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 org.kernel.vger.linux-ia64,dev.linux.lists.acpica-devel,dev.linux.lists.kvmarm,dev.linux.lists.loongarch,org.infradead.lists.linux-arm-kernel,org.infradead.lists.linux-riscv,org.kernel.vger.linux-acpi,org.kernel.vger.linux-arch,org.kernel.vger.linux-csky,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-parisc,org.kernel.vger.linux-pm
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]>