Re: [PATCH v1 3/5] mm/memory_hotplug: check if sections are already online/offline

[Pasha Tatashin]

On 8/16/18 7:00 AM, David Hildenbrand wrote:
> On 16.08.2018 12:47, Oscar Salvador wrote:
>> On Thu, Aug 16, 2018 at 12:06:26PM +0200, David Hildenbrand wrote:
>>
>>> +
>>> +/* check if all mem sections are offline */
>>> +bool mem_sections_offline(unsigned long pfn, unsigned long end_pfn)
>>> +{
>>> +	for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
>>> +		unsigned long section_nr = pfn_to_section_nr(pfn);
>>> +
>>> +		if (WARN_ON(!valid_section_nr(section_nr)))
>>> +			continue;
>>> +		if (online_section_nr(section_nr))
>>> +			return false;
>>> +	}
>>> +	return true;
>>> +}
>>
>> AFAICS pages_correctly_probed will catch this first.
>> pages_correctly_probed checks for the section to be:
>>
>> - present
>> - valid
>> - !online
> 
> Right, I missed that function.
> 
>>
>> Maybe it makes sense to rename it, and write another pages_correctly_probed routine
>> for the offline case.
>>
>> So all checks would stay in memory_block_action level, and we would not need
>> the mem_sections_offline/online stuff.

I am OK with that, but will wait for a patch to review.

Pavel