On 9/20/23 09:44, Feng Tang wrote:
> Currently there are 2 parameters could be setup from kernel cmdline:
> slub_min_order and slub_max_order. It's possible that the user
> configured slub_min_order is bigger than the default slub_max_order
> [1], which can still take effect, as calculate_oder() will use MAX_ORDER
> as a fallback to check against, but has some downsides:
>
> * the kernel message about SLUB will be strange in showing min/max
> orders:
>
> SLUB: HWalign=64, Order=9-3, MinObjects=0, CPUs=16, Nodes=1
>
> * in calculate_order() called by each slab, the 2 loops of
> calc_slab_order() will all be meaningless due to slub_min_order
> is bigger than slub_max_order
>
> * prevent future code cleanup like in [2].
>
> Fix it by adding some sanity check to enforce the min/max semantics.
>
> [1]. https://lore.kernel.org/lkml/[email protected]/
> [2]. https://lore.kernel.org/lkml/[email protected]/
> Signed-off-by: Feng Tang <[email protected]>
Thanks, applied!
> ---
> mm/slub.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index f7940048138c..b36e5eb0ccb7 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4711,6 +4711,9 @@ static int __init setup_slub_min_order(char *str)
> {
> get_option(&str, (int *)&slub_min_order);
>
> + if (slub_min_order > slub_max_order)
> + slub_max_order = slub_min_order;
> +
> return 1;
> }
>
> @@ -4721,6 +4724,9 @@ static int __init setup_slub_max_order(char *str)
> get_option(&str, (int *)&slub_max_order);
> slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);
>
> + if (slub_min_order > slub_max_order)
> + slub_min_order = slub_max_order;
> +
> return 1;
> }
>