[CPUFREQ] expose cpufreq coordination requirements regardless of coordination mechanism

Currently, affected_cpus shows which CPUs need to have their frequency
coordinated in software.  When hardware coordination is in use, the contents
of this file appear the same as when no coordination is required.  This can
lead to some confusion among user-space programs, for example, that do not
know that extra coordination is required to force a CPU core to a particular
speed to control power consumption.

To fix this, create a "related_cpus" attribute that always displays the
coordination map regardless of whatever coordination strategy the cpufreq
driver uses (sw or hw).  If the cpufreq driver does not provide a value, fall
back to policy->cpus.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>

diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 8db8f73503b3cf8a82e9c550da8535aa0cade0d1..b0c8208df9fa17363b5a3ed5ce35bdec8c52ad25 100644 (file)
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -601,6 +601,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
            policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
                policy->cpus = perf->shared_cpu_map;
        }
+       policy->related_cpus = perf->shared_cpu_map;
 
 #ifdef CONFIG_SMP
        dmi_check_system(sw_any_bug_dmi_table);

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index d3575f5ec6d23be5dbd1fe76d275e1c10b56a9e1..7fce038fa57e6413892679f6c8ca7256aeedafa3 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -583,15 +583,13 @@ out:
        i += sprintf(&buf[i], "\n");
        return i;
 }
-/**
- * show_affected_cpus - show the CPUs affected by each transition
- */
-static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
+
+static ssize_t show_cpus(cpumask_t mask, char *buf)
 {
        ssize_t i = 0;
        unsigned int cpu;
 
-       for_each_cpu_mask(cpu, policy->cpus) {
+       for_each_cpu_mask(cpu, mask) {
                if (i)
                        i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
                i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
@@ -602,6 +600,25 @@ static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
        return i;
 }
 
+/**
+ * show_related_cpus - show the CPUs affected by each transition even if
+ * hw coordination is in use
+ */
+static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
+{
+       if (cpus_empty(policy->related_cpus))
+               return show_cpus(policy->cpus, buf);
+       return show_cpus(policy->related_cpus, buf);
+}
+
+/**
+ * show_affected_cpus - show the CPUs affected by each transition
+ */
+static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
+{
+       return show_cpus(policy->cpus, buf);
+}
+
 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
                                        const char *buf, size_t count)
 {
@@ -646,6 +663,7 @@ define_one_ro(cpuinfo_max_freq);
 define_one_ro(scaling_available_governors);
 define_one_ro(scaling_driver);
 define_one_ro(scaling_cur_freq);
+define_one_ro(related_cpus);
 define_one_ro(affected_cpus);
 define_one_rw(scaling_min_freq);
 define_one_rw(scaling_max_freq);
@@ -658,6 +676,7 @@ static struct attribute *default_attrs[] = {
        &scaling_min_freq.attr,
        &scaling_max_freq.attr,
        &affected_cpus.attr,
+       &related_cpus.attr,
        &scaling_governor.attr,
        &scaling_driver.attr,
        &scaling_available_governors.attr,

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index ddd8652fc3f38a91d5f471fd70a534e21337ba12..a881fd62c4479de56bdb1967578d497252443403 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -83,7 +83,8 @@ struct cpufreq_real_policy {
 };
 
 struct cpufreq_policy {
-       cpumask_t               cpus;   /* affected CPUs */
+       cpumask_t               cpus;   /* CPUs requiring sw coordination */
+       cpumask_t               related_cpus; /* CPUs with any coordination */
        unsigned int            shared_type; /* ANY or ALL affected CPUs
                                                should set cpufreq */
        unsigned int            cpu;    /* cpu nr of registered CPU */