Re: [PATCH] mm, percpu: do not consider sleepable allocations atomic

[Vlastimil Babka]

On 3/5/25 16:10, Michal Hocko wrote:
> Sorry, I have missed follow ups here.
> 
>> I assume it's probably not easy to
>> implement as page table allocations are involved in the process and we don't
>> have a way to supply preallocated memory for those.
> 
> Why would this be a concern if the allocation is done outside of the
> lock?

It's not a concern if it can be done outside of the lock. I don't know the
code enough to see if it's feasible. There's e.g. pcpu_populate_chunk()
ending up doing vmap_pages_range_noflush() that AFAIK means page table
allocations. Can it be done outside of the lock?