Commit 7b84b49e authored Sep 01, 2020 by Tejun Heo Committed by Jens Axboe Sep 01, 2020

blk-iocost: make iocg_kick_waitq() call iocg_kick_delay() after paying debt



iocg_kick_waitq() is the function which pays debt and iocg_kick_delay()
updates the actual delay status accordingly. If iocg_kick_delay() is not
called after iocg_kick_delay() updated debt, unnecessarily large delays can
be applied temporarily.

Let's make sure such conditions don't occur by making iocg_kick_waitq()
always call iocg_kick_delay() after paying debt.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 6ef20f78

block/blk-iocost.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1226,6 +1226,8 @@ static void iocg_kick_waitq(struct ioc_gq iocg, struct ioc_now now)
		atomic64_add(delta, &iocg->vtime);
		atomic64_add(delta, &iocg->done_vtime);
		iocg->abs_vdebt -= abs_delta;

		iocg_kick_delay(iocg, now);
		}

		/*
		@@ -1383,7 +1385,6 @@ static void ioc_timer_fn(struct timer_list *timer)
		if (waitqueue_active(&iocg->waitq) \|\| iocg->abs_vdebt) {
		/* might be oversleeping vtime / hweight changes, kick */
		iocg_kick_waitq(iocg, &now);
		iocg_kick_delay(iocg, &now);
		} else if (iocg_is_idle(iocg)) {
		/* no waiter and idle, deactivate */
		iocg->last_inuse = iocg->inuse;