[PATCH v3 00/12] arm64: Add HOTPLUG_PARALLEL support for secondary CPUs

[Will Deacon]

On Wed, Jun 24, 2026 at 05:25:25PM +0800, Jinjie Ruan wrote:
> Support for parallel secondary CPU bringup is already utilized by x86,
> MIPS, and RISC-V. This patch brings this capability to the arm64
> architecture.
> 
> Introduce CONFIG_HOTPLUG_PARALLEL_SMT to avoid primary SMT threads
> to boot first constraint.
> 
> And add a 'cpu' parameter to update_cpu_boot_status() to allow updating
> the boot status at a per-CPU granularity during parallel bringup.
> 
> Rework the global `secondary_data` and `__early_cpu_boot_status` accessed
> during early boot into per-CPU arrays to allow secondary CPUs to boot
> in parallel.
> 
> And reuse `__cpu_logical_map` array in the early boot code in head.S
> to resolve each secondary CPU's logical ID concurrently.
> 
> This series includes a subset of the refactoring patches proposed
> by Will Deacon, with further adjustments.

Sheesh, Jinjie, what are you doing?

I said yesterday that I would dust off the old series after the merge
window:

  https://lore.kernel.org/all/ajqYaklhIyvaNLlk@willie-the-truck/

"Please just give me a week or so to rebase my changes and send them out
 for discussion"

but instead, you've posted patches from me that are missing a bunch of
fixes that need to be folded back in:

  https://web.git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=cpu-hotplug&id=2d5b8df5d4e2bbc142e3b4f21cabbca96e3da79d

so now you're asking people to review incomplete patches from somebody
else.

Please just give me the time I asked for. If you want to help out in the
meantime, there are plenty of patches that need reviewing...

Will