path: root/Documentation/cpu-hotplug.txt
diff options
authorHeiko Carstens <heiko.carstens@de.ibm.com>2006-02-20 18:27:58 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-20 20:00:10 -0800
commit6303dbf570e410067380daec670fdb4137ac0d1d (patch)
tree19ae622f55fb1717a09617d1de8f0672e47ee6c1 /Documentation/cpu-hotplug.txt
parent2e2b42636614f3c152672b5da67947ccbcbe0d32 (diff)
[PATCH] cpu hotplug documentation fix
Looks like there was a merge conflict when patches 8f8b1138fc9f65e3591aac83a4ee394fef34ac1d and 255acee706b333b79f593dd366f16e1f107cccc3 were applied which wasn't properly resolved. Fix this and add some additional description. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation/cpu-hotplug.txt')
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index e71bc6cbbc5e..57a09f99ecb0 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -46,10 +46,12 @@ maxcpus=n Restrict boot time cpus to n. Say if you have 4 cpus, using
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 [x86_64, s390 only] use this to limit hotpluggable cpus.
- This option sets
+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, s390
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
should only rely on this to count the #of cpus, but *MUST* not rely on the
@@ -57,6 +59,9 @@ apicid values in those tables for disabled apics. In the event BIOS doesnt
mark such hot-pluggable cpus as disabled entries, one could use this
parameter "additional_cpus=x" to represent those cpus in the cpu_possible_map.
+s390 uses the number of cpus it detects at IPL time to also the number of bits
+in cpu_possible_map. If it is desired to add additional cpus at a later time
+the number should be specified using this option or the possible_cpus option.
possible_cpus=n [s390 only] use this to set hotpluggable cpus.
This option sets possible_cpus bits in

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