From 297252c81de8043ca6c36e5984c24fdb5aab9013 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Sun, 25 Jul 2010 14:29:15 +0300 Subject: writeback: do not lose wake-ups in bdi threads Currently, bdi threads ('bdi_writeback_thread()') can lose wake-ups. For example, if 'bdi_queue_work()' is executed after the bdi thread have had finished 'wb_do_writeback()' but before it called 'schedule_timeout_interruptible()'. To fix this issue, we have to check whether we have works to process after we have changed the task state to 'TASK_INTERRUPTIBLE'. This patch also clean-ups handling of the cases when 'dirty_writeback_interval' is zero or non-zero. Additionally, this patch also removes unneeded 'list_empty_careful()' call. Signed-off-by: Artem Bityutskiy Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 002be0f..05444ea 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -848,17 +848,18 @@ int bdi_writeback_thread(void *data) break; } - if (dirty_writeback_interval) { - wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); - schedule_timeout_interruptible(wait_jiffies); - } else { - set_current_state(TASK_INTERRUPTIBLE); - if (list_empty_careful(&wb->bdi->work_list) && - !kthread_should_stop()) - schedule(); + set_current_state(TASK_INTERRUPTIBLE); + if (!list_empty(&bdi->work_list)) { __set_current_state(TASK_RUNNING); + continue; } + if (dirty_writeback_interval) { + wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); + schedule_timeout(wait_jiffies); + } else + schedule(); + try_to_freeze(); } -- cgit v1.1