korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-14 15:54:15 +08:00
Code Issues Packages Projects Releases Wiki Activity

[PATCH] x86_64: Don't reserve hotplug CPUs by default

Browse Source 
Most users don't need it so no need to waste memory.
This means an user has to specify the appropiate number of
hotplug CPUs on the command line with additional_cpus=...
or fix their BIOS to follow the convention in
Documentation/x86-64/cpu-hotplug-spec

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2006-01-11 22:42:35 +01:00 committed by Linus Torvalds
parent 92934bcbf9
commit f62a91f691
2 changed files with 5 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/x86_64/boot-options.txt
View File

@ -125,7 +125,7 @@ SMP
cpumask=MASK only use cpus with bits set in mask
additional_cpus=NUM Allow NUM more CPUs for hotplug
(defaults are specified by the BIOS or half the available CPUs)
(defaults are specified by the BIOS, see Documentation/x86_64/cpu-hotplug-spec)
NUMA

11
arch/x86_64/kernel/smpboot.c
View File

@ -927,8 +927,8 @@ int additional_cpus __initdata = -1;
*
* Three ways to find out the number of additional hotplug CPUs:
* - If the BIOS specified disabled CPUs in ACPI/mptables use that.
* - otherwise use half of the available CPUs or 2, whatever is more.
* - The user can overwrite it with additional_cpus=NUM
* - Otherwise don't reserve additional CPUs.
* We do this because additional CPUs waste a lot of memory.
* -AK
*/
@ -938,13 +938,10 @@ __init void prefill_possible_map(void)
int possible;
if (additional_cpus == -1) {
if (disabled_cpus > 0) {
if (disabled_cpus > 0)
additional_cpus = disabled_cpus;
} else {
additional_cpus = num_processors / 2;
if (additional_cpus == 0)
additional_cpus = 2;
}
else
additional_cpus = 0;
}
possible = num_processors + additional_cpus;
if (possible > NR_CPUS)