Re: [PATCH v3 2/2] mm/damon: introduce DAMOS filter type hugepage

[David Hildenbrand <david@redhat.com>]

On 20.01.25 20:58, Usama Arif wrote:
> 
> 
> On 20/01/2025 19:30, SeongJae Park wrote:
>> On Mon, 20 Jan 2025 20:23:20 +0100 David Hildenbrand <david@redhat.com> wrote:
>>
>>> On 20.01.25 20:16, SeongJae Park wrote:
>>>> On Mon, 20 Jan 2025 19:57:10 +0100 David Hildenbrand <david@redhat.com> wrote:
>>>>
>>>>> On 20.01.25 19:19, Usama Arif wrote:
>> [...]
>>>>>> +#if defined(CONFIG_PGTABLE_HAS_HUGE_LEAVES)
>>>>>> +	case DAMOS_FILTER_TYPE_HUGEPAGE:
>>>>>> +		matched = folio_size(folio) == HPAGE_PMD_SIZE;
>>>>>
>>>>>
>>>>> Can we directly embed in the name and the comments/docs that we are only
>>>>> talking about PMD size (both, THP and hugetlb)?
>>>>>
>>>>> DAMOS_FILTER_TYPE_PMD_HUGEPAGE or sth. like that.
>>>>
>>>> Nice suggestion, thank you!  And we might later add more filter types for
>>>> different size huge pages.  What about extending this to handle more general
>>>> case, though?  That is, we can let the filter receives a range of the folio
>>>> size to match, like DAMOS_FILTER_TYPE_ADDR does.  Then, the filter could be
>>>> used for any size of interest.
>>>
>>> That would probably be future proof: either a range or explicitly
>>> specified sizes (ranges?).
>>
>> DAMON supports installing multiple DAMOS filters.  So multiple DAMOS filters
>> that each matching single range can be used for the multiple sizes or ranges
>> use case.
>>
>>
> 
> Does creating something like schemes/<N>/access_pattern/page_size/{min,max}
> sound good? with the default value being pmd size?

"page_size" might be misleading. Not sure if we want to use the word 
"folio_size" here, so far it's more an internal detail that evolved from 
compound pages.

"hugepage_size" would at least match /sys/kernel/mm/hugepages/ and 
/sys/kernel/mm/transparent_hugepage/.

But if you would also support "single page" == e.g., 4K, "hugepage" 
would be wrong.

-- 
Cheers,

David / dhildenb