Kernel uses the possible_cpus in command line to reset the possible_cpus bits in cpu_possible_map. It doesn't be recorded in the kernel-parameters.txt Add its description in this document, also replace the wrong option additional_cpus with possible_cpus in cpu-gotplug-spec. Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx> --- Documentation/admin-guide/kernel-parameters.txt | 5 +++++ Documentation/x86/x86_64/cpu-hotplug-spec | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1d1d53f85ddd..34f8a5f04e63 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2832,6 +2832,11 @@ variables need be pre-allocated for later physical cpu hot plugging. + possible_cpus= [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. + nr_uarts= [SERIAL] maximum number of UARTs to be registered. numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing. diff --git a/Documentation/x86/x86_64/cpu-hotplug-spec b/Documentation/x86/x86_64/cpu-hotplug-spec index 3c23e0587db3..d218bc0bdaaa 100644 --- a/Documentation/x86/x86_64/cpu-hotplug-spec +++ b/Documentation/x86/x86_64/cpu-hotplug-spec @@ -16,6 +16,6 @@ it should have its LAPIC Enabled bit set to 0. Linux will use the number of disabled LAPICs to compute the maximum number of future CPUs. In the worst case the user can overwrite this choice using a command line -option (additional_cpus=...), but it is recommended to supply the correct +option (possible_cpus=...), but it is recommended to supply the correct number (or a reasonable approximation of it, with erring towards more not less) in the MADT to avoid manual configuration. -- 2.14.3 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
