1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _BCACHE_WRITEBACK_H 3 #define _BCACHE_WRITEBACK_H 4 5 #define CUTOFF_WRITEBACK 40 6 #define CUTOFF_WRITEBACK_SYNC 70 7 8 #define MAX_WRITEBACKS_IN_PASS 5 9 #define MAX_WRITESIZE_IN_PASS 5000 /* *512b */ 10 11 #define WRITEBACK_RATE_UPDATE_SECS_MAX 60 12 #define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5 13 14 /* 15 * 14 (16384ths) is chosen here as something that each backing device 16 * should be a reasonable fraction of the share, and not to blow up 17 * until individual backing devices are a petabyte. 18 */ 19 #define WRITEBACK_SHARE_SHIFT 14 20 21 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d) 22 { 23 uint64_t i, ret = 0; 24 25 for (i = 0; i < d->nr_stripes; i++) 26 ret += atomic_read(d->stripe_sectors_dirty + i); 27 28 return ret; 29 } 30 31 static inline unsigned int offset_to_stripe(struct bcache_device *d, 32 uint64_t offset) 33 { 34 do_div(offset, d->stripe_size); 35 return offset; 36 } 37 38 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc, 39 uint64_t offset, 40 unsigned int nr_sectors) 41 { 42 unsigned int stripe = offset_to_stripe(&dc->disk, offset); 43 44 while (1) { 45 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe)) 46 return true; 47 48 if (nr_sectors <= dc->disk.stripe_size) 49 return false; 50 51 nr_sectors -= dc->disk.stripe_size; 52 stripe++; 53 } 54 } 55 56 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio, 57 unsigned int cache_mode, bool would_skip) 58 { 59 unsigned int in_use = dc->disk.c->gc_stats.in_use; 60 61 if (cache_mode != CACHE_MODE_WRITEBACK || 62 test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || 63 in_use > CUTOFF_WRITEBACK_SYNC) 64 return false; 65 66 if (dc->partial_stripes_expensive && 67 bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector, 68 bio_sectors(bio))) 69 return true; 70 71 if (would_skip) 72 return false; 73 74 return (op_is_sync(bio->bi_opf) || 75 bio->bi_opf & (REQ_META|REQ_PRIO) || 76 in_use <= CUTOFF_WRITEBACK); 77 } 78 79 static inline void bch_writeback_queue(struct cached_dev *dc) 80 { 81 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 82 wake_up_process(dc->writeback_thread); 83 } 84 85 static inline void bch_writeback_add(struct cached_dev *dc) 86 { 87 if (!atomic_read(&dc->has_dirty) && 88 !atomic_xchg(&dc->has_dirty, 1)) { 89 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) { 90 SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY); 91 /* XXX: should do this synchronously */ 92 bch_write_bdev_super(dc, NULL); 93 } 94 95 bch_writeback_queue(dc); 96 } 97 } 98 99 void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode, 100 uint64_t offset, int nr_sectors); 101 102 void bch_sectors_dirty_init(struct bcache_device *d); 103 void bch_cached_dev_writeback_init(struct cached_dev *dc); 104 int bch_cached_dev_writeback_start(struct cached_dev *dc); 105 106 #endif 107