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Commit 6303dbf5 authored by Heiko Carstens's avatar Heiko Carstens Committed by Linus Torvalds
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[PATCH] cpu hotplug documentation fix 



Looks like there was a merge conflict when patches
8f8b1138 and
255acee7 were applied which wasn't properly
resolved. Fix this and add some additional description.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 2e2b4263

Documentation/cpu-hotplug.txt

+7 −2
Original line number Original line Diff line number Diff line
@@ -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

             maxcpus=2 will only boot 2. You can choose to bring the

             other cpus later online, read FAQ's for more info.

             other cpus later online, read FAQ's for more info.





additional_cpus=n	[x86_64, s390 only] use this to limit hotpluggable cpus.

additional_cpus*=n	Use this to limit hotpluggable cpus. This option sets

                          This option sets

  			cpu_possible_map = cpu_present_map + additional_cpus

  			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

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

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

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

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.

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 only] use this to set hotpluggable cpus.

			This option sets possible_cpus bits in

			This option sets possible_cpus bits in