diff options
| -rw-r--r-- | drivers/md/bcache/bcache.h | 7 | ||||
| -rw-r--r-- | drivers/md/bcache/util.c | 11 | ||||
| -rw-r--r-- | drivers/md/bcache/util.h | 12 | ||||
| -rw-r--r-- | drivers/md/bcache/writeback.c | 43 |
4 files changed, 43 insertions, 30 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index b39f6f0b45f2..0f12382aa35d 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -498,7 +498,7 @@ struct cached_dev { */ atomic_t has_dirty; - struct ratelimit writeback_rate; + struct bch_ratelimit writeback_rate; struct delayed_work writeback_rate_update; /* @@ -507,10 +507,9 @@ struct cached_dev { */ sector_t last_read; - /* Number of writeback bios in flight */ - atomic_t in_flight; + /* Limit number of writeback bios in flight */ + struct semaphore in_flight; struct closure_with_timer writeback; - struct closure_waitlist writeback_wait; struct keybuf writeback_keys; diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c index 98eb81159a22..420dad545c7d 100644 --- a/drivers/md/bcache/util.c +++ b/drivers/md/bcache/util.c @@ -190,7 +190,16 @@ void bch_time_stats_update(struct time_stats *stats, uint64_t start_time) stats->last = now ?: 1; } -unsigned bch_next_delay(struct ratelimit *d, uint64_t done) +/** + * bch_next_delay() - increment @d by the amount of work done, and return how + * long to delay until the next time to do some work. + * + * @d - the struct bch_ratelimit to update + * @done - the amount of work done, in arbitrary units + * + * Returns the amount of time to delay by, in jiffies + */ +uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done) { uint64_t now = local_clock(); diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h index 1ae2a73ad85f..ea345c6896f4 100644 --- a/drivers/md/bcache/util.h +++ b/drivers/md/bcache/util.h @@ -450,17 +450,23 @@ read_attribute(name ## _last_ ## frequency_units) (ewma) >> factor; \ }) -struct ratelimit { +struct bch_ratelimit { + /* Next time we want to do some work, in nanoseconds */ uint64_t next; + + /* + * Rate at which we want to do work, in units per nanosecond + * The units here correspond to the units passed to bch_next_delay() + */ unsigned rate; }; -static inline void ratelimit_reset(struct ratelimit *d) +static inline void bch_ratelimit_reset(struct bch_ratelimit *d) { d->next = local_clock(); } -unsigned bch_next_delay(struct ratelimit *d, uint64_t done); +uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done); #define __DIV_SAFE(n, d, zero) \ ({ \ diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index 22cbff551628..27ac51934822 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -94,11 +94,15 @@ static void update_writeback_rate(struct work_struct *work) static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors) { + uint64_t ret; + if (atomic_read(&dc->disk.detaching) || !dc->writeback_percent) return 0; - return bch_next_delay(&dc->writeback_rate, sectors * 10000000ULL); + ret = bch_next_delay(&dc->writeback_rate, sectors * 10000000ULL); + + return min_t(uint64_t, ret, HZ); } /* Background writeback */ @@ -208,7 +212,7 @@ normal_refill: up_write(&dc->writeback_lock); - ratelimit_reset(&dc->writeback_rate); + bch_ratelimit_reset(&dc->writeback_rate); /* Punt to workqueue only so we don't recurse and blow the stack */ continue_at(cl, read_dirty, dirty_wq); @@ -318,9 +322,7 @@ static void write_dirty_finish(struct closure *cl) } bch_keybuf_del(&dc->writeback_keys, w); - atomic_dec_bug(&dc->in_flight); - - closure_wake_up(&dc->writeback_wait); + up(&dc->in_flight); closure_return_with_destructor(cl, dirty_io_destructor); } @@ -349,7 +351,7 @@ static void write_dirty(struct closure *cl) closure_bio_submit(&io->bio, cl, &io->dc->disk); - continue_at(cl, write_dirty_finish, dirty_wq); + continue_at(cl, write_dirty_finish, system_wq); } static void read_dirty_endio(struct bio *bio, int error) @@ -369,7 +371,7 @@ static void read_dirty_submit(struct closure *cl) closure_bio_submit(&io->bio, cl, &io->dc->disk); - continue_at(cl, write_dirty, dirty_wq); + continue_at(cl, write_dirty, system_wq); } static void read_dirty(struct closure *cl) @@ -394,12 +396,9 @@ static void read_dirty(struct closure *cl) if (delay > 0 && (KEY_START(&w->key) != dc->last_read || - jiffies_to_msecs(delay) > 50)) { - w->private = NULL; - - closure_delay(&dc->writeback, delay); - continue_at(cl, read_dirty, dirty_wq); - } + jiffies_to_msecs(delay) > 50)) + while (delay) + delay = schedule_timeout(delay); dc->last_read = KEY_OFFSET(&w->key); @@ -424,15 +423,10 @@ static void read_dirty(struct closure *cl) trace_bcache_writeback(&w->key); - closure_call(&io->cl, read_dirty_submit, NULL, &dc->disk.cl); + down(&dc->in_flight); + closure_call(&io->cl, read_dirty_submit, NULL, cl); delay = writeback_delay(dc, KEY_SIZE(&w->key)); - - atomic_inc(&dc->in_flight); - - if (!closure_wait_event(&dc->writeback_wait, cl, - atomic_read(&dc->in_flight) < 64)) - continue_at(cl, read_dirty, dirty_wq); } if (0) { @@ -442,7 +436,11 @@ err: bch_keybuf_del(&dc->writeback_keys, w); } - refill_dirty(cl); + /* + * Wait for outstanding writeback IOs to finish (and keybuf slots to be + * freed) before refilling again + */ + continue_at(cl, refill_dirty, dirty_wq); } /* Init */ @@ -484,6 +482,7 @@ void bch_sectors_dirty_init(struct cached_dev *dc) void bch_cached_dev_writeback_init(struct cached_dev *dc) { + sema_init(&dc->in_flight, 64); closure_init_unlocked(&dc->writeback); init_rwsem(&dc->writeback_lock); @@ -513,7 +512,7 @@ void bch_writeback_exit(void) int __init bch_writeback_init(void) { - dirty_wq = create_singlethread_workqueue("bcache_writeback"); + dirty_wq = create_workqueue("bcache_writeback"); if (!dirty_wq) return -ENOMEM; |