[PATCH v18 28/33] fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group

Babu Moger posted 33 patches 4 days, 8 hours ago
[PATCH v18 28/33] fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group
Posted by Babu Moger 4 days, 8 hours ago
Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and
MON resource groups to display the counter assignment states of the
resource group when "mbm_event" counter assignment mode is enabled.

Display the list in the following format:
<Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state>

Event: A valid MBM event listed in
       /sys/fs/resctrl/info/L3_MON/event_configs directory.

Domain ID: A valid domain ID.

The assignment state can be one of the following:

_ : No counter assigned.

e : Counter assigned exclusively.

Example:
To list the assignment states for the default group
$ cd /sys/fs/resctrl
$ cat /sys/fs/resctrl/mbm_L3_assignments
mbm_total_bytes:0=e;1=e
mbm_local_bytes:0=e;1=e

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v18: Moved documentation of "mbm_L3_assignments" just after mon_hw_id.

v17: Moved mbm_L3_assignments_show() to fs/resctrl/monitor.c.
     mbm_cntr_get() can stay static.
     Minor change in changelog for imperative mode.
     Fixed the return error for consistancy.

v16: Fixed minor merge conflicts with code displacement.
     Changed the check with mbm_cntr_get() to "< 0" from " >=".

v15: Updated the changelog with Reinette's text.
     Updated the event format list to list multiple domains.
     Changed the goto out_assing to out_unlock.
     Updated to use new loop for_each_mon_event() instead of hardcoding.

v14: Added missed rdtgroup_kn_lock_live on failure case.
     Updated the user doc resctrl.rst to clarify counter assignments.
     Updated the changelog.

v13: Changelog update.
     Few changes in mbm_L3_assignments_show() after moving the event config to evt_list.
     Resolved conflicts caused by the recent FS/ARCH code restructure.
     The rdtgroup.c/monitor.c files have been split between the FS and ARCH directories.

v12: New patch:
     Assignment interface moved inside the group based the discussion
     https://lore.kernel.org/lkml/CALPaoCiii0vXOF06mfV=kVLBzhfNo0SFqt4kQGwGSGVUqvr2Dg@mail.gmail.com/#t
---
 Documentation/filesystems/resctrl.rst | 31 +++++++++++++++++
 fs/resctrl/internal.h                 |  2 ++
 fs/resctrl/monitor.c                  | 49 +++++++++++++++++++++++++++
 fs/resctrl/rdtgroup.c                 |  6 ++++
 4 files changed, 88 insertions(+)

diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 1de815b3a07b..a2b7240b0818 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -509,6 +509,37 @@ When monitoring is enabled all MON groups will also contain:
 	Available only with debug option. The identifier used by hardware
 	for the monitor group. On x86 this is the RMID.
 
+When monitoring is enabled all MON groups may also contain:
+
+"mbm_L3_assignments":
+	Exists when "mbm_event" counter assignment mode is supported and lists the
+	counter assignment states of the group.
+
+	The assignment list is displayed in the following format:
+
+	<Event>:<Domain ID>=<Assignment state>;<Domain ID>=<Assignment state>
+
+	Event: A valid MBM event in the
+	       /sys/fs/resctrl/info/L3_MON/event_configs directory.
+
+	Domain ID: A valid domain ID.
+
+	Assignment states:
+
+	_ : No counter assigned.
+
+	e : Counter assigned exclusively.
+
+	Example:
+
+	To display the counter assignment states for the default group.
+	::
+
+	 # cd /sys/fs/resctrl
+	 # cat /sys/fs/resctrl/mbm_L3_assignments
+	   mbm_total_bytes:0=e;1=e
+	   mbm_local_bytes:0=e;1=e
+
 When the "mba_MBps" mount option is used all CTRL_MON groups will also contain:
 
 "mba_MBps_event":
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 9be1e53a73d3..88079ca0d57a 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -416,6 +416,8 @@ int resctrl_mbm_assign_on_mkdir_show(struct kernfs_open_file *of,
 ssize_t resctrl_mbm_assign_on_mkdir_write(struct kernfs_open_file *of, char *buf,
 					  size_t nbytes, loff_t off);
 
+int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
+
 #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
 int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
 
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 13af138d4b3b..e8c3b3a7987b 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -1456,6 +1456,54 @@ int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+int mbm_L3_assignments_show(struct kernfs_open_file *of, struct seq_file *s, void *v)
+{
+	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+	struct rdt_mon_domain *d;
+	struct rdtgroup *rdtgrp;
+	struct mon_evt *mevt;
+	int ret = 0;
+	bool sep;
+
+	rdtgrp = rdtgroup_kn_lock_live(of->kn);
+	if (!rdtgrp) {
+		ret = -ENOENT;
+		goto out_unlock;
+	}
+
+	rdt_last_cmd_clear();
+	if (!resctrl_arch_mbm_cntr_assign_enabled(r)) {
+		rdt_last_cmd_puts("mbm_event counter assignment mode is not enabled\n");
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	for_each_mon_event(mevt) {
+		if (mevt->rid != r->rid || !mevt->enabled || !resctrl_is_mbm_event(mevt->evtid))
+			continue;
+
+		sep = false;
+		seq_printf(s, "%s:", mevt->name);
+		list_for_each_entry(d, &r->mon_domains, hdr.list) {
+			if (sep)
+				seq_putc(s, ';');
+
+			if (mbm_cntr_get(r, d, rdtgrp, mevt->evtid) < 0)
+				seq_printf(s, "%d=_", d->hdr.id);
+			else
+				seq_printf(s, "%d=e", d->hdr.id);
+
+			sep = true;
+		}
+		seq_putc(s, '\n');
+	}
+
+out_unlock:
+	rdtgroup_kn_unlock(of->kn);
+
+	return ret;
+}
+
 /**
  * resctrl_mon_resource_init() - Initialise global monitoring structures.
  *
@@ -1514,6 +1562,7 @@ int resctrl_mon_resource_init(void)
 		resctrl_file_fflags_init("event_filter", RFTYPE_ASSIGN_CONFIG);
 		resctrl_file_fflags_init("mbm_assign_on_mkdir", RFTYPE_MON_INFO |
 					 RFTYPE_RES_CACHE);
+		resctrl_file_fflags_init("mbm_L3_assignments", RFTYPE_MON_BASE);
 	}
 
 	return 0;
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 48f98146c099..519aa6acef5b 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1937,6 +1937,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= event_filter_show,
 		.write		= event_filter_write,
 	},
+	{
+		.name		= "mbm_L3_assignments",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= mbm_L3_assignments_show,
+	},
 	{
 		.name		= "mbm_assign_mode",
 		.mode		= 0444,
-- 
2.34.1
Re: [PATCH v18 28/33] fs/resctrl: Introduce mbm_L3_assignments to list assignments in a group
Posted by Reinette Chatre 4 days, 1 hour ago
Hi Babu,

On 9/5/25 2:34 PM, Babu Moger wrote:
> Introduce the mbm_L3_assignments resctrl file associated with CTRL_MON and
> MON resource groups to display the counter assignment states of the
> resource group when "mbm_event" counter assignment mode is enabled.
> 
> Display the list in the following format:
> <Event>:<Domain id>=<Assignment state>;<Domain id>=<Assignment state>
> 
> Event: A valid MBM event listed in
>        /sys/fs/resctrl/info/L3_MON/event_configs directory.
> 
> Domain ID: A valid domain ID.
> 
> The assignment state can be one of the following:
> 
> _ : No counter assigned.
> 
> e : Counter assigned exclusively.
> 
> Example:
> To list the assignment states for the default group
> $ cd /sys/fs/resctrl
> $ cat /sys/fs/resctrl/mbm_L3_assignments
> mbm_total_bytes:0=e;1=e
> mbm_local_bytes:0=e;1=e
> 
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Reinette