On Thu, Dec 7, 2023 at 11:56 AM Tony Luck <tony.luck@xxxxxxxxx> wrote: > > On Intel systems the memory bandwidth monitoring events are > independently enumerated. It is possible for a system to support > total memory bandwidth monitoring, but not support local bandwidth > monitoring. On such a system a user could not enable mba_sc mode. > Users will see this highly unhelpful error message from mount: > > # mount -t resctrl -o mba_MBps resctrl /sys/fs/resctrl > mount: /sys/fs/resctrl: wrong fs type, bad option, bad superblock on > resctrl, missing codepage or helper program, or other error. > dmesg(1) may have more information after failed mount system call. > > dmesg(1) does not provide any additional information. > > Modify the existing "mba_MBps" mount option to switch to total bandwidth > monitoring if local monitoring is not available. > > Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> > --- > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index 5f64a0b2597c..7410513db45a 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -2725,6 +2725,8 @@ static int rdt_parse_param(struct fs_context *fc, struct fs_parameter *param) > return -EINVAL; > if (is_mbm_local_enabled()) > ctx->enable_mba_mbps_local = true; > + else if (is_mbm_total_enabled()) > + ctx->enable_mba_mbps_total = true; > else > return -EINVAL; > return 0; > -- > 2.41.0 > Reviewed-by: Peter Newman <peternewman@xxxxxxxxxx>
