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 uint64_t bcache_flash_devs_sectors_dirty(struct cache_set *c) 32 { 33 uint64_t i, ret = 0; 34 35 mutex_lock(&bch_register_lock); 36 37 for (i = 0; i < c->devices_max_used; i++) { 38 struct bcache_device *d = c->devices[i]; 39 40 if (!d || !UUID_FLASH_ONLY(&c->uuids[i])) 41 continue; 42 ret += bcache_dev_sectors_dirty(d); 43 } 44 45 mutex_unlock(&bch_register_lock); 46 47 return ret; 48 } 49 50 static inline unsigned offset_to_stripe(struct bcache_device *d, 51 uint64_t offset) 52 { 53 do_div(offset, d->stripe_size); 54 return offset; 55 } 56 57 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc, 58 uint64_t offset, 59 unsigned nr_sectors) 60 { 61 unsigned stripe = offset_to_stripe(&dc->disk, offset); 62 63 while (1) { 64 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe)) 65 return true; 66 67 if (nr_sectors <= dc->disk.stripe_size) 68 return false; 69 70 nr_sectors -= dc->disk.stripe_size; 71 stripe++; 72 } 73 } 74 75 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio, 76 unsigned cache_mode, bool would_skip) 77 { 78 unsigned in_use = dc->disk.c->gc_stats.in_use; 79 80 if (cache_mode != CACHE_MODE_WRITEBACK || 81 test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || 82 in_use > CUTOFF_WRITEBACK_SYNC) 83 return false; 84 85 if (dc->partial_stripes_expensive && 86 bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector, 87 bio_sectors(bio))) 88 return true; 89 90 if (would_skip) 91 return false; 92 93 return (op_is_sync(bio->bi_opf) || 94 bio->bi_opf & (REQ_META|REQ_PRIO) || 95 in_use <= CUTOFF_WRITEBACK); 96 } 97 98 static inline void bch_writeback_queue(struct cached_dev *dc) 99 { 100 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 101 wake_up_process(dc->writeback_thread); 102 } 103 104 static inline void bch_writeback_add(struct cached_dev *dc) 105 { 106 if (!atomic_read(&dc->has_dirty) && 107 !atomic_xchg(&dc->has_dirty, 1)) { 108 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) { 109 SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY); 110 /* XXX: should do this synchronously */ 111 bch_write_bdev_super(dc, NULL); 112 } 113 114 bch_writeback_queue(dc); 115 } 116 } 117 118 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int); 119 120 void bch_sectors_dirty_init(struct bcache_device *); 121 void bch_cached_dev_writeback_init(struct cached_dev *); 122 int bch_cached_dev_writeback_start(struct cached_dev *); 123 124 #endif 125