linux/drivers/md/bcache/writeback.h
Kent Overstreet 2d679fc756 bcache: Stripe size isn't necessarily a power of two
Originally I got this right... except that the divides didn't use
do_div(), which broke 32 bit kernels. When I went to fix that, I forgot
that the raid stripe size usually isn't a power of two... doh

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-11-10 21:55:55 -08:00

67 lines
1.5 KiB
C

#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 bool bcache_dev_stripe_dirty(struct bcache_device *d,
uint64_t offset,
unsigned nr_sectors)
{
uint64_t stripe = offset;
do_div(stripe, d->stripe_size);
while (1) {
if (atomic_read(d->stripe_sectors_dirty + stripe))
return true;
if (nr_sectors <= d->stripe_size)
return false;
nr_sectors -= d->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 ||
atomic_read(&dc->disk.detaching) ||
in_use > CUTOFF_WRITEBACK_SYNC)
return false;
if (dc->partial_stripes_expensive &&
bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
bio_sectors(bio)))
return true;
if (would_skip)
return false;
return bio->bi_rw & REQ_SYNC ||
in_use <= CUTOFF_WRITEBACK;
}
void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
void bch_writeback_queue(struct cached_dev *);
void bch_writeback_add(struct cached_dev *);
void bch_sectors_dirty_init(struct cached_dev *dc);
void bch_cached_dev_writeback_init(struct cached_dev *);
#endif