linux-kernel - [PATCH 2/2] cpufreq: Introduce a more generic way to set default per-policy boost flag

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Message-ID: <20250115100123.241110-3-zhenglifeng1@huawei.com>
Date: Wed, 15 Jan 2025 18:01:23 +0800
From: Lifeng Zheng <zhenglifeng1@...wei.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>
CC: <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linuxarm@...wei.com>, <jonathan.cameron@...wei.com>,
	<zhanjie9@...ilicon.com>, <lihuisong@...wei.com>, <zhenglifeng1@...wei.com>,
	<fanghao11@...wei.com>
Subject: [PATCH 2/2] cpufreq: Introduce a more generic way to set default per-policy boost flag

In cpufreq_online() of cpufreq.c, the per-policy boost flag is already set
to mirror the cpufreq_driver boost during init but using freq_table to
judge if the policy has boost frequency. There are two drawbacks to this
approach:

1. It doesn't work for the cpufreq drivers that do not use a frequency
table. For now, acpi-cpufreq and amd-pstate have to enable boost in policy
initialization. And cppc_cpufreq never set policy to boost when going
online no matter what the cpufreq_driver boost flag is.

2. If the cpu goes offline when cpufreq_driver boost enabled and then goes
online when cpufreq_driver boost disabled, the per-policy boost flag will
unreasonably remain true.

Running set_boost at the end of the online process is a more generic way
for all cpufreq drivers.

Signed-off-by: Lifeng Zheng <zhenglifeng1@...wei.com>
---
 drivers/cpufreq/cpufreq.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 03ae879d50b9..867bda3decfd 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1409,10 +1409,6 @@ static int cpufreq_online(unsigned int cpu)
 			goto out_free_policy;
 		}
 
-		/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
-		if (cpufreq_boost_enabled() && policy_has_boost_freq(policy))
-			policy->boost_enabled = true;
-
 		/*
 		 * The initialization has succeeded and the policy is online.
 		 * If there is a problem with its frequency table, take it
@@ -1576,6 +1572,18 @@ static int cpufreq_online(unsigned int cpu)
 	if (new_policy && cpufreq_thermal_control_enabled(cpufreq_driver))
 		policy->cdev = of_cpufreq_cooling_register(policy);
 
+	/* Let the per-policy boost flag mirror the cpufreq_driver boost during init */
+	if (cpufreq_boost_supported()) {
+		policy->boost_enabled = cpufreq_boost_enabled();
+		ret = cpufreq_driver->set_boost(policy, policy->boost_enabled);
+		if (ret) {
+			/* If the set_boost fails, the online operation is not affected */
+			pr_info("%s: CPU%d: Cannot %s BOOST\n", __func__, policy->cpu,
+				policy->boost_enabled ? "enable" : "disable");
+			policy->boost_enabled = !policy->boost_enabled;
+		}
+	}
+
 	pr_debug("initialization complete\n");
 
 	return 0;
-- 
2.33.0