Pileus Git - ~andy/linux/blob - 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;
  22
  23         do_div(stripe, d->stripe_size);
  24
  25         while (1) {
  26                 if (atomic_read(d->stripe_sectors_dirty + stripe))
  27                         return true;
  28
  29                 if (nr_sectors <= d->stripe_size)
  30                         return false;
  31
  32                 nr_sectors -= d->stripe_size;
  33                 stripe++;
  34         }
  35 }
  36
  37 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
  38                                     unsigned cache_mode, bool would_skip)
  39 {
  40         unsigned in_use = dc->disk.c->gc_stats.in_use;
  41
  42         if (cache_mode != CACHE_MODE_WRITEBACK ||
  43             atomic_read(&dc->disk.detaching) ||
  44             in_use > CUTOFF_WRITEBACK_SYNC)
  45                 return false;
  46
  47         if (dc->partial_stripes_expensive &&
  48             bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
  49                                     bio_sectors(bio)))
  50                 return true;
  51
  52         if (would_skip)
  53                 return false;
  54
  55         return bio->bi_rw & REQ_SYNC ||
  56                 in_use <= CUTOFF_WRITEBACK;
  57 }
  58
  59 static inline void bch_writeback_queue(struct cached_dev *dc)
  60 {
  61         wake_up_process(dc->writeback_thread);
  62 }
  63
  64 static inline void bch_writeback_add(struct cached_dev *dc)
  65 {
  66         if (!atomic_read(&dc->has_dirty) &&
  67             !atomic_xchg(&dc->has_dirty, 1)) {
  68                 atomic_inc(&dc->count);
  69
  70                 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
  71                         SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
  72                         /* XXX: should do this synchronously */
  73                         bch_write_bdev_super(dc, NULL);
  74                 }
  75
  76                 bch_writeback_queue(dc);
  77         }
  78 }
  79
  80 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
  81
  82 void bch_sectors_dirty_init(struct cached_dev *dc);
  83 int bch_cached_dev_writeback_init(struct cached_dev *);
  84
  85 #endif