Merge "ARM: dts: msm: disable core_ctl for SDM630"

Documentation/kernel-parameters.txt

@@ -750,6 +750,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			seconds. Defaults to 10*60 = 10mins. A value of 0
 			disables the blank timer.
 
+	core_ctl_disable_cpumask= [SMP]
+			Exempt the CPUs from being managed by core_ctl.
+			core_ctl operates on a cluster basis. So all the
+			CPUs in a given cluster must be specified to disable
+			core_ctl for that cluster.
+
 	coredump_filter=
 			[KNL] Change the default value for
 			/proc/<pid>/coredump_filter.

arch/arm/boot/dts/qcom/sdm630.dtsi

@@ -34,7 +34,7 @@
 
 	chosen {
 		stdout-path = "serial0";
-		bootargs = "rcupdate.rcu_expedited=1";
+		bootargs = "rcupdate.rcu_expedited=1 core_ctl_disable_cpumask=0-7";
 	};
 
 	psci {

kernel/sched/core_ctl.c

@@ -653,6 +653,9 @@ int core_ctl_set_boost(bool boost)
 	int ret = 0;
 	bool boost_state_changed = false;
 
+	if (unlikely(!initialized))
+		return 0;
+
 	spin_lock_irqsave(&state_lock, flags);
 	for_each_cluster(cluster, index) {
 		if (cluster->is_big_cluster) {
@@ -931,6 +934,42 @@ static struct notifier_block __refdata cpu_notifier = {
 
 /* ============================ init code ============================== */
 
+static cpumask_var_t core_ctl_disable_cpumask;
+static bool core_ctl_disable_cpumask_present;
+
+static int __init core_ctl_disable_setup(char *str)
+{
+	if (!*str)
+		return -EINVAL;
+
+	alloc_bootmem_cpumask_var(&core_ctl_disable_cpumask);
+
+	if (cpulist_parse(str, core_ctl_disable_cpumask) < 0) {
+		free_bootmem_cpumask_var(core_ctl_disable_cpumask);
+		return -EINVAL;
+	}
+
+	core_ctl_disable_cpumask_present = true;
+	pr_info("disable_cpumask=%*pbl\n",
+			cpumask_pr_args(core_ctl_disable_cpumask));
+
+	return 0;
+}
+early_param("core_ctl_disable_cpumask", core_ctl_disable_setup);
+
+static bool should_skip(const struct cpumask *mask)
+{
+	if (!core_ctl_disable_cpumask_present)
+		return false;
+
+	/*
+	 * We operate on a cluster basis. Disable the core_ctl for
+	 * a cluster, if all of it's cpus are specified in
+	 * core_ctl_disable_cpumask
+	 */
+	return cpumask_subset(mask, core_ctl_disable_cpumask);
+}
+
 static struct cluster_data *find_cluster_by_first_cpu(unsigned int first_cpu)
 {
 	unsigned int i;
@@ -952,6 +991,9 @@ static int cluster_init(const struct cpumask *mask)
 	unsigned int cpu;
 	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 
+	if (should_skip(mask))
+		return 0;
+
 	if (find_cluster_by_first_cpu(first_cpu))
 		return 0;
 
@@ -1052,6 +1094,9 @@ static int __init core_ctl_init(void)
 {
 	unsigned int cpu;
 
+	if (should_skip(cpu_possible_mask))
+		return 0;
+
 	core_ctl_check_interval = (rq_avg_period_ms - RQ_AVG_TOLERANCE)
 					* NSEC_PER_MSEC;