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Diffstat (limited to 'Documentation/cpu-hotplug.txt')
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 14 |
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 |