linux-kernel - [RFC PATCH] sched/fair: Prevent from cpufreq not being updated when delayed-task is iowait

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250226114301.4900-1-xuewen.yan@unisoc.com>
Date: Wed, 26 Feb 2025 19:43:01 +0800
From: Xuewen Yan <xuewen.yan@...soc.com>
To: <peterz@...radead.org>, <mingo@...hat.com>, <juri.lelli@...hat.com>,
        <vincent.guittot@...aro.org>, <dietmar.eggemann@....com>
CC: <rostedt@...dmis.org>, <bsegall@...gle.com>, <mgorman@...e.de>,
        <vschneid@...hat.com>, <ke.wang@...soc.com>, <di.shen@...soc.com>,
        <xuewen.yan94@...il.com>, <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH] sched/fair: Prevent from cpufreq not being updated when delayed-task is iowait

Because the sched-delayed task maybe in io-wait state,
so we should place the requeue_delayed_entity() after the
cpufreq_update_util(), to prevent not boosting iowait cpufreq
before return.

Signed-off-by: Xuewen Yan <xuewen.yan@...soc.com>
---
 kernel/sched/fair.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2d6d5582c3e9..040674734128 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6931,11 +6931,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 	if (!(p->se.sched_delayed && (task_on_rq_migrating(p) || (flags & ENQUEUE_RESTORE))))
 		util_est_enqueue(&rq->cfs, p);
 
-	if (flags & ENQUEUE_DELAYED) {
-		requeue_delayed_entity(se);
-		return;
-	}
-
 	/*
 	 * If in_iowait is set, the code below may not trigger any cpufreq
 	 * utilization updates, so do it here explicitly with the IOWAIT flag
@@ -6944,6 +6939,11 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 	if (p->in_iowait)
 		cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT);
 
+	if (flags & ENQUEUE_DELAYED) {
+		requeue_delayed_entity(se);
+		return;
+	}
+
 	if (task_new && se->sched_delayed)
 		h_nr_runnable = 0;
 
-- 
2.25.1