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From: Xuewen Yan <xuewen.yan@unisoc.com>
To: <vincent.guittot@linaro.org>, <mingo@redhat.com>, <peterz@infradead.org>,
        <juri.lelli@redhat.com>, <dietmar.eggemann@arm.com>
CC: <rostedt@goodmis.org>, <bsegall@google.com>, <mgorman@suse.de>,
        <bristot@redhat.com>, <vschneid@redhat.com>,
        <vincent.donnefort@arm.com>, <qyousef@layalina.io>,
        <ke.wang@unisoc.com>, <xuewen.yan94@gmail.com>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH] sched/fair: Prevent cpu_busy_time from exceeding actual_cpu_capacity
Date: Thu, 6 Jun 2024 15:06:45 +0800
Message-ID: <20240606070645.3295-1-xuewen.yan@unisoc.com>
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Because the effective_cpu_util() would return a util which
maybe bigger than the actual_cpu_capacity, this could cause
the pd_busy_time calculation errors.
So clamp the cpu_busy_time with the eenv->cpu_cap, which is
the actual_cpu_capacity.

Fixes: 3e8c6c9aac42 ("sched/fair: Remove task_util from effective utilization in feec()")
Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
---
 kernel/sched/fair.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8a5b1ae0aa55..8939d725023a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7870,7 +7870,9 @@ static inline void eenv_pd_busy_time(struct energy_env *eenv,
 	for_each_cpu(cpu, pd_cpus) {
 		unsigned long util = cpu_util(cpu, p, -1, 0);
 
-		busy_time += effective_cpu_util(cpu, util, NULL, NULL);
+		util = effective_cpu_util(cpu, util, NULL, NULL);
+		util = min(eenv->cpu_cap, util);
+		busy_time += util;
 	}
 
 	eenv->pd_busy_time = min(eenv->pd_cap, busy_time);
-- 
2.25.1