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Message-Id: <f4b69674ee35cbec102857218d8409249c8f26c7.1594289009.git.viresh.kumar@linaro.org>
Date: Thu, 9 Jul 2020 15:43:33 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>
Cc: Viresh Kumar <viresh.kumar@...aro.org>,
Ionela Voinescu <ionela.voinescu@....com>,
Peter Puhov <peter.puhov@...aro.org>,
Vincent Guittot <vincent.guittot@...aro.org>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [RFC 1/3] arm64: topology: Add amu_counters_supported() helper
We would need to know earlier during the boot cycle if AMUs are
supported or not for all the CPUs, export a routine for that and move
code around to make it more readable.
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
arch/arm64/kernel/topology.c | 108 ++++++++++++++++++-----------------
1 file changed, 56 insertions(+), 52 deletions(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index b7da372819fc..74fde35b56ef 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -130,6 +130,9 @@ static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale);
static DEFINE_PER_CPU(u64, arch_const_cycles_prev);
static DEFINE_PER_CPU(u64, arch_core_cycles_prev);
static cpumask_var_t amu_fie_cpus;
+static cpumask_var_t valid_cpus;
+static DEFINE_STATIC_KEY_FALSE(amu_fie_key);
+#define amu_freq_invariant() static_branch_unlikely(&amu_fie_key)
/* Initialize counter reference per-cpu variables for the current CPU */
void init_cpu_freq_invariance_counters(void)
@@ -140,26 +143,14 @@ void init_cpu_freq_invariance_counters(void)
read_sysreg_s(SYS_AMEVCNTR0_CONST_EL0));
}
-static int validate_cpu_freq_invariance_counters(int cpu)
+static void setup_freq_invariance(int cpu)
{
- u64 max_freq_hz, ratio;
-
- if (!cpu_has_amu_feat(cpu)) {
- pr_debug("CPU%d: counters are not supported.\n", cpu);
- return -EINVAL;
- }
-
- if (unlikely(!per_cpu(arch_const_cycles_prev, cpu) ||
- !per_cpu(arch_core_cycles_prev, cpu))) {
- pr_debug("CPU%d: cycle counters are not enabled.\n", cpu);
- return -EINVAL;
- }
+ struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+ u64 ratio;
- /* Convert maximum frequency from KHz to Hz and validate */
- max_freq_hz = cpufreq_get_hw_max_freq(cpu) * 1000;
- if (unlikely(!max_freq_hz)) {
- pr_debug("CPU%d: invalid maximum frequency.\n", cpu);
- return -EINVAL;
+ if (!policy) {
+ pr_debug("CPU%d: No cpufreq policy found.\n", cpu);
+ return;
}
/*
@@ -176,69 +167,75 @@ static int validate_cpu_freq_invariance_counters(int cpu)
* be unlikely).
*/
ratio = (u64)arch_timer_get_rate() << (2 * SCHED_CAPACITY_SHIFT);
- ratio = div64_u64(ratio, max_freq_hz);
+ ratio = div64_u64(ratio, policy->cpuinfo.max_freq * 1000);
if (!ratio) {
WARN_ONCE(1, "System timer frequency too low.\n");
- return -EINVAL;
+ goto out;
}
per_cpu(arch_max_freq_scale, cpu) = (unsigned long)ratio;
- return 0;
-}
-
-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;
- }
-
if (cpumask_subset(policy->related_cpus, valid_cpus))
- cpumask_or(amu_fie_cpus, policy->related_cpus,
- amu_fie_cpus);
+ cpumask_or(amu_fie_cpus, policy->related_cpus, amu_fie_cpus);
+out:
cpufreq_cpu_put(policy);
}
-static DEFINE_STATIC_KEY_FALSE(amu_fie_key);
-#define amu_freq_invariant() static_branch_unlikely(&amu_fie_key)
+bool amu_counters_supported(void)
+{
+ return likely(cpumask_available(valid_cpus)) &&
+ cpumask_equal(valid_cpus, cpu_present_mask);
+}
-static int __init init_amu_fie(void)
+static int __init early_init_amu_fie(void)
{
- cpumask_var_t valid_cpus;
- int ret = 0;
int cpu;
if (!zalloc_cpumask_var(&valid_cpus, GFP_KERNEL))
return -ENOMEM;
- if (!zalloc_cpumask_var(&amu_fie_cpus, GFP_KERNEL)) {
- ret = -ENOMEM;
- goto free_valid_mask;
- }
-
for_each_present_cpu(cpu) {
- if (validate_cpu_freq_invariance_counters(cpu))
+ if (!cpu_has_amu_feat(cpu)) {
+ pr_debug("CPU%d: counters are not supported.\n", cpu);
+ continue;
+ }
+
+ if (unlikely(!per_cpu(arch_const_cycles_prev, cpu) ||
+ !per_cpu(arch_core_cycles_prev, cpu))) {
+ pr_debug("CPU%d: cycle counters are not enabled.\n", cpu);
continue;
+ }
+
cpumask_set_cpu(cpu, valid_cpus);
- update_amu_fie_cpus(cpu, valid_cpus);
}
+ return 0;
+}
+core_initcall_sync(early_init_amu_fie);
+
+static int __init late_init_amu_fie(void)
+{
+ int cpu;
+
+ if (!cpumask_available(valid_cpus))
+ return -ENOMEM;
+
+ if (!zalloc_cpumask_var(&amu_fie_cpus, GFP_KERNEL))
+ return -ENOMEM;
+
+ for_each_present_cpu(cpu)
+ setup_freq_invariance(cpu);
+
if (!cpumask_empty(amu_fie_cpus)) {
pr_info("CPUs[%*pbl]: counters will be used for FIE.",
cpumask_pr_args(amu_fie_cpus));
static_branch_enable(&amu_fie_key);
}
-free_valid_mask:
- free_cpumask_var(valid_cpus);
-
- return ret;
+ return 0;
}
-late_initcall_sync(init_amu_fie);
+late_initcall_sync(late_init_amu_fie);
bool arch_freq_counters_available(struct cpumask *cpus)
{
@@ -272,7 +269,7 @@ void topology_scale_freq_tick(void)
* scale = ------- * --------------------
* /\const SCHED_CAPACITY_SCALE
*
- * See validate_cpu_freq_invariance_counters() for details on
+ * See setup_freq_invariance() for details on
* arch_max_freq_scale and the use of SCHED_CAPACITY_SHIFT.
*/
scale = core_cnt - prev_core_cnt;
@@ -287,4 +284,11 @@ void topology_scale_freq_tick(void)
this_cpu_write(arch_core_cycles_prev, core_cnt);
this_cpu_write(arch_const_cycles_prev, const_cnt);
}
+#else
+bool amu_counters_supported(void)
+{
+ return false;
+}
#endif /* CONFIG_ARM64_AMU_EXTN */
+
+EXPORT_SYMBOL_GPL(amu_counters_supported);
--
2.25.0.rc1.19.g042ed3e048af
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