Re: [PATCH v5 01/12] mm/sparse-vmemmap: factor out shared vmemmap tail page allocation

[David Hildenbrand (Arm)]

On 9/27/26 04:54, Muchun Song wrote:
> HugeTLB and sparse-vmemmap each have their own helper to allocate the
> shared vmemmap tail page used by vmemmap optimization.
> 
> Factor that logic into a common vmemmap_shared_tail_page() helper. It
> allocates the page through vmemmap_alloc_block(), initializes the tail
> struct pages, and uses cmpxchg() to install the per-zone shared page.
> 
> This removes duplicate allocation logic while handling both early boot
> and runtime allocation through the same helper.
> 
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> Acked-by: Qi Zheng <qi.zheng@xxxxxxxxx>
> Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> ---
> v5:
> - Move this patch before CONFIG_VMEMMAP_OPTIMIZATION is introduced
> 
> v4:
> - Update the commit message for the renamed VMEMMAP_OPTIMIZATION config
> - Collect Acked-by from Mike Rapoport
> 
> v2:
> - Collect Acked-by from Qi Zheng
> ---

[...]

>  
>  #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
> -static __meminit struct page *vmemmap_get_tail(unsigned int order, struct zone *zone)
> +struct page __ref *vmemmap_shared_tail_page(unsigned int order, struct zone *zone)
>  {
> -	struct page *p, *tail;
> -	unsigned int idx;
> -	int node = zone_to_nid(zone);
> +	void *addr;
> +	struct page *page;
> +	const unsigned int idx = order - VMEMMAP_OPTIMIZATION_MIN_ORDER;

Nit: constants read much nicer all the way at the top.


Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>

-- 
Cheers,

David