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
15struct moving_io {
16	struct closure		cl;
17	struct keybuf_key	*w;
18	struct data_insert_op	op;
19	struct bbio		bio;
20};
21
22static 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
38static CLOSURE_CALLBACK(moving_io_destructor)
39{
40	closure_type(io, struct moving_io, cl);
41
42	kfree(io);
43}
44
45static 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
62static 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
78static 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
92static 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
116static 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
126static 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) {
176err:		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
185static bool bucket_cmp(struct bucket *l, struct bucket *r)
186{
187	return GC_SECTORS_USED(l) < GC_SECTORS_USED(r);
188}
189
190static unsigned int bucket_heap_top(struct cache *ca)
191{
192	struct bucket *b;
193
194	return (b = heap_peek(&ca->heap)) ? GC_SECTORS_USED(b) : 0;
195}
196
197void bch_moving_gc(struct cache_set *c)
198{
199	struct cache *ca = c->cache;
200	struct bucket *b;
201	unsigned long sectors_to_move, reserve_sectors;
202
203	if (!c->copy_gc_enabled)
204		return;
205
206	mutex_lock(&c->bucket_lock);
207
208	sectors_to_move = 0;
209	reserve_sectors = ca->sb.bucket_size *
210			     fifo_used(&ca->free[RESERVE_MOVINGGC]);
211
212	ca->heap.used = 0;
213
214	for_each_bucket(b, ca) {
215		if (GC_MARK(b) == GC_MARK_METADATA ||
216		    !GC_SECTORS_USED(b) ||
217		    GC_SECTORS_USED(b) == ca->sb.bucket_size ||
218		    atomic_read(&b->pin))
219			continue;
220
221		if (!heap_full(&ca->heap)) {
222			sectors_to_move += GC_SECTORS_USED(b);
223			heap_add(&ca->heap, b, bucket_cmp);
224		} else if (bucket_cmp(b, heap_peek(&ca->heap))) {
225			sectors_to_move -= bucket_heap_top(ca);
226			sectors_to_move += GC_SECTORS_USED(b);
227
228			ca->heap.data[0] = b;
229			heap_sift(&ca->heap, 0, bucket_cmp);
230		}
231	}
232
233	while (sectors_to_move > reserve_sectors) {
234		heap_pop(&ca->heap, b, bucket_cmp);
235		sectors_to_move -= GC_SECTORS_USED(b);
236	}
237
238	while (heap_pop(&ca->heap, b, bucket_cmp))
239		SET_GC_MOVE(b, 1);
240
241	mutex_unlock(&c->bucket_lock);
242
243	c->moving_gc_keys.last_scanned = ZERO_KEY;
244
245	read_moving(c);
246}
247
248void bch_moving_init_cache_set(struct cache_set *c)
249{
250	bch_keybuf_init(&c->moving_gc_keys);
251	sema_init(&c->moving_in_flight, 64);
252}
253