72c270612b
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>
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
#ifndef _BCACHE_WRITEBACK_H
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#define _BCACHE_WRITEBACK_H
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#define CUTOFF_WRITEBACK 40
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#define CUTOFF_WRITEBACK_SYNC 70
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static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
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{
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uint64_t i, ret = 0;
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for (i = 0; i < d->nr_stripes; i++)
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ret += atomic_read(d->stripe_sectors_dirty + i);
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return ret;
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}
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static inline bool bcache_dev_stripe_dirty(struct bcache_device *d,
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uint64_t offset,
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unsigned nr_sectors)
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{
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uint64_t stripe = offset >> d->stripe_size_bits;
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while (1) {
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if (atomic_read(d->stripe_sectors_dirty + stripe))
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return true;
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if (nr_sectors <= 1 << d->stripe_size_bits)
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return false;
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nr_sectors -= 1 << d->stripe_size_bits;
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stripe++;
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}
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}
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static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
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unsigned cache_mode, bool would_skip)
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{
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unsigned in_use = dc->disk.c->gc_stats.in_use;
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if (cache_mode != CACHE_MODE_WRITEBACK ||
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atomic_read(&dc->disk.detaching) ||
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in_use > CUTOFF_WRITEBACK_SYNC)
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return false;
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if (dc->partial_stripes_expensive &&
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bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
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bio_sectors(bio)))
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return true;
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if (would_skip)
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return false;
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return bio->bi_rw & REQ_SYNC ||
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in_use <= CUTOFF_WRITEBACK;
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}
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void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
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void bch_writeback_queue(struct cached_dev *);
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void bch_writeback_add(struct cached_dev *);
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void bch_sectors_dirty_init(struct cached_dev *dc);
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void bch_cached_dev_writeback_init(struct cached_dev *);
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#endif
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