linux-kernel - [PATCH v7 2/4] x86/resctrl: Add mount option to pick input event for mba

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Message-ID: <20241003191228.67541-3-tony.luck@intel.com>
Date: Thu,  3 Oct 2024 12:12:26 -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 2/4] x86/resctrl: Add mount option to pick input event for mba_MBps mode

Add a new mount option "mba_MBps_event={event_name}" where event_name
is one of "mbm_local_bytes" or "mbm_total_bytes" that allows a user to
specify which monitoring event to use. Do not allow both options at
the same time.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/kernel/cpu/resctrl/internal.h |  1 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 49 ++++++++++++++++++++------
 2 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 955999aecfca..b3d4fc80a496 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -102,6 +102,7 @@ struct rdt_fs_context {
 	bool				enable_cdpl2;
 	bool				enable_cdpl3;
 	bool				enable_mba_mbps;
+	enum resctrl_event_id		mba_mbps_event;
 	bool				enable_debug;
 };
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index aedb30120d50..606cf635ea94 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2343,7 +2343,7 @@ 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);
 }
@@ -2521,7 +2521,7 @@ static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 	}
 
 	if (ctx->enable_mba_mbps) {
-		r->membw.mba_mbps_event = QOS_L3_MBM_LOCAL_EVENT_ID;
+		r->membw.mba_mbps_event = ctx->mba_mbps_event;
 		ret = set_mba_sc(true);
 		if (ret)
 			goto out_cdpl3;
@@ -2739,15 +2739,17 @@ enum rdt_param {
 	Opt_cdp,
 	Opt_cdpl2,
 	Opt_mba_mbps,
+	Opt_mba_mbps_event,
 	Opt_debug,
 	nr__rdt_params
 };
 
 static const struct fs_parameter_spec rdt_fs_parameters[] = {
-	fsparam_flag("cdp",		Opt_cdp),
-	fsparam_flag("cdpl2",		Opt_cdpl2),
-	fsparam_flag("mba_MBps",	Opt_mba_mbps),
-	fsparam_flag("debug",		Opt_debug),
+	fsparam_flag("cdp",			Opt_cdp),
+	fsparam_flag("cdpl2",			Opt_cdpl2),
+	fsparam_flag("mba_MBps",		Opt_mba_mbps),
+	fsparam_string("mba_MBps_event",	Opt_mba_mbps_event),
+	fsparam_flag("debug",			Opt_debug),
 	{}
 };
 
@@ -2770,9 +2772,25 @@ 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";
-		if (!supports_mba_mbps())
+		msg = "mba_MBps requires MBM and linear scale MBA at L3 scope";
+		if (!supports_mba_mbps() || ctx->enable_mba_mbps)
 			return invalfc(fc, msg);
+		if (is_mbm_local_enabled())
+			ctx->mba_mbps_event = QOS_L3_MBM_LOCAL_EVENT_ID;
+		else
+			return invalfc(fc, msg);
+		ctx->enable_mba_mbps = true;
+		return 0;
+	case Opt_mba_mbps_event:
+		msg = "mba_MBps requires MBM and linear scale MBA at L3 scope";
+		if (!supports_mba_mbps() || ctx->enable_mba_mbps)
+			return invalfc(fc, msg);
+		if (!strcmp("mbm_local_bytes", param->string))
+			ctx->mba_mbps_event = QOS_L3_MBM_LOCAL_EVENT_ID;
+		else if (!strcmp("mbm_total_bytes", param->string))
+			ctx->mba_mbps_event = QOS_L3_MBM_TOTAL_EVENT_ID;
+		else
+			return invalfc(fc, "unknown MBM event %s", param->string);
 		ctx->enable_mba_mbps = true;
 		return 0;
 	case Opt_debug:
@@ -3931,16 +3949,27 @@ static int rdtgroup_rename(struct kernfs_node *kn,
 	return ret;
 }
 
+static const char *mba_sc_event_opt_name(struct rdt_resource *r)
+{
+	if (r->membw.mba_mbps_event == QOS_L3_MBM_LOCAL_EVENT_ID)
+		return ",mba_MBps_event=mbm_local_bytes";
+	else if (r->membw.mba_mbps_event == QOS_L3_MBM_TOTAL_EVENT_ID)
+		return ",mba_MBps_event=mbm_total_bytes";
+	return "";
+}
+
 static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
 {
+	struct rdt_resource *r_mba = &rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl;
+
 	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
 		seq_puts(seq, ",cdp");
 
 	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
 		seq_puts(seq, ",cdpl2");
 
-	if (is_mba_sc(&rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl))
-		seq_puts(seq, ",mba_MBps");
+	if (is_mba_sc(r_mba))
+		seq_puts(seq, mba_sc_event_opt_name(r_mba));
 
 	if (resctrl_debug)
 		seq_puts(seq, ",debug");
-- 
2.46.1