path: root/Documentation/cpu-hotplug.txt
diff options
authorAshok Raj <ashok.raj@intel.com>2006-02-16 14:01:48 -0800
committerTony Luck <tony.luck@intel.com>2006-02-16 14:10:50 -0800
commit8f8b1138fc9f65e3591aac83a4ee394fef34ac1d (patch)
tree2c4d34391681cb5aa5ed8e5f2def1502a8a4b333 /Documentation/cpu-hotplug.txt
parent6f6d75825dc49b082906b84537b4df28293c2977 (diff)
[IA64] Count disabled cpus as potential hot-pluggable CPUs
Minor updates to earlier patch. - Added to documentation to add ia64 as well. - Minor clarification on how to use disabled cpus - used plain max instead of max_t per Andew Morton. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'Documentation/cpu-hotplug.txt')
1 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index 08c5d04f3086..e05278087ffa 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -44,10 +44,20 @@ 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 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
+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
+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.
CPU maps and such
[More on cpumaps and primitive to manipulate, please check

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