Re: [PATCH-next 00/23] cgroup/cpuset: Enable runtime update of nohz_full and managed_irq CPUs

Le Thu, Jun 25, 2026 at 01:27:54AM -0400, Waiman Long a écrit :
> On 6/24/26 2:34 AM, Jing Wu wrote:
> >    3. Are there specific patches in your series where you would welcome
> >       our contribution directly?
> 
> I have broken down the shutdown callback into separate portions as suggested
> by Thomas. The other major change that I am working on is to try to shutdown
> to only CPUHP_AP_OFFLINE state instead of all the way down to CPUHP_OFFLINE.

What was the reason for that already? Can we perhaps ask the user to offline
the target CPUs before toggling isolation on them?

> That will require some adjustments to the nohz_full related hotplug
> functions. I have some ideas of what needs to be done. However, I haven't
> looked into RCU yet. I know RCU support changing the nocb mask for fully
> offline CPUs, I will need to find out if it possible to do that for
> partially offline CPUs.

No because callbacks can still be enqueued at this stage. But we could
manage to make it work with CPUHP_AP_IDLE_DEAD.

Thanks.

-- 
Frederic Weisbecker
SUSE Labs