linux-kernel - [RFC 2/3] cpufreq: governor: Use minimum load QoS

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Message-ID: <20200526151619.8779-3-benjamin.gaignard@st.com>
Date:   Tue, 26 May 2020 17:16:18 +0200
From:   Benjamin Gaignard <benjamin.gaignard@...com>
To:     <rjw@...ysocki.net>, <viresh.kumar@...aro.org>,
        <hugues.fruchet@...com>, <mchehab@...nel.org>,
        <mcoquelin.stm32@...il.com>, <alexandre.torgue@...com>,
        <pavel@....cz>, <len.brown@...el.com>,
        <valentin.schneider@....com>, <vincent.guittot@...aro.org>
CC:     <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-media@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        Benjamin Gaignard <benjamin.gaignard@...com>
Subject: [RFC 2/3] cpufreq: governor: Use minimum load QoS

Make sure that the returned load is above the system-wide minimum
load QoS.
Devices could set this specific QoS to inform governors about their
need in terms of CPU load when computing it from idle time isn't accurate.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...com>
---
 drivers/cpufreq/cpufreq_governor.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index f99ae45efaea..1494e5e4c788 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -118,6 +118,7 @@ unsigned int dbs_update(struct cpufreq_policy *policy)
 	unsigned int ignore_nice = dbs_data->ignore_nice_load;
 	unsigned int max_load = 0, idle_periods = UINT_MAX;
 	unsigned int sampling_rate, io_busy, j;
+	unsigned int qos_min_load;
 
 	/*
 	 * Sometimes governors may use an additional multiplier to increase
@@ -225,6 +226,10 @@ unsigned int dbs_update(struct cpufreq_policy *policy)
 
 	policy_dbs->idle_periods = idle_periods;
 
+	qos_min_load = cpufreq_minload_qos_limit();
+	if (qos_min_load > max_load)
+		max_load = qos_min_load;
+
 	return max_load;
 }
 EXPORT_SYMBOL_GPL(dbs_update);
-- 
2.15.0