[PATCH] s390: additional_cpus parameter
Introduce additional_cpus command line option. By default no additional cpu
can be attached to the system anymore. Only the cpus present at IPL time can
be switched on/off. If it is desired that additional cpus can be attached to
the system the maximum number of additional cpus needs to be specified with
this option.
This change is necessary in order to limit the waste of per_cpu data
structures.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index e052780..4d3355d 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -11,6 +11,8 @@
Joel Schopp <jschopp@austin.ibm.com>
ia64/x86_64:
Ashok Raj <ashok.raj@intel.com>
+ s390:
+ Heiko Carstens <heiko.carstens@de.ibm.com>
Authors: Ashok Raj <ashok.raj@intel.com>
Lots of feedback: Nathan Lynch <nathanl@austin.ibm.com>,
@@ -44,11 +46,9 @@
maxcpus=2 will only boot 2. You can choose to bring the
other cpus later online, read FAQ's for more info.
-additional_cpus*=n Use this to limit hotpluggable cpus. This option sets
- cpu_possible_map = cpu_present_map + additional_cpus
-
-(*) Option valid only for following architectures
-- x86_64, ia64
+additional_cpus=n [x86_64, s390 only] use this to limit hotpluggable cpus.
+ This option sets
+ cpu_possible_map = cpu_present_map + additional_cpus
ia64 and x86_64 use the number of disabled local apics in ACPI tables MADT
to determine the number of potentially hot-pluggable cpus. The implementation