# Re: \[PATCH 0/2\] powercap: idle\_inject: Create threads on demand

- From: Daniel Lezcano \<hidden\>
- Date: 2026-11-05 18:46:47 
- List: linux-arm-kernel
- Page: https://ratatoskr.run/linux-arm-kernel/2026/11/17873159
- Thread: https://ratatoskr.run/linux-arm-kernel/2026/11/17848344/t.md

```text
On 11/3/26 00:09, Daniel Lezcano wrote:
> Idle injection currently registers per-CPU kernel threads during early
> initialization, including on CPUs for which no idle injection device
> will be registered.
>
> This series makes thread creation follow the lifetime and CPU mask of
> each idle injection device.
>
> The first patch adds an optional CPU mask to smpboot thread descriptors.
> The mask restricts thread creation, CPU hotplug handling and teardown,
> while preserving the existing behavior for descriptors without a mask.
>
> The second patch uses this support to register idle injection threads
> when a device registers and destroy them when it unregisters. CPU
> ownership claims, registration rollback and thread teardown are
> serialized to prevent overlapping registrations from sharing threads.
>
> Validation includes W=1 builds of the affected objects, whitespace
> checks and static review of the teardown locking paths. Concurrent
> registration and CPU hotplug runtime testing remains outstanding.
>
> The series was tested on Rockchip RK3588.

One thing not specified in this cover is which tree these changes have to go through ?
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Rafael J. Wysocki <rafael@kernel.org>
>
> Daniel Lezcano (2):
>    smpboot: Allow restricting per-CPU threads to a CPU mask
>    powercap: idle_inject: Create per-CPU threads on registration
>
>   drivers/powercap/idle_inject.c | 69 +++++++++++++++++++++-------------
>   include/linux/smpboot.h        |  4 ++
>   kernel/smpboot.c               | 17 ++++++++-
>   3 files changed, 61 insertions(+), 29 deletions(-)
>
>
> base-commit: c03c1a14507dfaf8b856c2608f9ac216021fc222


```