lkml.org 
[lkml]   [2020]   [Jul]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] arm64: topology: Don't support AMU without cpufreq
Date
The commit cd0ed03a8903 ("arm64: use activity monitors for frequency
invariance"), mentions that:

"if CONFIG_CPU_FREQ is not enabled, the use of counters is
enabled on all CPUs only if all possible CPUs correctly support
the necessary counters"

But that's not really true as validate_cpu_freq_invariance_counters()
fails if max_freq_hz is returned as 0 (in case there is no policy for
the CPU). And the AMUs won't be supported in that case.

Make the code reflect this reality.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
arch/arm64/kernel/topology.c | 19 +++----------------
1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 0801a0f3c156..b7da372819fc 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -187,14 +187,13 @@ static int validate_cpu_freq_invariance_counters(int cpu)
return 0;
}

-static inline bool
-enable_policy_freq_counters(int cpu, cpumask_var_t valid_cpus)
+static inline void update_amu_fie_cpus(int cpu, cpumask_var_t valid_cpus)
{
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);

if (!policy) {
pr_debug("CPU%d: No cpufreq policy found.\n", cpu);
- return false;
+ return;
}

if (cpumask_subset(policy->related_cpus, valid_cpus))
@@ -202,8 +201,6 @@ enable_policy_freq_counters(int cpu, cpumask_var_t valid_cpus)
amu_fie_cpus);

cpufreq_cpu_put(policy);
-
- return true;
}

static DEFINE_STATIC_KEY_FALSE(amu_fie_key);
@@ -212,7 +209,6 @@ static DEFINE_STATIC_KEY_FALSE(amu_fie_key);
static int __init init_amu_fie(void)
{
cpumask_var_t valid_cpus;
- bool have_policy = false;
int ret = 0;
int cpu;

@@ -228,18 +224,9 @@ static int __init init_amu_fie(void)
if (validate_cpu_freq_invariance_counters(cpu))
continue;
cpumask_set_cpu(cpu, valid_cpus);
- have_policy |= enable_policy_freq_counters(cpu, valid_cpus);
+ update_amu_fie_cpus(cpu, valid_cpus);
}

- /*
- * If we are not restricted by cpufreq policies, we only enable
- * the use of the AMU feature for FIE if all CPUs support AMU.
- * Otherwise, enable_policy_freq_counters has already enabled
- * policy cpus.
- */
- if (!have_policy && cpumask_equal(valid_cpus, cpu_present_mask))
- cpumask_or(amu_fie_cpus, amu_fie_cpus, valid_cpus);
-
if (!cpumask_empty(amu_fie_cpus)) {
pr_info("CPUs[%*pbl]: counters will be used for FIE.",
cpumask_pr_args(amu_fie_cpus));
--
2.25.0.rc1.19.g042ed3e048af
\
 
 \ /
  Last update: 2020-07-09 08:53    [W:0.092 / U:2.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site