kernel/drivers/md/bcache/writeback.h

   1 #ifndef _BCACHE_WRITEBACK_H
   2 #define _BCACHE_WRITEBACK_H
   3
   4 #define CUTOFF_WRITEBACK        40
   5 #define CUTOFF_WRITEBACK_SYNC   70
   6
   7 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
   8 {
   9         uint64_t i, ret = 0;
  10
  11         for (i = 0; i < d->nr_stripes; i++)
  12                 ret += atomic_read(d->stripe_sectors_dirty + i);
  13
  14         return ret;
  15 }
  16
  17 static inline unsigned offset_to_stripe(struct bcache_device *d,
  18                                         uint64_t offset)
  19 {
  20         do_div(offset, d->stripe_size);
  21         return offset;
  22 }
  23
  24 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
  25                                            uint64_t offset,
  26                                            unsigned nr_sectors)
  27 {
  28         unsigned stripe = offset_to_stripe(&dc->disk, offset);
  29
  30         while (1) {
  31                 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
  32                         return true;
  33
  34                 if (nr_sectors <= dc->disk.stripe_size)
  35                         return false;
  36
  37                 nr_sectors -= dc->disk.stripe_size;
  38                 stripe++;
  39         }
  40 }
  41
  42 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
  43                                     unsigned cache_mode, bool would_skip)
  44 {
  45         unsigned in_use = dc->disk.c->gc_stats.in_use;
  46
  47         if (cache_mode != CACHE_MODE_WRITEBACK ||
  48             test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
  49             in_use > CUTOFF_WRITEBACK_SYNC)
  50                 return false;
  51
  52         if (dc->partial_stripes_expensive &&
  53             bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
  54                                     bio_sectors(bio)))
  55                 return true;
  56
  57         if (would_skip)
  58                 return false;
  59
  60         return bio->bi_rw & REQ_SYNC ||
  61                 in_use <= CUTOFF_WRITEBACK;
  62 }
  63
  64 static inline void bch_writeback_queue(struct cached_dev *dc)
  65 {
  66         wake_up_process(dc->writeback_thread);
  67 }
  68
  69 static inline void bch_writeback_add(struct cached_dev *dc)
  70 {
  71         if (!atomic_read(&dc->has_dirty) &&
  72             !atomic_xchg(&dc->has_dirty, 1)) {
  73                 atomic_inc(&dc->count);
  74
  75                 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
  76                         SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
  77                         /* XXX: should do this synchronously */
  78                         bch_write_bdev_super(dc, NULL);
  79                 }
  80
  81                 bch_writeback_queue(dc);
  82         }
  83 }
  84
  85 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
  86
  87 void bch_sectors_dirty_init(struct cached_dev *dc);
  88 void bch_cached_dev_writeback_init(struct cached_dev *);
  89 int bch_cached_dev_writeback_start(struct cached_dev *);
  90
  91 #endif