From 3b11ce7f542e415c90267b4482d4611410b468e6 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Wed, 17 Dec 2008 15:21:39 -0800 Subject: x86: use possible_cpus=NUM to extend the possible cpus allowed Impact: add new boot parameter Use possible_cpus=NUM kernel parameter to extend the number of possible cpus. The ability to HOTPLUG ON cpus that are "possible" but not "present" is dealt with in a later patch. Signed-off-by: Mike Travis --- Documentation/cpu-hotplug.txt | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'Documentation/cpu-hotplug.txt') diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 94bbc27ddd4..9d620c153b0 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -50,16 +50,17 @@ 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 -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 doesn't -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. +ia64 uses 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 doesn't 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. -possible_cpus=n [s390 only] use this to set hotpluggable cpus. +possible_cpus=n [s390,x86_64] use this to set hotpluggable cpus. This option sets possible_cpus bits in cpu_possible_map. Thus keeping the numbers of bits set constant even if the machine gets rebooted. -- cgit v1.2.3