From: Rik van Riel <r...@redhat.com>
Currently there is no way to query which CPUs are in nohz_full
mode from userspace.
Export the CPU list running in nohz_full mode in sysfs,
specifically in the file /sys/devices/system/cpu/nohz_full
Signed-off-by: Rik van Riel <r...@redhat.com>
---
drivers/base/cpu.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index ea23ee7b545b..78720e706176 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -16,6 +16,7 @@
#include <linux/acpi.h>
#include <linux/of.h>
#include <linux/cpufeature.h>
+#include <linux/tick.h>
#include "base.h"
@@ -276,6 +277,19 @@ static ssize_t print_cpus_isolated(struct device *dev,
}
static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
+#ifdef CONFIG_NO_HZ_FULL
+static ssize_t print_cpus_nohz_full(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int n = 0, len = PAGE_SIZE-2;
+
+ n = scnprintf(buf, len, "%*pbl\n",
cpumask_pr_args(tick_nohz_full_mask));
+
+ return n;
+}
+static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
+#endif
+
static void cpu_device_release(struct device *dev)
{
/*
@@ -443,6 +457,9 @@ static struct attribute *cpu_root_attrs[] = {
&dev_attr_kernel_max.attr,
&dev_attr_offline.attr,
&dev_attr_isolated.attr,
+#ifdef CONFIG_NO_HZ_FULL
+ &dev_attr_nohz_full.attr,
+#endif
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
&dev_attr_modalias.attr,
#endif
--
2.1.0
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