drivers/md/bcache/writeback.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHE_WRITEBACK_H
   3 #define _BCACHE_WRITEBACK_H
   4
   5 #define CUTOFF_WRITEBACK        40
   6 #define CUTOFF_WRITEBACK_SYNC   70
   7
   8 #define MAX_WRITEBACKS_IN_PASS  5
   9 #define MAX_WRITESIZE_IN_PASS   5000    /* *512b */
  10
  11 /*
  12  * 14 (16384ths) is chosen here as something that each backing device
  13  * should be a reasonable fraction of the share, and not to blow up
  14  * until individual backing devices are a petabyte.
  15  */
  16 #define WRITEBACK_SHARE_SHIFT   14
  17
  18 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
  19 {
  20         uint64_t i, ret = 0;
  21
  22         for (i = 0; i < d->nr_stripes; i++)
  23                 ret += atomic_read(d->stripe_sectors_dirty + i);
  24
  25         return ret;
  26 }
  27
  28 static inline uint64_t  bcache_flash_devs_sectors_dirty(struct cache_set *c)
  29 {
  30         uint64_t i, ret = 0;
  31
  32         mutex_lock(&bch_register_lock);
  33
  34         for (i = 0; i < c->devices_max_used; i++) {
  35                 struct bcache_device *d = c->devices[i];
  36
  37                 if (!d || !UUID_FLASH_ONLY(&c->uuids[i]))
  38                         continue;
  39            ret += bcache_dev_sectors_dirty(d);
  40         }
  41
  42         mutex_unlock(&bch_register_lock);
  43
  44         return ret;
  45 }
  46
  47 static inline unsigned offset_to_stripe(struct bcache_device *d,
  48                                         uint64_t offset)
  49 {
  50         do_div(offset, d->stripe_size);
  51         return offset;
  52 }
  53
  54 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
  55                                            uint64_t offset,
  56                                            unsigned nr_sectors)
  57 {
  58         unsigned stripe = offset_to_stripe(&dc->disk, offset);
  59
  60         while (1) {
  61                 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
  62                         return true;
  63
  64                 if (nr_sectors <= dc->disk.stripe_size)
  65                         return false;
  66
  67                 nr_sectors -= dc->disk.stripe_size;
  68                 stripe++;
  69         }
  70 }
  71
  72 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
  73                                     unsigned cache_mode, bool would_skip)
  74 {
  75         unsigned in_use = dc->disk.c->gc_stats.in_use;
  76
  77         if (cache_mode != CACHE_MODE_WRITEBACK ||
  78             test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
  79             in_use > CUTOFF_WRITEBACK_SYNC)
  80                 return false;
  81
  82         if (dc->partial_stripes_expensive &&
  83             bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
  84                                     bio_sectors(bio)))
  85                 return true;
  86
  87         if (would_skip)
  88                 return false;
  89
  90         return (op_is_sync(bio->bi_opf) ||
  91                 bio->bi_opf & (REQ_META|REQ_PRIO) ||
  92                 in_use <= CUTOFF_WRITEBACK);
  93 }
  94
  95 static inline void bch_writeback_queue(struct cached_dev *dc)
  96 {
  97         if (!IS_ERR_OR_NULL(dc->writeback_thread))
  98                 wake_up_process(dc->writeback_thread);
  99 }
 100
 101 static inline void bch_writeback_add(struct cached_dev *dc)
 102 {
 103         if (!atomic_read(&dc->has_dirty) &&
 104             !atomic_xchg(&dc->has_dirty, 1)) {
 105                 refcount_inc(&dc->count);
 106
 107                 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
 108                         SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
 109                         /* XXX: should do this synchronously */
 110                         bch_write_bdev_super(dc, NULL);
 111                 }
 112
 113                 bch_writeback_queue(dc);
 114         }
 115 }
 116
 117 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
 118
 119 void bch_sectors_dirty_init(struct bcache_device *);
 120 void bch_cached_dev_writeback_init(struct cached_dev *);
 121 int bch_cached_dev_writeback_start(struct cached_dev *);
 122
 123 #endif