From: Tang Junhui Date: Mon, 8 Jan 2018 20:21:22 +0000 (-0800) Subject: bcache: fix wrong return value in bch_debug_init() X-Git-Tag: v4.19~1763^2~82 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=539d39eb27083405b82b9e604e88af01a9a46c63;p=platform%2Fkernel%2Flinux-rpi.git bcache: fix wrong return value in bch_debug_init() in bch_debug_init(), ret is always 0, and the return value is useless, change it to return 0 if be success after calling debugfs_create_dir(), else return a non-zero value. Signed-off-by: Tang Junhui Reviewed-by: Michael Lyle Signed-off-by: Jens Axboe --- diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 843877e..1784e50 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -323,12 +323,6 @@ struct cached_dev { struct bch_ratelimit writeback_rate; struct delayed_work writeback_rate_update; - /* - * Internal to the writeback code, so read_dirty() can keep track of - * where it's at. - */ - sector_t last_read; - /* Limit number of writeback bios in flight */ struct semaphore in_flight; struct task_struct *writeback_thread; diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c index 879ab21..af89408 100644 --- a/drivers/md/bcache/debug.c +++ b/drivers/md/bcache/debug.c @@ -251,8 +251,7 @@ void bch_debug_exit(void) int __init bch_debug_init(struct kobject *kobj) { - int ret = 0; - debug = debugfs_create_dir("bcache", NULL); - return ret; + + return IS_ERR_OR_NULL(debug); } diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index 1ac2af61..4790959 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -237,7 +237,9 @@ static void read_dirty_submit(struct closure *cl) static void read_dirty(struct cached_dev *dc) { unsigned delay = 0; - struct keybuf_key *w; + struct keybuf_key *next, *keys[MAX_WRITEBACKS_IN_PASS], *w; + size_t size; + int nk, i; struct dirty_io *io; struct closure cl; @@ -248,45 +250,87 @@ static void read_dirty(struct cached_dev *dc) * mempools. */ - while (!kthread_should_stop()) { - - w = bch_keybuf_next(&dc->writeback_keys); - if (!w) - break; - - BUG_ON(ptr_stale(dc->disk.c, &w->key, 0)); - - if (KEY_START(&w->key) != dc->last_read || - jiffies_to_msecs(delay) > 50) - while (!kthread_should_stop() && delay) - delay = schedule_timeout_interruptible(delay); - - dc->last_read = KEY_OFFSET(&w->key); - - io = kzalloc(sizeof(struct dirty_io) + sizeof(struct bio_vec) - * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), - GFP_KERNEL); - if (!io) - goto err; - - w->private = io; - io->dc = dc; - - dirty_init(w); - bio_set_op_attrs(&io->bio, REQ_OP_READ, 0); - io->bio.bi_iter.bi_sector = PTR_OFFSET(&w->key, 0); - bio_set_dev(&io->bio, PTR_CACHE(dc->disk.c, &w->key, 0)->bdev); - io->bio.bi_end_io = read_dirty_endio; - - if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL)) - goto err_free; - - trace_bcache_writeback(&w->key); + next = bch_keybuf_next(&dc->writeback_keys); + + while (!kthread_should_stop() && next) { + size = 0; + nk = 0; + + do { + BUG_ON(ptr_stale(dc->disk.c, &next->key, 0)); + + /* + * Don't combine too many operations, even if they + * are all small. + */ + if (nk >= MAX_WRITEBACKS_IN_PASS) + break; + + /* + * If the current operation is very large, don't + * further combine operations. + */ + if (size >= MAX_WRITESIZE_IN_PASS) + break; + + /* + * Operations are only eligible to be combined + * if they are contiguous. + * + * TODO: add a heuristic willing to fire a + * certain amount of non-contiguous IO per pass, + * so that we can benefit from backing device + * command queueing. + */ + if ((nk != 0) && bkey_cmp(&keys[nk-1]->key, + &START_KEY(&next->key))) + break; + + size += KEY_SIZE(&next->key); + keys[nk++] = next; + } while ((next = bch_keybuf_next(&dc->writeback_keys))); + + /* Now we have gathered a set of 1..5 keys to write back. */ + for (i = 0; i < nk; i++) { + w = keys[i]; + + io = kzalloc(sizeof(struct dirty_io) + + sizeof(struct bio_vec) * + DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), + GFP_KERNEL); + if (!io) + goto err; + + w->private = io; + io->dc = dc; + + dirty_init(w); + bio_set_op_attrs(&io->bio, REQ_OP_READ, 0); + io->bio.bi_iter.bi_sector = PTR_OFFSET(&w->key, 0); + bio_set_dev(&io->bio, + PTR_CACHE(dc->disk.c, &w->key, 0)->bdev); + io->bio.bi_end_io = read_dirty_endio; + + if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL)) + goto err_free; + + trace_bcache_writeback(&w->key); + + down(&dc->in_flight); + + /* We've acquired a semaphore for the maximum + * simultaneous number of writebacks; from here + * everything happens asynchronously. + */ + closure_call(&io->cl, read_dirty_submit, NULL, &cl); + } - down(&dc->in_flight); - closure_call(&io->cl, read_dirty_submit, NULL, &cl); + delay = writeback_delay(dc, size); - delay = writeback_delay(dc, KEY_SIZE(&w->key)); + while (!kthread_should_stop() && delay) { + schedule_timeout_interruptible(delay); + delay = writeback_delay(dc, 0); + } } if (0) { diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h index a9e3ffb..6d26927 100644 --- a/drivers/md/bcache/writeback.h +++ b/drivers/md/bcache/writeback.h @@ -5,6 +5,9 @@ #define CUTOFF_WRITEBACK 40 #define CUTOFF_WRITEBACK_SYNC 70 +#define MAX_WRITEBACKS_IN_PASS 5 +#define MAX_WRITESIZE_IN_PASS 5000 /* *512b */ + static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d) { uint64_t i, ret = 0;