x86/resctrl: Display RMID of resource group

In x86, hardware uses RMID to identify a monitoring group. When a user
creates a monitor group these details are not visible. These details
can help resctrl debugging.

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

Add RFTYPE_MON_BASE that complements existing RFTYPE_CTRL_BASE and
represents files belonging to monitoring groups.

Other architectures do not use "RMID". Use the name mon_hw_id to refer
to "RMID" in an effort to keep the naming generic.

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

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Peter Newman <peternewman@google.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Tan Shaopeng <tan.shaopeng@jp.fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-10-babu.moger@amd.com

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 7412252f95a7d48d20af88c478b44dde8f95f66d..a6279df64a9db8aa69dd08d8643e9cc9b7c42da7 100644 (file)
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -376,6 +376,10 @@ 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/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index b816b902b5c05849b703572a98bee17bba0d2ba2..a4f1aa15f0a2a8d38de404aa4cb539359f3bbe8c 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -254,6 +254,7 @@ struct rdtgroup {
 #define RFTYPE_MON_INFO                        (RFTYPE_INFO | RFTYPE_MON)
 #define RFTYPE_TOP_INFO                        (RFTYPE_INFO | RFTYPE_TOP)
 #define RFTYPE_CTRL_BASE               (RFTYPE_BASE | RFTYPE_CTRL)
+#define RFTYPE_MON_BASE                        (RFTYPE_BASE | RFTYPE_MON)
 
 /* List of all resource groups */
 extern struct list_head rdt_all_groups;

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 5f6d6ba63a2e8d77c94d4d9c4cab46162f2d8aa3..69a1de92384ab26a4b7eef9063e857121a7f4f1d 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -795,6 +795,22 @@ static int rdtgroup_closid_show(struct kernfs_open_file *of,
        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
 
 /*
@@ -1867,6 +1883,13 @@ 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,
+               .fflags         = RFTYPE_MON_BASE | RFTYPE_DEBUG,
+       },
        {
                .name           = "schemata",
                .mode           = 0644,