diff options
| -rw-r--r-- | Documentation/x86_64/boot-options.txt | 2 | ||||
| -rw-r--r-- | arch/x86_64/kernel/smpboot.c | 11 |
2 files changed, 5 insertions, 8 deletions
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index e566affeed7f..72ab9b99b22c 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -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 diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c index ecbd7b83acc1..043b1d262a30 100644 --- a/arch/x86_64/kernel/smpboot.c +++ b/arch/x86_64/kernel/smpboot.c @@ -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) |