Commit 141cb5c4 authored by Tony Luck's avatar Tony Luck Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Make mba_sc use total bandwidth if local is not supported 



The default input measurement to the mba_sc feedback loop for memory bandwidth
control when the user mounts with the "mba_MBps" option is the local bandwidth
event. But some systems may not support a local bandwidth event.

When local bandwidth event is not supported, check for support of total
bandwidth and use that instead.

Relax the mount option check to allow use of the "mba_MBps" option for systems
when only total bandwidth monitoring is supported. Also update the error
message.

Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20241206163148.83828-6-tony.luck@intel.com
parent 2c272fad

arch/x86/kernel/cpu/resctrl/core.c

+2 −0
Original line number Diff line number Diff line
@@ -965,6 +965,8 @@ static __init bool get_rdt_mon_resources(void) 


	if (is_mbm_local_enabled())

		mba_mbps_default_event = QOS_L3_MBM_LOCAL_EVENT_ID;

	else if (is_mbm_total_enabled())

		mba_mbps_default_event = QOS_L3_MBM_TOTAL_EVENT_ID;



	return !rdt_get_mon_l3_config(r);

}

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+2 −2
Original line number Diff line number Diff line
@@ -2341,7 +2341,7 @@ static bool supports_mba_mbps(void) 
	struct rdt_resource *rmbm = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;

	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;



	return (is_mbm_local_enabled() &&

	return (is_mbm_enabled() &&

		r->alloc_capable && is_mba_linear() &&

		r->ctrl_scope == rmbm->mon_scope);

}
@@ -2768,7 +2768,7 @@ static int rdt_parse_param(struct fs_context *fc, struct fs_parameter *param) 
		ctx->enable_cdpl2 = true;

		return 0;

	case Opt_mba_mbps:

		msg = "mba_MBps requires local MBM and linear scale MBA at L3 scope";

		msg = "mba_MBps requires MBM and linear scale MBA at L3 scope";

		if (!supports_mba_mbps())

			return invalfc(fc, msg);

		ctx->enable_mba_mbps = true;