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 /* 12 * 14 (16384ths) is chosen here as something that each backing device 13 * should be a reasonable fraction of the share, and not to blow up 14 * until individual backing devices are a petabyte. 15 */ 16 #define WRITEBACK_SHARE_SHIFT 14 17 18 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d) 19 { 20 uint64_t i, ret = 0; 21 22 for (i = 0; i < d->nr_stripes; i++) 23 ret += atomic_read(d->stripe_sectors_dirty + i); 24 25 return ret; 26 } 27 28 static inline uint64_t bcache_flash_devs_sectors_dirty(struct cache_set *c) 29 { 30 uint64_t i, ret = 0; 31 32 mutex_lock(&bch_register_lock); 33 34 for (i = 0; i < c->devices_max_used; i++) { 35 struct bcache_device *d = c->devices[i]; 36 37 if (!d || !UUID_FLASH_ONLY(&c->uuids[i])) 38 continue; 39 ret += bcache_dev_sectors_dirty(d); 40 } 41 42 mutex_unlock(&bch_register_lock); 43 44 return ret; 45 } 46 47 static inline unsigned offset_to_stripe(struct bcache_device *d, 48 uint64_t offset) 49 { 50 do_div(offset, d->stripe_size); 51 return offset; 52 } 53 54 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc, 55 uint64_t offset, 56 unsigned nr_sectors) 57 { 58 unsigned stripe = offset_to_stripe(&dc->disk, offset); 59 60 while (1) { 61 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe)) 62 return true; 63 64 if (nr_sectors <= dc->disk.stripe_size) 65 return false; 66 67 nr_sectors -= dc->disk.stripe_size; 68 stripe++; 69 } 70 } 71 72 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio, 73 unsigned cache_mode, bool would_skip) 74 { 75 unsigned in_use = dc->disk.c->gc_stats.in_use; 76 77 if (cache_mode != CACHE_MODE_WRITEBACK || 78 test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || 79 in_use > CUTOFF_WRITEBACK_SYNC) 80 return false; 81 82 if (dc->partial_stripes_expensive && 83 bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector, 84 bio_sectors(bio))) 85 return true; 86 87 if (would_skip) 88 return false; 89 90 return (op_is_sync(bio->bi_opf) || 91 bio->bi_opf & (REQ_META|REQ_PRIO) || 92 in_use <= CUTOFF_WRITEBACK); 93 } 94 95 static inline void bch_writeback_queue(struct cached_dev *dc) 96 { 97 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 98 wake_up_process(dc->writeback_thread); 99 } 100 101 static inline void bch_writeback_add(struct cached_dev *dc) 102 { 103 if (!atomic_read(&dc->has_dirty) && 104 !atomic_xchg(&dc->has_dirty, 1)) { 105 refcount_inc(&dc->count); 106 107 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) { 108 SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY); 109 /* XXX: should do this synchronously */ 110 bch_write_bdev_super(dc, NULL); 111 } 112 113 bch_writeback_queue(dc); 114 } 115 } 116 117 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int); 118 119 void bch_sectors_dirty_init(struct bcache_device *); 120 void bch_cached_dev_writeback_init(struct cached_dev *); 121 int bch_cached_dev_writeback_start(struct cached_dev *); 122 123 #endif 124