Re: [PATCH v4 6/6] mm: hugetlb: allocate frozen pages in alloc_gigantic_folio()

[Kefeng Wang <wangkefeng.wang@huawei.com>]

On 2025/12/17 2:44, Zi Yan wrote:
> On 16 Dec 2025, at 6:48, Kefeng Wang wrote:
> 
>> The alloc_gigantic_folio() allocates a folio with refcount increated
>> and then freeze it, convert to allocate a frozen folio to remove the
>> atomic operation about folio refcount, and saving atomic operation
>> during __update_and_free_hugetlb_folio() too.
>>
>> Besides, rename hugetlb_cma_{alloc,free}_folio() with frozen which
>> make them more self-explanatory.
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
>> ---
>>   mm/hugetlb.c     | 63 +++++++++++-------------------------------------
>>   mm/hugetlb_cma.c |  9 +++----
>>   mm/hugetlb_cma.h | 10 ++++----
>>   3 files changed, 22 insertions(+), 60 deletions(-)
>>
>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index ed185bbca419..7779ec838da0 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -121,16 +121,6 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
>>   		unsigned long start, unsigned long end, bool take_locks);
>>   static struct resv_map *vma_resv_map(struct vm_area_struct *vma);
>>
>> -static void hugetlb_free_folio(struct folio *folio)
>> -{
>> -	if (folio_test_hugetlb_cma(folio)) {
>> -		hugetlb_cma_free_folio(folio);
>> -		return;
>> -	}
>> -
>> -	folio_put(folio);
>> -}
>> -
>>   static inline bool subpool_is_free(struct hugepage_subpool *spool)
>>   {
>>   	if (spool->count)
>> @@ -1417,51 +1407,24 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h,
>>   	return NULL;
>>   }
>>
>> -#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
>> -#ifdef CONFIG_CONTIG_ALLOC
>> +#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && defined(CONFIG_CONTIG_ALLOC)
>>   static struct folio *alloc_gigantic_folio(int order, gfp_t gfp_mask,
>>   		int nid, nodemask_t *nodemask)
>>   {
>>   	struct folio *folio;
>> -	bool retried = false;
>>
>> -retry:
>> -	folio = hugetlb_cma_alloc_folio(order, gfp_mask, nid, nodemask);
>> -	if (!folio) {
>> -		struct page *page;
>> -
>> -		if (hugetlb_cma_exclusive_alloc())
>> -			return NULL;
>> -
>> -		page = alloc_contig_frozen_pages(1 << order, gfp_mask, nid, nodemask);
>> -		if (!page)
>> -			return NULL;
>> -
>> -		set_page_refcounted(page);
>> -		folio = page_folio(page);
>> -	}
>> -
>> -	if (folio_ref_freeze(folio, 1))
>> +	folio = hugetlb_cma_alloc_frozen_folio(order, gfp_mask, nid, nodemask);
>> +	if (folio)
>>   		return folio;
> 
> alloc_gigantic_folio() actually returns a frozen folio. Should it be renamed
> to alloc_frozen_gigantic_folio()?

I don't change it as alloc_buddy_hugetlb_folio is not with frozen, we 
could change both of them if you prefer with frozen :)
	

> 
> 
> Best Regards,
> Yan, Zi
>