Re: [PATCH v4 1/4] driver/base: Optimize memory block registration to reduce boot time

[David Hildenbrand <david@redhat.com>]

>> We'd have to be smart about memory blocks that fall into multiple regions,
>> but it should be a corner case and doable.
> 
> This is a corner case that should be handled regardless of the loop order.
> And I don't think it's handled today at all.
> 
> If we have a block that crosses node boundaries, current implementation of
> register_mem_block_under_node_early() will register it under the first
> node.

At least upstream behavior should be that it would be linked under all 
nodes. At least that's what I remember :)

>   
>> OTOH, we usually don't expect having a lot of regions, so iterating over
>> them is probably not a big bottleneck? Anyhow, just wanted to raise it.
> 
> There would be at least a region per node and having
> 
> for_each_online_node()
> 	for_each_mem_region()
> 
> makes the loop O(n²) for no good reason.

Yes, that's why I mentioned it. If we have many nodes it might 
definitely be relevant.

-- 
Cheers,

David / dhildenb