Commit c09245f6 authored by Baolin Wang's avatar Baolin Wang Committed by Jens Axboe
Browse files

blk-iocost: Move the usage ratio calculation to the correct place 



We only use the hweight based usage ratio to calculate the new
hweight_inuse of the iocg to decide if this iocg can donate some
surplus vtime.

Thus move the usage ratio calculation to the correct place to
avoid unnecessary calculation for some vtime shortage iocgs.

Signed-off-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 647c9f03

block/blk-iocost.c

+23 −21
Original line number Diff line number Diff line
@@ -2168,8 +2168,8 @@ static void ioc_timer_fn(struct timer_list *timer) 


	/* calc usage and see whether some weights need to be moved around */

	list_for_each_entry(iocg, &ioc->active_iocgs, active_list) {

		u64 vdone, vtime, usage_us, usage_dur;

		u32 usage, hw_active, hw_inuse;

		u64 vdone, vtime, usage_us;

		u32 hw_active, hw_inuse;



		/*

		 * Collect unused and wind vtime closer to vnow to prevent
@@ -2200,10 +2200,19 @@ static void ioc_timer_fn(struct timer_list *timer) 
		usage_us = iocg->usage_delta_us;

		usage_us_sum += usage_us;



		/* see whether there's surplus vtime */

		WARN_ON_ONCE(!list_empty(&iocg->surplus_list));

		if (hw_inuse < hw_active ||

		    (!waitqueue_active(&iocg->waitq) &&

		     time_before64(vtime, now.vnow - ioc->margins.low))) {

			u32 hwa, old_hwi, hwm, new_hwi, usage;

			u64 usage_dur;



			if (vdone != vtime) {

				u64 inflight_us = DIV64_U64_ROUND_UP(

					cost_to_abs_cost(vtime - vdone, hw_inuse),

					ioc->vtime_base_rate);



				usage_us = max(usage_us, inflight_us);

			}
@@ -2218,13 +2227,6 @@ static void ioc_timer_fn(struct timer_list *timer) 
						   usage_dur),

				1, WEIGHT_ONE);



		/* see whether there's surplus vtime */

		WARN_ON_ONCE(!list_empty(&iocg->surplus_list));

		if (hw_inuse < hw_active ||

		    (!waitqueue_active(&iocg->waitq) &&

		     time_before64(vtime, now.vnow - ioc->margins.low))) {

			u32 hwa, old_hwi, hwm, new_hwi;



			/*

			 * Already donating or accumulated enough to start.

			 * Determine the donation amount.

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