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 bool bcache_dev_stripe_dirty(struct bcache_device *d,
  18                                            uint64_t offset,
  19                                            unsigned nr_sectors)
  20 {
  21         uint64_t stripe = offset >> d->stripe_size_bits;
  22
  23         while (1) {
  24                 if (atomic_read(d->stripe_sectors_dirty + stripe))
  25                         return true;
  26
  27                 if (nr_sectors <= 1 << d->stripe_size_bits)
  28                         return false;
  29
  30                 nr_sectors -= 1 << d->stripe_size_bits;
  31                 stripe++;
  32         }
  33 }
  34
  35 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
  36                                     unsigned cache_mode, bool would_skip)
  37 {
  38         unsigned in_use = dc->disk.c->gc_stats.in_use;
  39
  40         if (cache_mode != CACHE_MODE_WRITEBACK ||
  41             atomic_read(&dc->disk.detaching) ||
  42             in_use > CUTOFF_WRITEBACK_SYNC)
  43                 return false;
  44
  45         if (dc->partial_stripes_expensive &&
  46             bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
  47                                     bio_sectors(bio)))
  48                 return true;
  49
  50         if (would_skip)
  51                 return false;
  52
  53         return bio->bi_rw & REQ_SYNC ||
  54                 in_use <= CUTOFF_WRITEBACK;
  55 }
  56
  57 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
  58 void bch_writeback_queue(struct cached_dev *);
  59 void bch_writeback_add(struct cached_dev *);
  60
  61 void bch_sectors_dirty_init(struct cached_dev *dc);
  62 void bch_cached_dev_writeback_init(struct cached_dev *);
  63
  64 #endif