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

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Message-ID: <202309132044261713252@zte.com.cn>
Date:   Wed, 13 Sep 2023 20:44:26 +0800 (CST)
From:   <yang.yang29@....com.cn>
To:     <hannes@...xchg.org>, <surenb@...gle.com>
Cc:     <mingo@...hat.com>, <linux-kernel@...r.kernel.org>,
        <juri.lelli@...hat.com>
Subject: [PATCH linux-next] sched/psi: Avoid update triggers and rtpoll_total when it is unnecessary

From: Yang Yang <yang.yang29@....com.cn>

When psimon wakes up and there are no state changes for rtpoll_states,
it's unnecessary to update triggers and rtpoll_total because the pressures
being monitored by user have not changed.

Signed-off-by: Yang Yang <yang.yang29@....com.cn>
---
 kernel/sched/psi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 81fca77397f6..e4463bb267c3 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -701,7 +701,7 @@ static void psi_rtpoll_work(struct psi_group *group)
 		goto out;
 	}

-	if (now >= group->rtpoll_next_update) {
+	if ((changed_states & group->rtpoll_states) && (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],
-- 
2.25.1