[RFC PATCH v1 06/10] mm/hugetlb: use separate folio->_hugetlb_list for hugetlb-internals

[David Hildenbrand]

On 12.11.24 16:28, wang wei wrote:
> Signed-off-by: wang wei <a929244872 at 163.com>
> ---
>> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
>> index 80fef38d9d64..365c73be0bb4 100644
>> --- a/include/linux/mm_types.h
>> +++ b/include/linux/mm_types.h
>> @@ -310,6 +310,7 @@ typedef struct {
>>   * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
>>   * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
>>   * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
>> + * @_hugetlb_list: To be used in hugetlb core code only.
>>   * @_deferred_list: Folios to be split under memory pressure.
>>   * @_unused_slab_obj_exts: Placeholder to match obj_exts in struct slab.
>>   *
>> @@ -397,6 +398,17 @@ struct folio {
>> 		};
>> 		struct page __page_2;
>> 	};
>> +	union {
>> +		struct {
>> +			unsigned long _flags_3;
>> +			unsigned long _head_3;
>> +	/* public: */
>> +			struct list_head _hugetlb_list;
>> +	/* private: the union with struct page is transitional */
>> +		};
>> +		struct page __page_3;
>> +	};
>> +
>> };
>>
> As far as I know, increasing the size of folio maybe decrease
> the revenue of HVO, do you measure it?

We should always have a writable page2, even with HVO. So nothing should 
change at this point. Thanks!

-- 
Cheers,

David / dhildenb