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: Baolin Wang <[email protected]> Acked-by: Tejun Heo <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
vieko · Dec 7, 2020 · c09245f · c09245f
1 parent 647c9f0
commit c09245f
Showing 1 changed file with 23 additions and 21 deletions.
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
@@ -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
@@ -2200,30 +2200,32 @@ static void ioc_timer_fn(struct timer_list *timer)
 		usage_us = iocg->usage_delta_us;
 		usage_us_sum += usage_us;
 
-		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);
-		}
-
-		/* convert to hweight based usage ratio */
-		if (time_after64(iocg->activated_at, ioc->period_at))
-			usage_dur = max_t(u64, now.now - iocg->activated_at, 1);
-		else
-			usage_dur = max_t(u64, now.now - ioc->period_at, 1);
-
-		usage = clamp_t(u32,
-				DIV64_U64_ROUND_UP(usage_us * WEIGHT_ONE,
-						   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;
+			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);
+			}
+
+			/* convert to hweight based usage ratio */
+			if (time_after64(iocg->activated_at, ioc->period_at))
+				usage_dur = max_t(u64, now.now - iocg->activated_at, 1);
+			else
+				usage_dur = max_t(u64, now.now - ioc->period_at, 1);
+
+			usage = clamp_t(u32,
+				DIV64_U64_ROUND_UP(usage_us * WEIGHT_ONE,
+						   usage_dur),
+				1, WEIGHT_ONE);
 
 			/*
 			 * Already donating or accumulated enough to start.