages(bio, GFP_KERNEL)) |
| goto err; |
| |
| pr_debug("%s", pkey(&w->key)); |
| |
| closure_call(&io->s.cl, read_moving_submit, NULL, &c->gc.cl); |
| |
| if (atomic_inc_return(&c->in_flight) >= 64) { |
| closure_wait_event(&c->moving_gc_wait, cl, |
| atomic_read(&c->in_flight) < 64); |
| continue_at(cl, read_moving, bch_gc_wq); |
| } |
| } |
| |
| if (0) { |
| err: if (!IS_ERR_OR_NULL(w->private)) |
| kfree(w->private); |
| |
| bch_keybuf_del(&c->moving_gc_keys, w); |
| } |
| |
| closure_return(cl); |
| } |
| |
| static bool bucket_cmp(struct bucket *l, struct bucket *r) |
| { |
| return GC_SECTORS_USED(l) < GC_SECTORS_USED(r); |
| } |
| |
| static unsigned bucket_heap_top(struct cache *ca) |
| { |
| return GC_SECTORS_USED(heap_peek(&ca->heap)); |
| } |
| |
| void bch_moving_gc(struct closure *cl) |
| { |
| struct cache_set *c = container_of(cl, struct cache_set, gc.cl); |
| struct cache *ca; |
| struct bucket *b; |
| unsigned i; |
| |
| if (!c->copy_gc_enabled) |
| closure_return(cl); |
| |
| mutex_lock(&c->bucket_lock); |
| |
| for_each_cache(ca, c, i) { |
| unsigned sectors_to_move = 0; |
| unsigned reserve_sectors = ca->sb.bucket_size * |
| min(fifo_used(&ca->free), ca->free.size / 2); |
| |
| ca->heap.used = 0; |
| |
| for_each_bucket(b, ca) { |
| if (!GC_SECTORS_USED(b)) |
| continue; |
| |
| if (!heap_full(&ca->heap)) { |
| sectors_to_move += GC_SECTORS_USED(b); |
| heap_add(&ca->heap, b, bucket_cmp); |
| } else if (bucket_cmp(b, heap_peek(&ca->heap))) { |
| sectors_to_move -= bucket_heap_top(ca); |
| sectors_to_move += GC_SECTORS_USED(b); |
| |
| ca->heap.data[0] = b; |
| heap_sift(&ca->heap, 0, bucket_cmp); |
| } |
| } |
| |
| while (sectors_to_move > reserve_sectors) { |
| heap_pop(&ca->heap, b, bucket_cmp); |
| sectors_to_move -= GC_SECTORS_USED(b); |
| } |
| |
| ca->gc_move_threshold = bucket_heap_top(ca); |
| |
| pr_debug("threshold %u", ca->gc_move_threshold); |
| } |
| |
| mutex_unlock(&c->bucket_lock); |
| |
| c->moving_gc_keys.last_scanned = ZERO_KEY; |
| |
| closure_init(&c->moving_gc, cl); |
| read_moving(&c->moving_gc); |
| |
| closure_return(cl); |
| } |
| |
| void bch_moving_init_cache_set(struct cache_set *c) |
| { |
| bch_keybuf_init(&c->moving_gc_keys, moving_pred); |
| } |