Re: [PATCH v5 1/6] mm: debug_vm_pgtable: add debug_vm_pgtable_free_huge_page()

[Sid Kumar <sidhartha.kumar@oracle.com>]

On 12/30/25 1:24 AM, Kefeng Wang wrote:
> Add a new helper to free huge page to be consistency to
> debug_vm_pgtable_alloc_huge_page(), and use HPAGE_PUD_ORDER
> instead of open-code.
>
> Also move the free_contig_range() under CONFIG_ALLOC_CONTIG
> since all caller are built with CONFIG_ALLOC_CONTIG.
>
> Acked-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Muchun Song <muchun.song@linux.dev>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   include/linux/gfp.h   |  2 +-
>   mm/debug_vm_pgtable.c | 38 +++++++++++++++++---------------------
>   mm/page_alloc.c       |  2 +-
>   3 files changed, 19 insertions(+), 23 deletions(-)

Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>

> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index b155929af5b1..ea053f1cfa16 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -438,8 +438,8 @@ extern struct page *alloc_contig_pages_noprof(unsigned long nr_pages, gfp_t gfp_
>   					      int nid, nodemask_t *nodemask);
>   #define alloc_contig_pages(...)			alloc_hooks(alloc_contig_pages_noprof(__VA_ARGS__))
>   
> -#endif
>   void free_contig_range(unsigned long pfn, unsigned long nr_pages);
> +#endif
>   
>   #ifdef CONFIG_CONTIG_ALLOC
>   static inline struct folio *folio_alloc_gigantic_noprof(int order, gfp_t gfp,
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index ae9b9310d96f..83cf07269f13 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -971,22 +971,26 @@ static unsigned long __init get_random_vaddr(void)
>   	return random_vaddr;
>   }
>   
> -static void __init destroy_args(struct pgtable_debug_args *args)
> +static void __init
> +debug_vm_pgtable_free_huge_page(struct pgtable_debug_args *args,
> +		unsigned long pfn, int order)
>   {
> -	struct page *page = NULL;
> +#ifdef CONFIG_CONTIG_ALLOC
> +	if (args->is_contiguous_page) {
> +		free_contig_range(pfn, 1 << order);
> +		return;
> +	}
> +#endif
> +	__free_pages(pfn_to_page(pfn), order);
> +}
>   
> +static void __init destroy_args(struct pgtable_debug_args *args)
> +{
>   	/* Free (huge) page */
>   	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>   	    has_transparent_pud_hugepage() &&
>   	    args->pud_pfn != ULONG_MAX) {
> -		if (args->is_contiguous_page) {
> -			free_contig_range(args->pud_pfn,
> -					  (1 << (HPAGE_PUD_SHIFT - PAGE_SHIFT)));
> -		} else {
> -			page = pfn_to_page(args->pud_pfn);
> -			__free_pages(page, HPAGE_PUD_SHIFT - PAGE_SHIFT);
> -		}
> -
> +		debug_vm_pgtable_free_huge_page(args, args->pud_pfn, HPAGE_PUD_ORDER);
>   		args->pud_pfn = ULONG_MAX;
>   		args->pmd_pfn = ULONG_MAX;
>   		args->pte_pfn = ULONG_MAX;
> @@ -995,20 +999,13 @@ static void __init destroy_args(struct pgtable_debug_args *args)
>   	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>   	    has_transparent_hugepage() &&
>   	    args->pmd_pfn != ULONG_MAX) {
> -		if (args->is_contiguous_page) {
> -			free_contig_range(args->pmd_pfn, (1 << HPAGE_PMD_ORDER));
> -		} else {
> -			page = pfn_to_page(args->pmd_pfn);
> -			__free_pages(page, HPAGE_PMD_ORDER);
> -		}
> -
> +		debug_vm_pgtable_free_huge_page(args, args->pmd_pfn, HPAGE_PMD_ORDER);
>   		args->pmd_pfn = ULONG_MAX;
>   		args->pte_pfn = ULONG_MAX;
>   	}
>   
>   	if (args->pte_pfn != ULONG_MAX) {
> -		page = pfn_to_page(args->pte_pfn);
> -		__free_page(page);
> +		__free_page(pfn_to_page(args->pte_pfn));
>   
>   		args->pte_pfn = ULONG_MAX;
>   	}
> @@ -1242,8 +1239,7 @@ static int __init init_args(struct pgtable_debug_args *args)
>   	 */
>   	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
>   	    has_transparent_pud_hugepage()) {
> -		page = debug_vm_pgtable_alloc_huge_page(args,
> -				HPAGE_PUD_SHIFT - PAGE_SHIFT);
> +		page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PUD_ORDER);
>   		if (page) {
>   			args->pud_pfn = page_to_pfn(page);
>   			args->pmd_pfn = args->pud_pfn;
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index a045d728ae0f..206397ed33a7 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7248,7 +7248,6 @@ struct page *alloc_contig_pages_noprof(unsigned long nr_pages, gfp_t gfp_mask,
>   	}
>   	return NULL;
>   }
> -#endif /* CONFIG_CONTIG_ALLOC */
>   
>   void free_contig_range(unsigned long pfn, unsigned long nr_pages)
>   {
> @@ -7275,6 +7274,7 @@ void free_contig_range(unsigned long pfn, unsigned long nr_pages)
>   	WARN(count != 0, "%lu pages are still in use!\n", count);
>   }
>   EXPORT_SYMBOL(free_contig_range);
> +#endif /* CONFIG_CONTIG_ALLOC */
>   
>   /*
>    * Effectively disable pcplists for the zone by setting the high limit to 0