From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Doug Smythies <dsmythies@telus.net>
Subject: [PATCH 3/4] cpufreq: intel_pstate: Add ->offline and ->online callbacks
Date: Thu, 20 Aug 2020 18:38:01 +0200 [thread overview]
Message-ID: <1879185.C8Vd3vmt8n@kreacher> (raw)
In-Reply-To: <2283366.Lr8yYYnyev@kreacher>
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Add ->offline and ->online driver callbacksto to do the cleanup
before taking a CPU offline and to restore its working configuration
when it goes back online, respectively, to avoid invoking the ->init
callback on every CPU online which is quite a bit of unnecessary
overhead.
Define ->offline and ->online so that they can be used in the
passive as well as in the active mode and because ->offline will
do the majority of ->stop_cpu work, the passive mode does not
need that callback any more, so drop it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/intel_pstate.c | 38 ++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 3d18934fa975..aca0587b176f 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2297,28 +2297,51 @@ static int intel_pstate_verify_policy(struct cpufreq_policy_data *policy)
return 0;
}
-static void intel_cpufreq_stop_cpu(struct cpufreq_policy *policy)
+static int intel_pstate_cpu_offline(struct cpufreq_policy *policy)
{
+ pr_debug("CPU %d going offline\n", policy->cpu);
+
+ intel_pstate_exit_perf_limits(policy);
+
+ /*
+ * If the CPU is an SMT thread and it goes offline with the performance
+ * settings different from the minimum, it will prevent its sibling
+ * from getting to lower performance levels, so force the minimum
+ * performance on CPU offline to prevent that form happening.
+ */
if (hwp_active)
intel_pstate_hwp_force_min_perf(policy->cpu);
else
intel_pstate_set_min_pstate(all_cpu_data[policy->cpu]);
+
+ return 0;
+}
+
+static int intel_pstate_cpu_online(struct cpufreq_policy *policy)
+{
+ pr_debug("CPU %d going online\n", policy->cpu);
+
+ intel_pstate_init_acpi_perf_limits(policy);
+
+ if (hwp_active)
+ wrmsrl_on_cpu(policy->cpu, MSR_HWP_REQUEST,
+ all_cpu_data[policy->cpu]->hwp_req_cached);
+
+ return 0;
}
static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
{
- pr_debug("CPU %d exiting\n", policy->cpu);
+ pr_debug("CPU %d stopping\n", policy->cpu);
intel_pstate_clear_update_util_hook(policy->cpu);
if (hwp_active)
intel_pstate_hwp_save_state(policy);
-
- intel_cpufreq_stop_cpu(policy);
}
static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
{
- intel_pstate_exit_perf_limits(policy);
+ pr_debug("CPU %d exiting\n", policy->cpu);
policy->fast_switch_possible = false;
@@ -2398,6 +2421,8 @@ static struct cpufreq_driver intel_pstate = {
.init = intel_pstate_cpu_init,
.exit = intel_pstate_cpu_exit,
.stop_cpu = intel_pstate_stop_cpu,
+ .offline = intel_pstate_cpu_offline,
+ .online = intel_pstate_cpu_online,
.update_limits = intel_pstate_update_limits,
.name = "intel_pstate",
};
@@ -2652,7 +2677,8 @@ static struct cpufreq_driver intel_cpufreq = {
.fast_switch = intel_cpufreq_fast_switch,
.init = intel_cpufreq_cpu_init,
.exit = intel_cpufreq_cpu_exit,
- .stop_cpu = intel_cpufreq_stop_cpu,
+ .offline = intel_pstate_cpu_offline,
+ .online = intel_pstate_cpu_online,
.update_limits = intel_pstate_update_limits,
.name = "intel_cpufreq",
};
--
2.26.2
next prev parent reply other threads:[~2020-08-20 16:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 16:35 [PATCH 0/4] cpufreq: intel_pstate: Address some HWP-related oddities Rafael J. Wysocki
2020-08-20 16:36 ` [PATCH 1/4] cpufreq: intel_pstate: Refuse to turn off with HWP enabled Rafael J. Wysocki
2020-08-20 16:37 ` [PATCH 2/4] cpufreq: intel_pstate: Always return last EPP value from sysfs Rafael J. Wysocki
2020-08-20 16:38 ` Rafael J. Wysocki [this message]
2020-08-22 0:47 ` [PATCH 3/4] cpufreq: intel_pstate: Add ->offline and ->online callbacks Doug Smythies
2020-08-24 13:40 ` [PATCH v2 " Rafael J. Wysocki
2020-08-20 16:38 ` [PATCH 4/4] cpufreq: intel_pstate: Free memory only when turning off Rafael J. Wysocki
2020-08-22 0:47 ` [PATCH 0/4] cpufreq: intel_pstate: Address some HWP-related oddities Doug Smythies
2020-08-24 14:06 ` Rafael J. Wysocki
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