smp: Support random core control by bootargs

Add early_cpu_mask to remember user cpu want to remove.
hotplug and cpufreq driver uses it when control
number of online core.

Change-Id: I20977beb5e338a977f73db9a943d0ac2d3c52d93
Signed-off-by: Youngtae Lee <yt0729.lee@samsung.com>

diff --git a/drivers/cpufreq/exynos-acme.c b/drivers/cpufreq/exynos-acme.c
index 18d8adb99eafa69e3c2bab7a25d2db93716127ff..41d209af4abfca0f080545996403eef874303cfd 100644 (file)
--- a/drivers/cpufreq/exynos-acme.c
+++ b/drivers/cpufreq/exynos-acme.c
@@ -977,6 +977,7 @@ static ssize_t show_cpufreq_max_limit(struct kobject *kobj,
 }
 
 struct pm_qos_request cpu_online_max_qos_req;
+extern struct cpumask early_cpu_mask;
 static void enable_domain_cpus(struct exynos_cpufreq_domain *domain)
 {
        struct cpumask mask;
@@ -984,7 +985,7 @@ static void enable_domain_cpus(struct exynos_cpufreq_domain *domain)
        if (domain == first_domain())
                return;
 
-       cpumask_or(&mask, cpu_online_mask, &domain->cpus);
+       cpumask_or(&mask, &early_cpu_mask, &domain->cpus);
        pm_qos_update_request(&cpu_online_max_qos_req, cpumask_weight(&mask));
 }
 
@@ -995,7 +996,7 @@ static void disable_domain_cpus(struct exynos_cpufreq_domain *domain)
        if (domain == first_domain())
                return;
 
-       cpumask_andnot(&mask, cpu_online_mask, &domain->cpus);
+       cpumask_andnot(&mask, &early_cpu_mask, &domain->cpus);
        pm_qos_update_request(&cpu_online_max_qos_req, cpumask_weight(&mask));
 }
 

diff --git a/drivers/soc/samsung/exynos-cpu_hotplug.c b/drivers/soc/samsung/exynos-cpu_hotplug.c
index c4a2deb9754a259bcab7765f3c2cf21c755bba60..44457f504202a87e85b9de29b23e6a8b2fad087c 100644 (file)
--- a/drivers/soc/samsung/exynos-cpu_hotplug.c
+++ b/drivers/soc/samsung/exynos-cpu_hotplug.c
@@ -136,6 +136,7 @@ bool exynos_cpu_hotplug_enabled(void)
  * than maximum online CPU. If mininum is greater than maximum, online CPU will
  * be maximum.
  */
+extern struct cpumask early_cpu_mask;
 static struct cpumask create_cpumask(void)
 {
        int online_cpu_min, online_cpu_max;
@@ -147,11 +148,25 @@ static struct cpumask create_cpumask(void)
 
        cpumask_clear(&mask);
 
-       for (cpu = 0; cpu < online_cpu_min; cpu++)
-               cpumask_set_cpu(cpu, &mask);
+       for_each_possible_cpu (cpu) {
+               if (!cpumask_test_cpu(cpu, &early_cpu_mask))
+                       continue;
+
+               if (cpumask_weight(&mask) < online_cpu_min)
+                       cpumask_set_cpu(cpu, &mask);
+               else
+                       break;
+       }
 
-       for (cpu = nr_cpu_ids - 1; cpu >= online_cpu_max; cpu--)
-               cpumask_clear_cpu(cpu, &mask);
+       for (cpu = nr_cpu_ids - 1; cpu >= 0; cpu--) {
+               if (!cpumask_test_cpu(cpu, &early_cpu_mask))
+                       continue;
+
+               if (cpumask_weight(&mask) > online_cpu_max)
+                       cpumask_clear_cpu(cpu, &mask);
+               else
+                       break;
+       }
 
        return mask;
 }
@@ -263,6 +278,7 @@ static int control_cpu_hotplug(bool enable)
 
                cpumask_setall(&mask);
                cpumask_andnot(&mask, &mask, cpu_online_mask);
+               cpumask_and(&mask, &mask, &early_cpu_mask);
 
                /*
                 * If it success to enable all CPUs, clear cpu_hotplug.enabled flag.

diff --git a/kernel/smp.c b/kernel/smp.c
index c94dd85c8d41798443a7080af55c24fe508815b3..0f2aff5dc1a69e1e6f7e4c692466298476b3c3eb 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -499,6 +499,8 @@ EXPORT_SYMBOL(smp_call_function);
 /* Setup configured maximum number of CPUs to activate */
 unsigned int setup_max_cpus = NR_CPUS;
 EXPORT_SYMBOL(setup_max_cpus);
+struct cpumask early_cpu_mask;
+EXPORT_SYMBOL(early_cpu_mask);
 
 
 /*
@@ -570,12 +572,16 @@ void __init smp_init(void)
 
        pr_info("Bringing up secondary CPUs ...\n");
 
+       cpumask_clear(&early_cpu_mask);
+       cpumask_set_cpu(0, &early_cpu_mask);
        /* FIXME: This should be done in userspace --RR */
        for_each_present_cpu(cpu) {
                if (num_online_cpus() >= setup_max_cpus)
                        break;
-               if (!cpu_online(cpu))
+               if (!cpu_online(cpu)) {
                        cpu_up(cpu);
+                       cpumask_set_cpu(cpu, &early_cpu_mask);
+               }
        }
 
        num_nodes = num_online_nodes();