drivers/md/bcache/movinggc.c

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