/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _BCACHE_WRITEBACK_H #define _BCACHE_WRITEBACK_H #define CUTOFF_WRITEBACK 40 #define CUTOFF_WRITEBACK_SYNC 70 #define MAX_WRITEBACKS_IN_PASS 5 #define MAX_WRITESIZE_IN_PASS 5000 /* *512b */ #define WRITEBACK_RATE_UPDATE_SECS_MAX 60 #define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5 /* * 14 (16384ths) is chosen here as something that each backing device * should be a reasonable fraction of the share, and not to blow up * until individual backing devices are a petabyte. */ #define WRITEBACK_SHARE_SHIFT 14 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 int 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 int nr_sectors) { unsigned int 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 int cache_mode, bool would_skip) { unsigned int 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 (bio_op(bio) == REQ_OP_DISCARD) 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 (op_is_sync(bio->bi_opf) || bio->bi_opf & (REQ_META|REQ_PRIO) || in_use <= CUTOFF_WRITEBACK); } static inline void bch_writeback_queue(struct cached_dev *dc) { if (!IS_ERR_OR_NULL(dc->writeback_thread)) 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)) { 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 *c, unsigned int inode, uint64_t offset, int nr_sectors); void bch_sectors_dirty_init(struct bcache_device *d); void bch_cached_dev_writeback_init(struct cached_dev *dc); int bch_cached_dev_writeback_start(struct cached_dev *dc); #endif