diff options
Diffstat (limited to 'Documentation/cpu-hotplug.txt')
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index e71bc6cbbc5e..57a09f99ecb0 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -46,10 +46,12 @@ 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, s390 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, s390 + 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 @@ -57,6 +59,9 @@ 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. +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. This option sets possible_cpus bits in |