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[5/7] x86/tsc: Update cpufreq transition notifier to handle multiple CPUs

Message ID 8a27342332bc467242f6ccdb4d4bd4d10f8aa552.1552545525.git.viresh.kumar@linaro.org
State New
Headers show
Series [1/7] cpufreq: Pass policy->related_cpus to transition notifiers | expand

Commit Message

Viresh Kumar March 14, 2019, 6:42 a.m. UTC 
The cpufreq core currently calls the cpufreq transition notifier
callback once for each affected CPU. This is going to change soon and
the cpufreq core will call the callback only once for each cpufreq
policy. The callback must look at the newly added field in struct
cpufreq_freqs, "cpus", which contains policy->related_cpus (both
online/offline CPUs) and perform per-cpu actions for them if any.

This patch updates time_cpufreq_notifier() to use the new "cpus" field,
update per-cpu data for all the related CPUs and call set_cyc2ns_scale()
for all online related_cpus.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

---
 arch/x86/kernel/tsc.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

-- 
2.21.0.rc0.269.g1a574e7a288b
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Patch

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 3fae23834069..587a6aa72f38 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -956,28 +956,37 @@  static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 				void *data)
 {
 	struct cpufreq_freqs *freq = data;
-	unsigned long *lpj;
-
-	lpj = &boot_cpu_data.loops_per_jiffy;
-#ifdef CONFIG_SMP
-	if (!(freq->flags & CPUFREQ_CONST_LOOPS))
-		lpj = &cpu_data(freq->cpu).loops_per_jiffy;
-#endif
+	bool boot_cpu = !IS_ENABLED(CONFIG_SMP) || freq->flags & CPUFREQ_CONST_LOOPS;
+	unsigned long lpj;
+	int cpu;
 
 	if (!ref_freq) {
 		ref_freq = freq->old;
-		loops_per_jiffy_ref = *lpj;
 		tsc_khz_ref = tsc_khz;
+
+		if (boot_cpu)
+			loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
+		else
+			loops_per_jiffy_ref = cpu_data(cpumask_first(freq->cpus)).loops_per_jiffy;
 	}
+
 	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
 			(val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
-		*lpj = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
-
+		lpj = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
 		tsc_khz = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new);
+
 		if (!(freq->flags & CPUFREQ_CONST_LOOPS))
 			mark_tsc_unstable("cpufreq changes");
 
-		set_cyc2ns_scale(tsc_khz, freq->cpu, rdtsc());
+		if (boot_cpu) {
+			boot_cpu_data.loops_per_jiffy = lpj;
+		} else {
+			for_each_cpu(cpu, freq->cpus)
+				cpu_data(cpu).loops_per_jiffy = lpj;
+		}
+
+		for_each_cpu_and(cpu, freq->cpus, cpu_online_mask)
+			set_cyc2ns_scale(tsc_khz, cpu, rdtsc());
 	}
 
 	return 0;