The following commit has been merged in the linux branch: commit d25105e8911bff1dbd68e387f12901c5b1a15fe8 Author: Wu Fengguang fengguang.wu@intel.com Date: Fri Oct 9 12:40:42 2009 +0200
writeback: account IO throttling wait as iowait
It makes sense to do IOWAIT when someone is blocked due to IO throttle, as suggested by Kame and Peter.
There is an old comment for not doing IOWAIT on throttle, however it has been mismatching the code for a long time.
If we stop accounting IOWAIT for 2.6.32, it could be an undesirable behavior change. So restore the io_schedule.
CC: KAMEZAWA Hiroyuki kamezawa.hiroyu@jp.fujitsu.com CC: Peter Zijlstra a.p.zijlstra@chello.nl Signed-off-by: Wu Fengguang fengguang.wu@intel.com Signed-off-by: Jens Axboe jens.axboe@oracle.com
diff --git a/kernel/sched.c b/kernel/sched.c index 1535f38..074f753 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6720,9 +6720,6 @@ EXPORT_SYMBOL(yield); /* * This task is about to go to sleep on IO. Increment rq->nr_iowait so * that process accounting knows that this is a task in IO wait state. - * - * But don't do that if it is a deliberate, throttling IO wait (this task - * has set its backing_dev_info: the queue against which it should throttle) */ void __sched io_schedule(void) { diff --git a/mm/page-writeback.c b/mm/page-writeback.c index a3b1409..2c5d792 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -566,7 +566,8 @@ static void balance_dirty_pages(struct address_space *mapping, if (pages_written >= write_chunk) break; /* We've done our duty */
- schedule_timeout_interruptible(pause); + __set_current_state(TASK_INTERRUPTIBLE); + io_schedule_timeout(pause);
/* * Increase the delay for each loop, up to our previous