linux-kernel - [PATCH v13 08/10] x86/resctrl: Display CLOSID for resource group

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Message-ID: <20231013202602.2492645-9-babu.moger@amd.com>
Date:   Fri, 13 Oct 2023 15:26:00 -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>,
        <jarkko@...nel.org>, <adrian.hunter@...el.com>,
        <quic_jiles@...cinc.com>, <peternewman@...gle.com>
Subject: [PATCH v13 08/10] x86/resctrl: Display CLOSID for resource group

In x86, hardware uses CLOSID to identify a control group. When a user
creates a control group this information is not visible to the user.
It can help resctrl debugging.

Add CLOSID(ctrl_hw_id) to the control groups display in resctrl
interface. Users can see this detail when resctrl is mounted with
"-o debug" option.

Other architectures do not use "CLOSID". Use the names ctrl_hw_id
to refer to "CLOSID" in an effort to keep the naming generic.

For example:
 $cat /sys/fs/resctrl/ctrl_grp1/ctrl_hw_id
 1

Signed-off-by: Babu Moger <babu.moger@....com>
Tested-by: Peter Newman <peternewman@...gle.com>
Reviewed-by: Peter Newman <peternewman@...gle.com>
Tested-by: Tan Shaopeng <tan.shaopeng@...fujitsu.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@...fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@...el.com>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
v13: No changes.

v12: Moved the comments about RFTYPE_DEBUG to resctrl.rst. (Boris)
---
 Documentation/arch/x86/resctrl.rst     |  7 +++++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 23 +++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 0438880e38c5..07225d9c0b0f 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -359,6 +359,10 @@ 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":
@@ -436,6 +440,9 @@ RESCTRL filesystem has two main components
 		-> RFTYPE_CTRL (Files for CTRL group)
 		   Files: mode, schemata, size
 
+			-> RFTYPE_DEBUG (Files to help resctrl debugging)
+			   File: ctrl_hw_id
+
 Resource allocation rules
 -------------------------
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 84e0f45578dd..5814a0bf3cea 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -779,6 +779,22 @@ 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;
+}
+
 #ifdef CONFIG_PROC_CPU_RESCTRL
 
 /*
@@ -1881,6 +1897,13 @@ static struct rftype res_common_files[] = {
 		.seq_show	= rdt_has_sparse_bitmasks_show,
 		.fflags		= RFTYPE_CTRL_INFO | RFTYPE_RES_CACHE,
 	},
+	{
+		.name		= "ctrl_hw_id",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_closid_show,
+		.fflags		= RFTYPE_CTRL_BASE | RFTYPE_DEBUG,
+	},
 
 };
 
-- 
2.34.1