linux-kernel - Re: [PATCH v2 1/2] mm/hugetlb: create hstate_is_gigantic_no

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Message-ID: <2740dc95-d6a4-4eaf-9ac0-651cad13e13a@huawei.com>
Date: Mon, 13 Oct 2025 20:49:03 +0800
From: Kefeng Wang <wangkefeng.wang@...wei.com>
To: Usama Arif <usamaarif642@...il.com>, <muchun.song@...ux.dev>,
	<osalvador@...e.de>, <david@...hat.com>, Andrew Morton
	<akpm@...ux-foundation.org>
CC: <shakeel.butt@...ux.dev>, <linux-mm@...ck.org>, <hannes@...xchg.org>,
	<riel@...riel.com>, <kas@...nel.org>, <linux-kernel@...r.kernel.org>,
	<kernel-team@...a.com>
Subject: Re: [PATCH v2 1/2] mm/hugetlb: create hstate_is_gigantic_no_runtime
 helper



On 2025/10/10 1:24, Usama Arif wrote:
> This is a common condition used to skip operations that cannot
> be performed on gigantic pages when runtime support is disabled.
> This helper is introduced as the condition will exist even more
> when allowing "overcommit" of gigantic hugepages.
> No functional change intended with this patch.
> 
> Suggested-by: Andrew Morton <akpm@...ux-foundation.org>
> Signed-off-by: Usama Arif <usamaarif642@...il.com>

Reviewed-by: Kefeng Wang <wangkefeng.wang@...wei.com>

> ---
>   mm/hugetlb.c | 21 ++++++++++++++++-----
>   1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index c07b7192aff26..e74e41386b100 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -134,6 +134,17 @@ static void hugetlb_free_folio(struct folio *folio)
>   	folio_put(folio);
>   }
>   
> +/*
> + * Check if the hstate represents gigantic pages but gigantic page
> + * runtime support is not available. This is a common condition used to
> + * skip operations that cannot be performed on gigantic pages when runtime
> + * support is disabled.
> + */
> +static inline bool hstate_is_gigantic_no_runtime(struct hstate *h)
> +{
> +	return hstate_is_gigantic(h) && !gigantic_page_runtime_supported();
> +}
> +
>   static inline bool subpool_is_free(struct hugepage_subpool *spool)
>   {
>   	if (spool->count)
> @@ -1555,7 +1566,7 @@ static void remove_hugetlb_folio(struct hstate *h, struct folio *folio,
>   	VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio_rsvd(folio), folio);
>   
>   	lockdep_assert_held(&hugetlb_lock);
> -	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
> +	if (hstate_is_gigantic_no_runtime(h))
>   		return;
>   
>   	list_del(&folio->lru);
> @@ -1617,7 +1628,7 @@ static void __update_and_free_hugetlb_folio(struct hstate *h,
>   {
>   	bool clear_flag = folio_test_hugetlb_vmemmap_optimized(folio);
>   
> -	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
> +	if (hstate_is_gigantic_no_runtime(h))
>   		return;
>   
>   	/*
> @@ -2511,7 +2522,7 @@ static void return_unused_surplus_pages(struct hstate *h,
>   	/* Uncommit the reservation */
>   	h->resv_huge_pages -= unused_resv_pages;
>   
> -	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
> +	if (hstate_is_gigantic_no_runtime(h))
>   		goto out;
>   
>   	/*
> @@ -3725,7 +3736,7 @@ static void __init hugetlb_init_hstates(void)
>   		 * - If CMA allocation is possible, we can not demote
>   		 *   HUGETLB_PAGE_ORDER or smaller size pages.
>   		 */
> -		if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
> +		if (hstate_is_gigantic_no_runtime(h))
>   			continue;
>   		if (hugetlb_cma_total_size() && h->order <= HUGETLB_PAGE_ORDER)
>   			continue;
> @@ -4202,7 +4213,7 @@ static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
>   	int err;
>   	nodemask_t nodes_allowed, *n_mask;
>   
> -	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
> +	if (hstate_is_gigantic_no_runtime(h))
>   		return -EINVAL;
>   
>   	if (nid == NUMA_NO_NODE) {