linux-kernel - [PATCH v5 6/8] x86/resctrl: Display CLOSID and RMID for the resctrl groups

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Message-ID: <168564611100.527584.7981937236207103115.stgit@bmoger-ubuntu>
Date:   Thu, 1 Jun 2023 14:01:51 -0500
From:   Babu Moger <babu.moger@....com>
To:     <corbet@....net>, <reinette.chatre@...el.com>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>
CC:     <fenghua.yu@...el.com>, <dave.hansen@...ux.intel.com>,
        <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
        <akpm@...ux-foundation.org>, <quic_neeraju@...cinc.com>,
        <rdunlap@...radead.org>, <damien.lemoal@...nsource.wdc.com>,
        <songmuchun@...edance.com>, <peterz@...radead.org>,
        <jpoimboe@...nel.org>, <pbonzini@...hat.com>, <babu.moger@....com>,
        <chang.seok.bae@...el.com>, <pawan.kumar.gupta@...ux.intel.com>,
        <jmattson@...gle.com>, <daniel.sneddon@...ux.intel.com>,
        <sandipan.das@....com>, <tony.luck@...el.com>,
        <james.morse@....com>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <bagasdotme@...il.com>,
        <eranian@...gle.com>, <christophe.leroy@...roup.eu>,
        <pawan.kumar.gupta@...ux.intel.com>, <jarkko@...nel.org>,
        <adrian.hunter@...el.com>, <quic_jiles@...cinc.com>,
        <peternewman@...gle.com>, <babu.moger@....com>
Subject: [PATCH v5 6/8] x86/resctrl: Display CLOSID and RMID for the resctrl
 groups

In x86, hardware uses CLOSID and an RMID to identify a control group and
a monitoring group respectively. When a user creates a control or monitor
group these details are not visible to the user. These details can help
to debug the issues.

Add CLOSID(ctrl_hw_id) and RMID(mon_hw_id) to the control/monitor groups
display in resctrl interface. Users can see these details when mounted
with "-o debug" option.

For example:
 $cat /sys/fs/resctrl/ctrl_grp1/ctrl_hw_id
 1
 $cat /sys/fs/resctrl/mon_groups/mon_grp1/mon_hw_id
 3

Signed-off-by: Babu Moger <babu.moger@....com>
---
 Documentation/arch/x86/resctrl.rst     |    8 ++++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   44 ++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index afdee4d1f691..1baf857ad8c6 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -344,6 +344,10 @@ When control is enabled all CTRL_MON groups will also contain:
 	file. On successful pseudo-locked region creation the mode will
 	automatically change to "pseudo-locked".
 
+"ctrl_hw_id":
+	Available only with debug option. The identifier used by hardware
+	for the control group. On x86 this is the CLOSID.
+
 When monitoring is enabled all MON groups will also contain:
 
 "mon_data":
@@ -357,6 +361,10 @@ When monitoring is enabled all MON groups will also contain:
 	the sum for all tasks in the CTRL_MON group and all tasks in
 	MON groups. Please see example section for more details on usage.
 
+"mon_hw_id":
+	Available only with debug option. The identifier used by hardware
+	for the monitor group. On x86 this is the RMID.
+
 Resource allocation rules
 -------------------------
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index be91dea5f927..2f5cdc638607 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -763,6 +763,38 @@ static int rdtgroup_tasks_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+static int rdtgroup_closid_show(struct kernfs_open_file *of,
+				struct seq_file *s, void *v)
+{
+	struct rdtgroup *rdtgrp;
+	int ret = 0;
+
+	rdtgrp = rdtgroup_kn_lock_live(of->kn);
+	if (rdtgrp)
+		seq_printf(s, "%u\n", rdtgrp->closid);
+	else
+		ret = -ENOENT;
+	rdtgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
+static int rdtgroup_rmid_show(struct kernfs_open_file *of,
+			      struct seq_file *s, void *v)
+{
+	struct rdtgroup *rdtgrp;
+	int ret = 0;
+
+	rdtgrp = rdtgroup_kn_lock_live(of->kn);
+	if (rdtgrp)
+		seq_printf(s, "%u\n", rdtgrp->mon.rmid);
+	else
+		ret = -ENOENT;
+	rdtgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
 #ifdef CONFIG_PROC_CPU_RESCTRL
 
 /*
@@ -1824,6 +1856,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= rdtgroup_tasks_show,
 		.fflags		= RFTYPE_BASE,
 	},
+	{
+		.name		= "mon_hw_id",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_rmid_show,
+	},
 	{
 		.name		= "schemata",
 		.mode		= 0644,
@@ -1847,6 +1885,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= rdtgroup_size_show,
 		.fflags		= RFTYPE_CTRL_BASE,
 	},
+	{
+		.name		= "ctrl_hw_id",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_closid_show,
+	},
 
 };