Re: [PATCH] docs: Update nosmt support for arm64

From: Jinjie Ruan

Date: Mon May 11 2026 - 02:18:16 EST


Gentle ping.

On 4/17/2026 11:25 AM, Jinjie Ruan wrote:
> commit eed4583bcf9a6 ("arm64: Kconfig: Enable HOTPLUG_SMT") enable
> HOTPLUG_SMT for SMT control for arm64, but the documentation was
> not updated accordingly to reflect that ARM64 now supports control SMT
> via boot parameter and sysfs knobs:
>
> 1. Boot parameters:
>
> nosmt: Disable SMT, can be enabled via sysfs knobs.
> nosmt=force: Disable SMT, cannot be enabled via sysfs knobs.
>
> 2. Runtime sysfs controls:
>
> Write "on", "off", "forceoff" or the number of SMT threads (1, 2, ...)
> to /sys/devices/system/cpu/smt/control.
>
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index cb850e5290c2..6a73eb5abae9 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4661,7 +4661,7 @@ Kernel parameters
> nosmt [KNL,MIPS,PPC,EARLY] Disable symmetric multithreading (SMT).
> Equivalent to smt=1.
>
> - [KNL,LOONGARCH,X86,PPC,S390] Disable symmetric multithreading (SMT).
> + [KNL,LOONGARCH,X86,ARM64,PPC,S390] Disable symmetric multithreading (SMT).
> nosmt=force: Force disable SMT, cannot be undone
> via the sysfs control file.
>