Re: [PATCH RFC v3 21/21] cpumask: Add enabled cpumask for present CPUs that can be brought online

Thomas Gleixner <[email protected]> Fri, 15 Dec 2023 20:40:28 +0100
Newsgroups gmane.linux.ports.ia64,gmane.linux.power-management.general,gmane.linux.acpi.devel,gmane.linux.kernel.cross-arch,gmane.linux.kernel,gmane.linux.ports.arm.kernel,gmane.linux.ports.riscv,gmane.linux.documentation,gmane.linux.ports.parisc
Message-ID <87le9vmez7.ffs@tglx>
On Wed, Dec 13 2023 at 12:50, Russell King (Oracle) wrote:
> From: James Morse <[email protected]>
>
> The 'offline' file in sysfs shows all offline CPUs, including those
> that aren't present. User-space is expected to remove not-present CPUs
> from this list to learn which CPUs could be brought online.
>
> CPUs can be present but not-enabled. These CPUs can't be brought online
> until the firmware policy changes, which comes with an ACPI notification
> that will register the CPUs.
>
> With only the offline and present files, user-space is unable to
> determine which CPUs it can try to bring online. Add a new CPU mask
> that shows this based on all the registered CPUs.
>
> Signed-off-by: James Morse <[email protected]>
> Tested-by: Miguel Luis <[email protected]>
> Tested-by: Vishnu Pajjuri <[email protected]>
> Tested-by: Jianyong Wu <[email protected]>

Acked-by: Thomas Gleixner <[email protected]>