Re: [RFC PATCH] kernel/cpu: restart cpu_up when hotplug is disabled

[David Hildenbrand]

On 21.04.22 16:31, David Hildenbrand wrote:
>>> It's far from perfect I would say, but we really wanted to avoid
>>> letting user space having to deal with retry logic.
>>
>> What's so hard with retry logic in user space? 
>>
>> If you can come up with a reasonable argument why user space cannot be
>> fixed, then there is certainly a better solution than slapping a
>> msleep(5) at some random place into the code.
> Most probably you're right and we should just retry in udev. Staring at
> the history, it looks like the -EBUSY might have been returned forever,
> so user space just never really triggered it on actual CPU hotplug
> because it doesn't usually happen that cpu hotplug is disabled.

The last part was confusing: "on actual CPU hotplug because it doesn't
usually happen that cpu hotplug is disabled when onlining a CPU that was
just hotplugged."

-- 
Thanks,

David / dhildenb