X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=Documentation%2Fcpu-hotplug.txt;h=9d620c153b04f2469bf664e6489e3af6817663e2;hp=fb94f5a71b688ae6fda63156a2b0bbdcf5387873;hb=9a1607071c293e48b08bd703733480b1d55c7b93;hpb=86ef5c9a8edd78e6bf92879f32329d89b2d55b5a diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index fb94f5a..9d620c1 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -50,24 +50,20 @@ 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 -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. -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. +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. - This option overrides additional_cpus. CPU maps and such -----------------