Re: [PATCH] mm: don't rely on system state to detect hot-plug operations

From: David Hildenbrand
Date: Wed Sep 09 2020 - 05:24:41 EST

>> I am not sure an enum is going to make the existing situation less
>> messy. Sure we somehow have to distinguish boot init and runtime hotplug
>> because they have different constrains. I am arguing that a) we should
>> have a consistent way to check for those and b) we shouldn't blow up
>> easily just because sysfs infrastructure has failed to initialize.
> For the point a, using the enum allows to know in register_mem_sect_under_node()
> if the link operation is due to a hotplug operation or done at boot time.
> For the point b, one option would be ignore the link error in the case the link
> is already existing, but that BUG_ON() had the benefit to highlight the root issue.

WARN_ON_ONCE() would be preferred - not crash the system but still
highlight the issue.

> Cheers,
> Laurent.


David / dhildenb