Re: [PATCH RFC v3 05/21] ACPI: Rename ACPI_HOTPLUG_CPU to include 'present'

"Rafael J. Wysocki" <[email protected]> Mon, 18 Dec 2023 21:35:16 +0100

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Message-ID	<CAJZ5v0g9nfLrEf9u4Ksw6BOWJQ9iv8Z-O8RsLU6jR5zk0ahxRw@mail.gmail.com>

On Wed, Dec 13, 2023 at 1:49 PM Russell King <[email protected]> wrote:
>
> From: James Morse <[email protected]>
>
> The code behind ACPI_HOTPLUG_CPU allows a not-present CPU to become
> present.

Right.

> This isn't the only use of HOTPLUG_CPU. On arm64 and riscv
> CPUs can be taken offline as a power saving measure.

But still there is the case in which a non-present CPU can become
present, isn't it there?

> On arm64 an offline CPU may be disabled by firmware, preventing it from
> being brought back online, but it remains present throughout.
>
> Adding code to prevent user-space trying to online these disabled CPUs
> needs some additional terminology.
>
> Rename the Kconfig symbol CONFIG_ACPI_HOTPLUG_PRESENT_CPU to reflect
> that it makes possible CPUs present.

Honestly, I don't think that this change is necessary or even useful.