linux-kernel - [PATCH v7 3/4] x86/resctrl: Use total bandwidth for mba

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Message-ID: <20241003191228.67541-4-tony.luck@intel.com>
Date: Thu,  3 Oct 2024 12:12:27 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Peter Newman <peternewman@...gle.com>,
	Jonathan Corbet <corbet@....net>,
	Shuah Khan <skhan@...uxfoundation.org>,
	x86@...nel.org
Cc: Shaopeng Tan <tan.shaopeng@...itsu.com>,
	James Morse <james.morse@....com>,
	Jamie Iles <quic_jiles@...cinc.com>,
	Babu Moger <babu.moger@....com>,
	Randy Dunlap <rdunlap@...radead.org>,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org,
	patches@...ts.linux.dev,
	Tony Luck <tony.luck@...el.com>
Subject: [PATCH v7 3/4] x86/resctrl: Use total bandwidth for mba_MBps option when local isn't present

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.

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@...el.com>
---
 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 606cf635ea94..433daaa4d125 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2777,6 +2777,8 @@ static int rdt_parse_param(struct fs_context *fc, struct fs_parameter *param)
 			return invalfc(fc, msg);
 		if (is_mbm_local_enabled())
 			ctx->mba_mbps_event = QOS_L3_MBM_LOCAL_EVENT_ID;
+		else if (is_mbm_total_enabled())
+			ctx->mba_mbps_event = QOS_L3_MBM_TOTAL_EVENT_ID;
 		else
 			return invalfc(fc, msg);
 		ctx->enable_mba_mbps = true;
-- 
2.46.1