![Kent Overstreet](/assets/img/avatar_default.png)
Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
65 lines
1.5 KiB
C
65 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 >> d->stripe_size_bits;
|
|
|
|
while (1) {
|
|
if (atomic_read(d->stripe_sectors_dirty + stripe))
|
|
return true;
|
|
|
|
if (nr_sectors <= 1 << d->stripe_size_bits)
|
|
return false;
|
|
|
|
nr_sectors -= 1 << d->stripe_size_bits;
|
|
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
|