summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/md/bcache/movinggc.c
blob: b929fc944e9c605a523766d20e711747a5f31fd0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
/*
 * Moving/copying garbage collector
 *
 * Copyright 2012 Google, Inc.
 */

#include "bcache.h"
#include "btree.h"
#include "debug.h"
#include "request.h"

#include <trace/events/bcache.h>

struct moving_io {
	struct closure		cl;
	struct keybuf_key	*w;
	struct data_insert_op	op;
	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++)
		if (ptr_available(c, k, i) &&
		    GC_MOVE(PTR_BUCKET(c, k, i)))
			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, cl);
	kfree(io);
}

static void write_moving_finish(struct closure *cl)
{
	struct moving_io *io = container_of(cl, struct moving_io, cl);
	struct bio *bio = &io->bio.bio;
	struct bio_vec *bv;
	int i;

	bio_for_each_segment_all(bv, bio, i)
		__free_page(bv->bv_page);

	if (io->op.replace_collision)
		trace_bcache_gc_copy_collision(&io->w->key);

	bch_keybuf_del(&io->op.c->moving_gc_keys, io->w);

	up(&io->op.c->moving_in_flight);

	closure_return_with_destructor(cl, moving_io_destructor);
}

static void read_moving_endio(struct bio *bio)
{
	struct bbio *b = container_of(bio, struct bbio, bio);
	struct moving_io *io = container_of(bio->bi_private,
					    struct moving_io, cl);

	if (bio->bi_error)
		io->op.error = bio->bi_error;
	else if (!KEY_DIRTY(&b->key) &&
		 ptr_stale(io->op.c, &b->key, 0)) {
		io->op.error = -EINTR;
	}

	bch_bbio_endio(io->op.c, bio, bio->bi_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_iter.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->cl;
	bio->bi_io_vec		= bio->bi_inline_vecs;
	bch_bio_map(bio, NULL);
}

static void write_moving(struct closure *cl)
{
	struct moving_io *io = container_of(cl, struct moving_io, cl);
	struct data_insert_op *op = &io->op;

	if (!op->error) {
		moving_init(io);

		io->bio.bio.bi_iter.bi_sector = KEY_START(&io->w->key);
		op->write_prio		= 1;
		op->bio			= &io->bio.bio;

		op->writeback		= KEY_DIRTY(&io->w->key);
		op->csum		= KEY_CSUM(&io->w->key);

		bkey_copy(&op->replace_key, &io->w->key);
		op->replace		= true;

		closure_call(&op->cl, bch_data_insert, NULL, cl);
	}

	continue_at(cl, write_moving_finish, op->wq);
}

static void read_moving_submit(struct closure *cl)
{
	struct moving_io *io = container_of(cl, struct moving_io, cl);
	struct bio *bio = &io->bio.bio;

	bch_submit_bbio(bio, io->op.c, &io->w->key, 0);

	continue_at(cl, write_moving, io->op.wq);
}

static void read_moving(struct cache_set *c)
{
	struct keybuf_key *w;
	struct moving_io *io;
	struct bio *bio;
	struct closure cl;

	closure_init_stack(&cl);

	/* 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, moving_pred);
		if (!w)
			break;

		if (ptr_stale(c, &w->key, 0)) {
			bch_keybuf_del(&c->moving_gc_keys, w);
			continue;
		}

		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->op.inode	= KEY_INODE(&w->key);
		io->op.c	= c;
		io->op.wq	= c->moving_gc_wq;

		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;

		trace_bcache_gc_copy(&w->key);

		down(&c->moving_in_flight);
		closure_call(&io->cl, read_moving_submit, NULL, &cl);
	}

	if (0) {
err:		if (!IS_ERR_OR_NULL(w->private))
			kfree(w->private);

		bch_keybuf_del(&c->moving_gc_keys, w);
	}

	closure_sync(&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)
{
	struct bucket *b;
	return (b = heap_peek(&ca->heap)) ? GC_SECTORS_USED(b) : 0;
}

void bch_moving_gc(struct cache_set *c)
{
	struct cache *ca;
	struct bucket *b;
	unsigned i;

	if (!c->copy_gc_enabled)
		return;

	mutex_lock(&c->bucket_lock);

	for_each_cache(ca, c, i) {
		unsigned sectors_to_move = 0;
		unsigned reserve_sectors = ca->sb.bucket_size *
			fifo_used(&ca->free[RESERVE_MOVINGGC]);

		ca->heap.used = 0;

		for_each_bucket(b, ca) {
			if (GC_MARK(b) == GC_MARK_METADATA ||
			    !GC_SECTORS_USED(b) ||
			    GC_SECTORS_USED(b) == ca->sb.bucket_size ||
			    atomic_read(&b->pin))
				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);
		}

		while (heap_pop(&ca->heap, b, bucket_cmp))
			SET_GC_MOVE(b, 1);
	}

	mutex_unlock(&c->bucket_lock);

	c->moving_gc_keys.last_scanned = ZERO_KEY;

	read_moving(c);
}

void bch_moving_init_cache_set(struct cache_set *c)
{
	bch_keybuf_init(&c->moving_gc_keys);
	sema_init(&c->moving_in_flight, 64);
}