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Date: Thu, 16 Jul 2015 21:17:06 +0300
From: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To: linux-pm@...r.kernel.org, "Rafael J. Wysocki" <rjw@...ysocki.net>,
linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
Kristen Carlson Accardi <kristen@...ux.intel.com>,
Len Brown <lenb@...nel.org>
Cc: Ethan Zhao <ethan.zhao@...cle.com>
Subject: [PATCH RFC] intel_pstate: play well with frequency limits set by
acpi
IPMI can control CPU P-states remotely: configuration is reported via
common ACPI interface (_PPC/_PSS/etc). This patch adds required minimal
support in intel_pstate to receive and use these P-state limits.
* ignore limit of top state in _PPC: it lower than turbo boost frequency
* register intel_pstate in acpi-processor to get states from _PSS
* link acpi_processor_get_bios_limit: this adds attribute "bios_limit"
Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
drivers/acpi/processor_perflib.c | 3 +-
drivers/cpufreq/intel_pstate.c | 57 ++++++++++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index cfc8aba72f86..781e328c9d5f 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -98,7 +98,8 @@ static int acpi_processor_ppc_notifier(struct notifier_block *nb,
ppc = (unsigned int)pr->performance_platform_limit;
- if (ppc >= pr->performance->state_count)
+ /* Ignore limit of top state: it lower than turbo boost frequency */
+ if (!ppc || ppc >= pr->performance->state_count)
goto out;
cpufreq_verify_within_limits(policy, 0,
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 15ada47bb720..4a34ddf4fa73 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -26,6 +26,7 @@
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/acpi.h>
+#include <acpi/processor.h>
#include <linux/vmalloc.h>
#include <trace/events/power.h>
@@ -113,6 +114,9 @@ struct cpudata {
u64 prev_mperf;
u64 prev_tsc;
struct sample sample;
+#ifdef CONFIG_ACPI_PROCESSOR
+ struct acpi_processor_performance acpi_data;
+#endif
};
static struct cpudata **all_cpu_data;
@@ -145,6 +149,7 @@ static int hwp_active;
struct perf_limits {
int no_turbo;
+ int no_acpi;
int turbo_disabled;
int max_perf_pct;
int min_perf_pct;
@@ -158,6 +163,7 @@ struct perf_limits {
static struct perf_limits limits = {
.no_turbo = 0,
+ .no_acpi = !IS_ENABLED(CONFIG_ACPI_PROCESSOR),
.turbo_disabled = 0,
.max_perf_pct = 100,
.max_perf = int_tofp(1),
@@ -449,6 +455,18 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b,
return count;
}
+static ssize_t store_no_acpi(struct kobject *a, struct attribute *b,
+ const char *buf, size_t count)
+{
+#ifdef CONFIG_ACPI_PROCESSOR
+ return kstrtouint(buf, 0, &limits.no_acpi) ?: count;
+#else
+ return -ENODEV;
+#endif
+}
+show_one(no_acpi, no_acpi);
+define_one_global_rw(no_acpi);
+
show_one(max_perf_pct, max_perf_pct);
show_one(min_perf_pct, min_perf_pct);
@@ -460,6 +478,7 @@ define_one_global_ro(num_pstates);
static struct attribute *intel_pstate_attributes[] = {
&no_turbo.attr,
+ &no_acpi.attr,
&max_perf_pct.attr,
&min_perf_pct.attr,
&turbo_pct.attr,
@@ -1049,6 +1068,38 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
cpumask_set_cpu(policy->cpu, policy->cpus);
+#ifdef CONFIG_ACPI_PROCESSOR
+ if (!limits.no_acpi) {
+ /*
+ * Minimum necessary to get acpi_processor_ppc_notifier() and
+ * acpi_processor_get_bios_limit() working.
+ */
+ if (!zalloc_cpumask_var(&cpu->acpi_data.shared_cpu_map,
+ GFP_KERNEL))
+ rc = -ENOMEM;
+ else
+ rc = acpi_processor_register_performance(
+ &cpu->acpi_data, policy->cpu);
+ if (rc) {
+ pr_err("intel_pstate: acpi init failed: %d\n", rc);
+ free_cpumask_var(cpu->acpi_data.shared_cpu_map);
+ limits.no_acpi = 1;
+ }
+ }
+#endif
+ return 0;
+}
+
+static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
+{
+#ifdef CONFIG_ACPI_PROCESSOR
+ struct cpudata *cpu = all_cpu_data[policy->cpu];
+
+ if (cpu->acpi_data.state_count)
+ acpi_processor_unregister_performance(&cpu->acpi_data,
+ policy->cpu);
+ free_cpumask_var(cpu->acpi_data.shared_cpu_map);
+#endif
return 0;
}
@@ -1057,7 +1108,11 @@ static struct cpufreq_driver intel_pstate_driver = {
.verify = intel_pstate_verify_policy,
.setpolicy = intel_pstate_set_policy,
.get = intel_pstate_get,
+#ifdef CONFIG_ACPI_PROCESSOR
+ .bios_limit = acpi_processor_get_bios_limit,
+#endif
.init = intel_pstate_cpu_init,
+ .exit = intel_pstate_cpu_exit,
.stop_cpu = intel_pstate_stop_cpu,
.name = "intel_pstate",
};
@@ -1286,6 +1341,8 @@ static int __init intel_pstate_setup(char *str)
force_load = 1;
if (!strcmp(str, "hwp_only"))
hwp_only = 1;
+ if (!strcmp(str, "no_acpi"))
+ limits.no_acpi = 1;
return 0;
}
early_param("intel_pstate", intel_pstate_setup);
--
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