| Message ID | 20230920074413.1361547-1-feng.tang@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/slub: add sanity check for slub_min/max_order cmdline setup | expand |
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/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 <feng.tang@intel.com> 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; > } >
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; }
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 <feng.tang@intel.com> --- mm/slub.c | 6 ++++++ 1 file changed, 6 insertions(+)