Re: [PATCH 6/6] mm/hugetlb: remove unnecessary empty range check in hugetlb_bootmem_set_nodes()

["David Hildenbrand (Arm)" <david@kernel.org>]

On 6/21/26 16:59, Sang-Heon Jeon wrote:
> hugetlb_bootmem_set_nodes() iterates the memory ranges with
> for_each_mem_pfn_range() and calls node_set(nid, hugetlb_bootmem_nodes)
> only when end_pfn > start_pfn. for_each_mem_pfn_range() never returns an
> empty range, so start_pfn < end_pfn always.
> 
> Therefore the check is unnecessary, so remove it.
> 
> No functional change.
> 
> Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
> ---
>  mm/hugetlb.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 571212b80835..d4d4c9df5f51 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -4450,8 +4450,7 @@ void __init hugetlb_bootmem_set_nodes(void)
>  		return;
>  
>  	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
> -		if (end_pfn > start_pfn)
> -			node_set(nid, hugetlb_bootmem_nodes);
> +		node_set(nid, hugetlb_bootmem_nodes);
>  	}
>  }

We have

	if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size))
		continue;

...

*out_start_pfn = PFN_UP(r->base);
*out_end_pfn = PFN_DOWN(r->base + r->size);

So we should always have *out_start_pfn < *out_end_pfn

Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David