[PATCH v1] cpufreq: intel_pstate: Rearrange locking in hybrid_init_cpu_capacity_scaling()

From: Rafael J. Wysocki
Date: Thu Nov 07 2024 - 07:36:29 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Notice that hybrid_init_cpu_capacity_scaling() only needs to hold
hybrid_capacity_lock around __hybrid_init_cpu_capacity_scaling()
calls, so introduce a "locked" wrapper around the latter and call
it from the former. This allows to drop a local variable and a
label that are not needed any more.

Also, rename __hybrid_init_cpu_capacity_scaling() to
__hybrid_refresh_cpu_capacity_scaling() for consistency.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---

This is on top of

https://lore.kernel.org/linux-pm/12555220.O9o76ZdvQC@xxxxxxxxxxxxx/

---
drivers/cpufreq/intel_pstate.c | 35 ++++++++++++++++-------------------
1 file changed, 16 insertions(+), 19 deletions(-)

Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1028,26 +1028,29 @@ static void hybrid_update_cpu_capacity_s
}
}

-static void __hybrid_init_cpu_capacity_scaling(void)
+static void __hybrid_refresh_cpu_capacity_scaling(void)
{
hybrid_max_perf_cpu = NULL;
hybrid_update_cpu_capacity_scaling();
}

-static void hybrid_init_cpu_capacity_scaling(bool refresh)
+static void hybrid_refresh_cpu_capacity_scaling(void)
{
- bool disable_itmt = false;
+ guard(mutex)(&hybrid_capacity_lock);

- mutex_lock(&hybrid_capacity_lock);
+ __hybrid_refresh_cpu_capacity_scaling();
+}

+static void hybrid_init_cpu_capacity_scaling(bool refresh)
+{
/*
* If hybrid_max_perf_cpu is set at this point, the hybrid CPU capacity
* scaling has been enabled already and the driver is just changing the
* operation mode.
*/
if (refresh) {
- __hybrid_init_cpu_capacity_scaling();
- goto unlock;
+ hybrid_refresh_cpu_capacity_scaling();
+ return;
}

/*
@@ -1056,19 +1059,13 @@ static void hybrid_init_cpu_capacity_sca
* do not do that when SMT is in use.
*/
if (hwp_is_hybrid && !sched_smt_active() && arch_enable_hybrid_capacity_scale()) {
- __hybrid_init_cpu_capacity_scaling();
- disable_itmt = true;
- }
-
-unlock:
- mutex_unlock(&hybrid_capacity_lock);
-
- /*
- * Disabling ITMT causes sched domains to be rebuilt to disable asym
- * packing and enable asym capacity.
- */
- if (disable_itmt)
+ hybrid_refresh_cpu_capacity_scaling();
+ /*
+ * Disabling ITMT causes sched domains to be rebuilt to disable asym
+ * packing and enable asym capacity.
+ */
sched_clear_itmt_support();
+ }
}

static bool hybrid_clear_max_perf_cpu(void)
@@ -1404,7 +1401,7 @@ static void intel_pstate_update_limits_f
mutex_lock(&hybrid_capacity_lock);

if (hybrid_max_perf_cpu)
- __hybrid_init_cpu_capacity_scaling();
+ __hybrid_refresh_cpu_capacity_scaling();

mutex_unlock(&hybrid_capacity_lock);
}