diff options
| author | Mike Travis <travis@sgi.com> | 2008-12-17 15:21:39 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-12-18 12:08:05 +0100 |
| commit | 3b11ce7f542e415c90267b4482d4611410b468e6 (patch) | |
| tree | 26366b9f25af830b71c78504bbadd94896a8b82a /Documentation/cpu-hotplug.txt | |
| parent | a775a38b1353161a6d7af86b667d6523c12c1a37 (diff) | |
| download | lwn-3b11ce7f542e415c90267b4482d4611410b468e6.tar.gz lwn-3b11ce7f542e415c90267b4482d4611410b468e6.zip | |
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 <travis@sgi.com>
Diffstat (limited to 'Documentation/cpu-hotplug.txt')
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 94bbc27ddd4f..9d620c153b04 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. |