Re: [PATCH v1] drivers/base/node.c: Simplify unregister_memory_block_under_nodes()

[David Hildenbrand]

On 19.07.19 13:36, Michal Hocko wrote:
> On Fri 19-07-19 11:20:43, David Hildenbrand wrote:
>> On 19.07.19 11:13, Michal Hocko wrote:
>>> On Fri 19-07-19 11:05:51, David Hildenbrand wrote:
>>>> On 19.07.19 10:42, Michal Hocko wrote:
>>>>> On Thu 18-07-19 16:22:39, David Hildenbrand wrote:
>>>>>> We don't allow to offline memory block devices that belong to multiple
>>>>>> numa nodes. Therefore, such devices can never get removed. It is
>>>>>> sufficient to process a single node when removing the memory block.
>>>>>>
>>>>>> Remember for each memory block if it belongs to no, a single, or mixed
>>>>>> nodes, so we can use that information to skip unregistering or print a
>>>>>> warning (essentially a safety net to catch BUGs).
>>>>>
>>>>> I do not really like NUMA_NO_NODE - 1 thing. This is yet another invalid
>>>>> node that is magic. Why should we even care? In other words why is this
>>>>> patch an improvement?
>>>>
>>>> Oh, and to answer that part of the question:
>>>>
>>>> We no longer have to iterate over each pfn of a memory block to be removed.
>>>
>>> Is it possible that we are overzealous when unregistering syfs files and
>>> we should simply skip the pfn walk even without this change?
>>>
>>
>> I assume you mean something like v1 without the warning/"NUMA_NO_NODE -1"?
>>
>> See what I have right now below.
> 
> Yes. I didn'g get to look closely but you caught the idea. Thanks!
> 

Will do a quick test and resent later this day, thanks for having a look!

-- 

Thanks,

David / dhildenb