175206cf9a
bcache uses a Proportion-Differentiation Controller algorithm to control writeback rate to cached devices. In the PD controller algorithm, dirty stripes of thin flash device should not be counted in, because flash only volumes never write back dirty data. Currently dirty stripe counter for thin flash device is not initialized when the thin flash device starts. Which means the following calculation in PD controller will reference an undefined dirty stripes number, and all cached devices attached to the same cache set where the thin flash device lies on may have an inaccurate writeback rate. This patch calles bch_sectors_dirty_init() in flash_dev_run(), to correctly initialize dirty stripe counter when the thin flash device starts to run. This patch also does following parameter data type change, -void bch_sectors_dirty_init(struct cached_dev *dc); +void bch_sectors_dirty_init(struct bcache_device *); to call this function conveniently in flash_dev_run(). (Commit log is composed by Coly Li) Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn> Reviewed-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
111 lines
2.5 KiB
C
111 lines
2.5 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 uint64_t bcache_flash_devs_sectors_dirty(struct cache_set *c)
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{
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uint64_t i, ret = 0;
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mutex_lock(&bch_register_lock);
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for (i = 0; i < c->nr_uuids; i++) {
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struct bcache_device *d = c->devices[i];
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if (!d || !UUID_FLASH_ONLY(&c->uuids[i]))
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continue;
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ret += bcache_dev_sectors_dirty(d);
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}
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mutex_unlock(&bch_register_lock);
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return ret;
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}
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static inline unsigned offset_to_stripe(struct bcache_device *d,
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uint64_t offset)
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{
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do_div(offset, d->stripe_size);
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return offset;
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}
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static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
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uint64_t offset,
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unsigned nr_sectors)
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{
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unsigned stripe = offset_to_stripe(&dc->disk, offset);
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while (1) {
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if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
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return true;
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if (nr_sectors <= dc->disk.stripe_size)
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return false;
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nr_sectors -= dc->disk.stripe_size;
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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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test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
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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, bio->bi_iter.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 op_is_sync(bio->bi_opf) || in_use <= CUTOFF_WRITEBACK;
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}
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static inline void bch_writeback_queue(struct cached_dev *dc)
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{
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if (!IS_ERR_OR_NULL(dc->writeback_thread))
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wake_up_process(dc->writeback_thread);
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}
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static inline void bch_writeback_add(struct cached_dev *dc)
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{
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if (!atomic_read(&dc->has_dirty) &&
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!atomic_xchg(&dc->has_dirty, 1)) {
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atomic_inc(&dc->count);
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if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
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SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
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/* XXX: should do this synchronously */
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bch_write_bdev_super(dc, NULL);
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}
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bch_writeback_queue(dc);
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}
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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_sectors_dirty_init(struct bcache_device *);
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void bch_cached_dev_writeback_init(struct cached_dev *);
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int bch_cached_dev_writeback_start(struct cached_dev *);
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#endif
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