On Thu, 5 Nov 2026 19:46:13 +0100 Daniel Lezcano [off-list ref] wrote:
On 11/3/26 00:09, Daniel Lezcano wrote:
quoted
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 ?
I'd volunteer Rafael's, after peterz/tglx review.
Please! Removing one kernel thread per cpu makes the world a better
place.