linux-kernel - Re: [PATCH linux-next] sched/psi: Avoid update triggers and rtpoll

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Date:   Thu, 14 Sep 2023 13:53:49 +0800 (CST)
From:   <yang.yang29@....com.cn>
To:     <surenb@...gle.com>
Cc:     <hannes@...xchg.org>, <mingo@...hat.com>,
        <linux-kernel@...r.kernel.org>, <juri.lelli@...hat.com>,
        <yang.yang29@....com.cn>
Subject: Re: [PATCH linux-next] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary

Please see this version, thanks.

---
 kernel/sched/psi.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 81fca77397f6..3fe96d77f275 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -434,7 +434,7 @@ static u64 window_update(struct psi_window *win, u64 now, u64 value)
 	return growth;
 }

-static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
+static void update_triggers(struct psi_group *group, u64 now, bool *update_total,
 						   enum psi_aggregators aggregator)
 {
 	struct psi_trigger *t;
@@ -499,8 +499,6 @@ static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total,
 		/* Reset threshold breach flag once event got generated */
 		t->pending_event = false;
 	}
-
-	return now + group->rtpoll_min_period;
 }

 static u64 update_averages(struct psi_group *group, u64 now)
@@ -702,10 +700,14 @@ static void psi_rtpoll_work(struct psi_group *group)
 	}

 	if (now >= group->rtpoll_next_update) {
-		group->rtpoll_next_update = update_triggers(group, now, &update_total, PSI_POLL);
-		if (update_total)
-			memcpy(group->rtpoll_total, group->total[PSI_POLL],
-				   sizeof(group->rtpoll_total));
+		group->rtpoll_next_update = now + group->rtpoll_min_period;
+
+		if (changed_states & group->rtpoll_states) {
+			update_triggers(group, now, &update_total, PSI_POLL);
+			if (update_total)
+				memcpy(group->rtpoll_total, group->total[PSI_POLL],
+					   sizeof(group->rtpoll_total));
+		}
 	}

 	psi_schedule_rtpoll_work(group,
-- 
2.25.1