From 9e5c353510b26500bd6b8309823ac9ef2837b761 Mon Sep 17 00:00:00 2001 From: Slava Pestov Date: Thu, 1 May 2014 13:48:57 -0700 Subject: bcache: fix uninterruptible sleep in writeback thread There were two issues here: - writeback thread did not start until the device first became dirty - writeback thread used uninterruptible sleep once running Without this patch I see kernel warnings printed and a load average of 1.52 after booting my test VM. With this patch the warnings are gone and the load average is near 0.00 as expected. Signed-off-by: Kent Overstreet --- drivers/md/bcache/super.c | 3 +++ drivers/md/bcache/writeback.c | 14 ++++++++++---- drivers/md/bcache/writeback.h | 3 ++- 3 files changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 3b043a04d9bd..00cc42550f34 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1042,6 +1042,9 @@ int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c) */ atomic_set(&dc->count, 1); + if (bch_cached_dev_writeback_start(dc)) + return -ENOMEM; + if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) { bch_sectors_dirty_init(dc); atomic_set(&dc->has_dirty, 1); diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index f4300e4c0114..f1986bcd1bf0 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -239,7 +239,7 @@ static void read_dirty(struct cached_dev *dc) if (KEY_START(&w->key) != dc->last_read || jiffies_to_msecs(delay) > 50) while (!kthread_should_stop() && delay) - delay = schedule_timeout_uninterruptible(delay); + delay = schedule_timeout_interruptible(delay); dc->last_read = KEY_OFFSET(&w->key); @@ -436,7 +436,7 @@ static int bch_writeback_thread(void *arg) while (delay && !kthread_should_stop() && !test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) - delay = schedule_timeout_uninterruptible(delay); + delay = schedule_timeout_interruptible(delay); } } @@ -478,7 +478,7 @@ void bch_sectors_dirty_init(struct cached_dev *dc) dc->disk.sectors_dirty_last = bcache_dev_sectors_dirty(&dc->disk); } -int bch_cached_dev_writeback_init(struct cached_dev *dc) +void bch_cached_dev_writeback_init(struct cached_dev *dc) { sema_init(&dc->in_flight, 64); init_rwsem(&dc->writeback_lock); @@ -494,14 +494,20 @@ int bch_cached_dev_writeback_init(struct cached_dev *dc) dc->writeback_rate_d_term = 30; dc->writeback_rate_p_term_inverse = 6000; + INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate); +} + +int bch_cached_dev_writeback_start(struct cached_dev *dc) +{ dc->writeback_thread = kthread_create(bch_writeback_thread, dc, "bcache_writeback"); if (IS_ERR(dc->writeback_thread)) return PTR_ERR(dc->writeback_thread); - INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate); schedule_delayed_work(&dc->writeback_rate_update, dc->writeback_rate_update_seconds * HZ); + bch_writeback_queue(dc); + return 0; } diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h index e2f8598937ac..0a9dab187b79 100644 --- a/drivers/md/bcache/writeback.h +++ b/drivers/md/bcache/writeback.h @@ -85,6 +85,7 @@ static inline void bch_writeback_add(struct cached_dev *dc) void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int); void bch_sectors_dirty_init(struct cached_dev *dc); -int bch_cached_dev_writeback_init(struct cached_dev *); +void bch_cached_dev_writeback_init(struct cached_dev *); +int bch_cached_dev_writeback_start(struct cached_dev *); #endif -- cgit v1.2.3