2021-05-12 14:23:44

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH 1/2] cpufreq: intel_pstate: hybrid: Avoid exposing two global attributes

From: Rafael J. Wysocki <[email protected]>

The turbo_pct and num_pstates sysfs attributes represent CPU
properties that may be different for differenty types of CPUs in
a hybrid processor, so avoid exposing them in that case.

Signed-off-by: Rafael J. Wysocki <[email protected]>
---
Documentation/admin-guide/pm/intel_pstate.rst | 6 ++++++
drivers/cpufreq/intel_pstate.c | 15 +++++++++++++--
2 files changed, 19 insertions(+), 2 deletions(-)

Index: linux-pm/Documentation/admin-guide/pm/intel_pstate.rst
===================================================================
--- linux-pm.orig/Documentation/admin-guide/pm/intel_pstate.rst
+++ linux-pm/Documentation/admin-guide/pm/intel_pstate.rst
@@ -365,6 +365,9 @@ argument is passed to the kernel in the
inclusive) including both turbo and non-turbo P-states (see
`Turbo P-states Support`_).

+ This attribute is present only if the value exposed by it is the same
+ for all of the CPUs in the system.
+
The value of this attribute is not affected by the ``no_turbo``
setting described `below <no_turbo_attr_>`_.

@@ -374,6 +377,9 @@ argument is passed to the kernel in the
Ratio of the `turbo range <turbo_>`_ size to the size of the entire
range of supported P-states, in percent.

+ This attribute is present only if the value exposed by it is the same
+ for all of the CPUs in the system.
+
This attribute is read-only.

.. _no_turbo_attr:
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1365,8 +1365,6 @@ define_one_global_rw(energy_efficiency);
static struct attribute *intel_pstate_attributes[] = {
&status.attr,
&no_turbo.attr,
- &turbo_pct.attr,
- &num_pstates.attr,
NULL
};

@@ -1391,6 +1389,14 @@ static void __init intel_pstate_sysfs_ex
if (WARN_ON(rc))
return;

+ if (!boot_cpu_has(X86_FEATURE_HYBRID_CPU)) {
+ rc = sysfs_create_file(intel_pstate_kobject, &turbo_pct.attr);
+ WARN_ON(rc);
+
+ rc = sysfs_create_file(intel_pstate_kobject, &num_pstates.attr);
+ WARN_ON(rc);
+ }
+
/*
* If per cpu limits are enforced there are no global limits, so
* return without creating max/min_perf_pct attributes
@@ -1417,6 +1423,11 @@ static void __init intel_pstate_sysfs_re

sysfs_remove_group(intel_pstate_kobject, &intel_pstate_attr_group);

+ if (!boot_cpu_has(X86_FEATURE_HYBRID_CPU)) {
+ sysfs_remove_file(intel_pstate_kobject, &num_pstates.attr);
+ sysfs_remove_file(intel_pstate_kobject, &turbo_pct.attr);
+ }
+
if (!per_cpu_limits) {
sysfs_remove_file(intel_pstate_kobject, &max_perf_pct.attr);
sysfs_remove_file(intel_pstate_kobject, &min_perf_pct.attr);