writeback.h
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#ifndef _BCACHE_WRITEBACK_H
#define _BCACHE_WRITEBACK_H
#define CUTOFF_WRITEBACK 40
#define CUTOFF_WRITEBACK_SYNC 70
static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
{
uint64_t i, ret = 0;
for (i = 0; i < d->nr_stripes; i++)
ret += atomic_read(d->stripe_sectors_dirty + i);
return ret;
}
static inline unsigned offset_to_stripe(struct bcache_device *d,
uint64_t offset)
{
do_div(offset, d->stripe_size);
return offset;
}
static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
uint64_t offset,
unsigned nr_sectors)
{
unsigned stripe = offset_to_stripe(&dc->disk, offset);
while (1) {
if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
return true;
if (nr_sectors <= dc->disk.stripe_size)
return false;
nr_sectors -= dc->disk.stripe_size;
stripe++;
}
}
static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
unsigned cache_mode, bool would_skip)
{
unsigned in_use = dc->disk.c->gc_stats.in_use;
if (cache_mode != CACHE_MODE_WRITEBACK ||
test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
in_use > CUTOFF_WRITEBACK_SYNC)
return false;
if (dc->partial_stripes_expensive &&
bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
bio_sectors(bio)))
return true;
if (would_skip)
return false;
return bio->bi_rw & REQ_SYNC ||
in_use <= CUTOFF_WRITEBACK;
}
static inline void bch_writeback_queue(struct cached_dev *dc)
{
wake_up_process(dc->writeback_thread);
}
static inline void bch_writeback_add(struct cached_dev *dc)
{
if (!atomic_read(&dc->has_dirty) &&
!atomic_xchg(&dc->has_dirty, 1)) {
atomic_inc(&dc->count);
if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
/* XXX: should do this synchronously */
bch_write_bdev_super(dc, NULL);
}
bch_writeback_queue(dc);
}
}
void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
void bch_sectors_dirty_init(struct cached_dev *dc);
int bch_cached_dev_writeback_init(struct cached_dev *);
#endif