xen/pcpu: Xen physical cpus online/offline sys interface
This patch provide Xen physical cpus online/offline sys interface.
User can use it for their own purpose, like power saving:
by offlining some cpus when light workload it save power greatly.
Its basic workflow is, user online/offline cpu via sys interface,
then hypercall xen to implement, after done xen inject virq back to dom0,
and then dom0 sync cpu status.
Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com>
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/Documentation/ABI/testing/sysfs-devices-system-xen_cpu b/Documentation/ABI/testing/sysfs-devices-system-xen_cpu
new file mode 100644
index 0000000..9ca02fb
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+What: /sys/devices/system/xen_cpu/
+Date: May 2012
+Contact: Liu, Jinsong <jinsong.liu@intel.com>
+Description:
+ A collection of global/individual Xen physical cpu attributes
+
+ Individual physical cpu attributes are contained in
+ subdirectories named by the Xen's logical cpu number, e.g.:
+ /sys/devices/system/xen_cpu/xen_cpu#/
+
+
+What: /sys/devices/system/xen_cpu/xen_cpu#/online
+Date: May 2012
+Contact: Liu, Jinsong <jinsong.liu@intel.com>
+Description:
+ Interface to online/offline Xen physical cpus
+
+ When running under Xen platform, it provide user interface
+ to online/offline physical cpus, except cpu0 due to several
+ logic restrictions and assumptions.