[PATCH v4 6/7] x86/resctrl: Display CLOSID and RMID for the resctrl groups

[Babu Moger]

When a user creates a control or monitor group, the CLOSID or RMID
are not visible to the user. It can help to debug the issues in some
cases. There are only available with "-o debug" option.

Add CLOSID(ctrl_hw_id) and RMID(mon_hw_id) to the control/monitor groups
display in resctrl interface.
$cat /sys/fs/resctrl/clos1/clos_hw_id
1
$cat /sys/fs/resctrl/mon_groups/mon1/mon_hw_id
3

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
 Documentation/x86/resctrl.rst          |   17 ++++++++++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   44 ++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
index be443251b484..5aff8c2beb08 100644
--- a/Documentation/x86/resctrl.rst
+++ b/Documentation/x86/resctrl.rst
@@ -345,6 +345,14 @@ 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. On x86, reading this file shows
+	the Class of Service (CLOS) id which acts as a resource control
+	tag on which the resources can be throttled. Kernel assigns a new
+	CLOSID a control group is created depending on the available
+	CLOSIDs. Multiple cores(or threads) or processes can share a
+	same CLOSID in a resctrl group.
+
 When monitoring is enabled all MON groups will also contain:
 
 "mon_data":
@@ -358,6 +366,15 @@ 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. On x86, reading this file shows
+	the Resource Monitoring ID (RMID) for monitoring the resource
+	utilization. Monitoring is performed by tagging each core (or
+	thread) or process via a RMID. Kernel assigns a new RMID when
+	a group is created depending on the available RMIDs. Multiple
+	cores (or threads) or processes can share a same RMID in a
+	resctrl group.
+
 Resource allocation rules
 -------------------------
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 0169821bc08c..15ded0dd5b09 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -782,6 +782,38 @@ 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
 
 /*
@@ -1843,6 +1875,12 @@ 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,
@@ -1866,6 +1904,12 @@ 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,
+	},
 
 };