From e519ce7a26b4c877d834e4234e8d24478448c0d3 Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Wed, 20 Sep 2023 15:44:13 +0800 Subject: mm/slub: add sanity check for slub_min/max_order cmdline setup 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/21a0ba8b-bf05-0799-7c78-2a35f8c8d52a@os.amperecomputing.com/ [2]. https://lore.kernel.org/lkml/20230908145302.30320-7-vbabka@suse.cz/ Signed-off-by: Feng Tang Signed-off-by: Vlastimil Babka --- mm/slub.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'mm/slub.c') 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; } -- cgit v1.2.3