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authorRik van Riel <riel@redhat.com>2015-04-24 15:24:27 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-05-20 00:15:06 -0700
commit59f30abe94bff50636c8cad45207a01fdcb2ee49 (patch)
treede7d08069d48a1a0e7284530de7be26539c1dcdd
parente26081808edadfd257c6c9d81014e3b25e9a6118 (diff)
downloadlinux-59f30abe94bff50636c8cad45207a01fdcb2ee49.tar.bz2
show isolated cpus in sysfs
After system bootup, there is no totally reliable way to see which CPUs are isolated, because the kernel may modify the CPUs specified on the isolcpus= kernel command line option. Export the CPU list that actually got isolated in sysfs, specifically in the file /sys/devices/system/cpu/isolated This can be used by system management tools like libvirt, openstack, and others to ensure proper placement of tasks. Suggested-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com> Acked-by: Chris Metcalf <cmetcalf@ezchip.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/base/cpu.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index f160ea44a86d..ea23ee7b545b 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -265,6 +265,17 @@ static ssize_t print_cpus_offline(struct device *dev,
}
static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
+static ssize_t print_cpus_isolated(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(cpu_isolated_map));
+
+ return n;
+}
+static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
+
static void cpu_device_release(struct device *dev)
{
/*
@@ -431,6 +442,7 @@ static struct attribute *cpu_root_attrs[] = {
&cpu_attrs[2].attr.attr,
&dev_attr_kernel_max.attr,
&dev_attr_offline.attr,
+ &dev_attr_isolated.attr,
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
&dev_attr_modalias.attr,
#endif