Re: [PATCH 08/10] mm/slub: Fix MAX_ORDER usage in calculate_order()

[Vlastimil Babka]

On 3/15/23 12:31, Kirill A. Shutemov wrote:
> MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> can deliver is MAX_ORDER-1.
> 
> Fix MAX_ORDER usage in calculate_order().
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Pekka Enberg <penberg@xxxxxxxxxx>

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  mm/slub.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 39327e98fce3..32eb6b50fe18 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4171,7 +4171,7 @@ static inline int calculate_order(unsigned int size)
>  	/*
>  	 * Doh this slab cannot be placed using slub_max_order.
>  	 */
> -	order = calc_slab_order(size, 1, MAX_ORDER, 1);
> +	order = calc_slab_order(size, 1, MAX_ORDER - 1, 1);
>  	if (order < MAX_ORDER)
>  		return order;
>  	return -ENOSYS;