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 CUTOFF_WRITEBACK_MAX 70 9 #define CUTOFF_WRITEBACK_SYNC_MAX 90 10 11 #define MAX_WRITEBACKS_IN_PASS 5 12 #define MAX_WRITESIZE_IN_PASS 5000 /* *512b */ 13 14 #define WRITEBACK_RATE_UPDATE_SECS_MAX 60 15 #define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5 16 17 #define BCH_AUTO_GC_DIRTY_THRESHOLD 50 18 19 /* 20 * 14 (16384ths) is chosen here as something that each backing device 21 * should be a reasonable fraction of the share, and not to blow up 22 * until individual backing devices are a petabyte. 23 */ 24 #define WRITEBACK_SHARE_SHIFT 14 25 26 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d) 27 { 28 uint64_t i, ret = 0; 29 30 for (i = 0; i < d->nr_stripes; i++) 31 ret += atomic_read(d->stripe_sectors_dirty + i); 32 33 return ret; 34 } 35 36 static inline unsigned int offset_to_stripe(struct bcache_device *d, 37 uint64_t offset) 38 { 39 do_div(offset, d->stripe_size); 40 return offset; 41 } 42 43 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc, 44 uint64_t offset, 45 unsigned int nr_sectors) 46 { 47 unsigned int stripe = offset_to_stripe(&dc->disk, offset); 48 49 while (1) { 50 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe)) 51 return true; 52 53 if (nr_sectors <= dc->disk.stripe_size) 54 return false; 55 56 nr_sectors -= dc->disk.stripe_size; 57 stripe++; 58 } 59 } 60 61 extern unsigned int bch_cutoff_writeback; 62 extern unsigned int bch_cutoff_writeback_sync; 63 64 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio, 65 unsigned int cache_mode, bool would_skip) 66 { 67 unsigned int in_use = dc->disk.c->gc_stats.in_use; 68 69 if (cache_mode != CACHE_MODE_WRITEBACK || 70 test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) || 71 in_use > bch_cutoff_writeback_sync) 72 return false; 73 74 if (bio_op(bio) == REQ_OP_DISCARD) 75 return false; 76 77 if (dc->partial_stripes_expensive && 78 bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector, 79 bio_sectors(bio))) 80 return true; 81 82 if (would_skip) 83 return false; 84 85 return (op_is_sync(bio->bi_opf) || 86 bio->bi_opf & (REQ_META|REQ_PRIO) || 87 in_use <= bch_cutoff_writeback); 88 } 89 90 static inline void bch_writeback_queue(struct cached_dev *dc) 91 { 92 if (!IS_ERR_OR_NULL(dc->writeback_thread)) 93 wake_up_process(dc->writeback_thread); 94 } 95 96 static inline void bch_writeback_add(struct cached_dev *dc) 97 { 98 if (!atomic_read(&dc->has_dirty) && 99 !atomic_xchg(&dc->has_dirty, 1)) { 100 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) { 101 SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY); 102 /* XXX: should do this synchronously */ 103 bch_write_bdev_super(dc, NULL); 104 } 105 106 bch_writeback_queue(dc); 107 } 108 } 109 110 void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode, 111 uint64_t offset, int nr_sectors); 112 113 void bch_sectors_dirty_init(struct bcache_device *d); 114 void bch_cached_dev_writeback_init(struct cached_dev *dc); 115 int bch_cached_dev_writeback_start(struct cached_dev *dc); 116 117 #endif 118