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Message-ID: <1faeb40f2ad9170120ea9e676109c84f979a27ba.1755224735.git.babu.moger@amd.com>
Date: Thu, 14 Aug 2025 21:25:17 -0500
From: Babu Moger <babu.moger@....com>
To: <corbet@....net>, <tony.luck@...el.com>, <reinette.chatre@...el.com>,
<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
<dave.hansen@...ux.intel.com>
CC: <Dave.Martin@....com>, <james.morse@....com>, <babu.moger@....com>,
<x86@...nel.org>, <hpa@...or.com>, <akpm@...ux-foundation.org>,
<rostedt@...dmis.org>, <paulmck@...nel.org>,
<pawan.kumar.gupta@...ux.intel.com>, <kees@...nel.org>, <arnd@...db.de>,
<fvdl@...gle.com>, <seanjc@...gle.com>, <thomas.lendacky@....com>,
<yosry.ahmed@...ux.dev>, <xin@...or.com>, <sohil.mehta@...el.com>,
<kai.huang@...el.com>, <xiaoyao.li@...el.com>, <peterz@...radead.org>,
<mario.limonciello@....com>, <xin3.li@...el.com>, <perry.yuan@....com>,
<chang.seok.bae@...el.com>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <peternewman@...gle.com>,
<eranian@...gle.com>, <gautham.shenoy@....com>
Subject: [PATCH v17 13/33] fs/resctrl: Introduce interface to display number of free MBM counters
Introduce the "available_mbm_cntrs" resctrl file to display the number of
counters available for assignment in each domain when "mbm_event" mode is
enabled.
Signed-off-by: Babu Moger <babu.moger@....com>
---
v17: Moved resctrl_available_mbm_cntrs_show() to fs/resctrl/monitor.c.
Removed the Reviewed-by tag.
v16: Added Reviewed-by tag.
v15: Minor changelog text update.
Minor resctrl.rst text update and corrected the error text in
resctrl_available_mbm_cntrs_show().
Changed the goto label to out_unlock for consistency.
v14: Minor changelog update.
Changed subject line to fs/resctrl.
v13: Resolved conflicts caused by the recent FS/ARCH code restructure.
The files monitor.c and rdtgroup.c file has now been split between
the FS and ARCH directories.
v12: Minor change to change log.
Updated the documentation text with an example.
Replaced seq_puts(s, ";") with seq_putc(s, ';');
Added missing rdt_last_cmd_clear() in resctrl_available_mbm_cntrs_show().
v11: Rename rdtgroup_available_mbm_cntrs_show() to resctrl_available_mbm_cntrs_show().
Few minor text changes.
v10: Patch changed to handle the counters at domain level.
https://lore.kernel.org/lkml/CALPaoCj+zWq1vkHVbXYP0znJbe6Ke3PXPWjtri5AFgD9cQDCUg@mail.gmail.com/
So, display logic also changed now.
v9: New patch
---
Documentation/filesystems/resctrl.rst | 11 +++++++
fs/resctrl/internal.h | 3 ++
fs/resctrl/monitor.c | 44 +++++++++++++++++++++++++++
fs/resctrl/rdtgroup.c | 6 ++++
4 files changed, 64 insertions(+)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 4eb27530be6f..446736dbd97f 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -299,6 +299,17 @@ with the following files:
# cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
0=32;1=32
+"available_mbm_cntrs":
+ The number of counters available for assignment in each domain when mbm_event
+ mode is enabled on the system.
+
+ For example, on a system with 30 available [hardware] assignable counters
+ in each of its L3 domains:
+ ::
+
+ # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
+ 0=30;1=30
+
"max_threshold_occupancy":
Read/write file provides the largest value (in
bytes) at which a previously used LLC_occupancy
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index e4d7aa1a8fd1..35a8bad8ca75 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -388,6 +388,9 @@ int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of, struct seq_file *s
int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of, struct seq_file *s, void *v);
+int resctrl_available_mbm_cntrs_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 667770ecfd78..4185f2a4ba89 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -938,6 +938,48 @@ int resctrl_num_mbm_cntrs_show(struct kernfs_open_file *of,
return 0;
}
+int resctrl_available_mbm_cntrs_show(struct kernfs_open_file *of,
+ struct seq_file *s, void *v)
+{
+ struct rdt_resource *r = rdt_kn_parent_priv(of->kn);
+ struct rdt_mon_domain *dom;
+ bool sep = false;
+ u32 cntrs, i;
+ int ret = 0;
+
+ cpus_read_lock();
+ mutex_lock(&rdtgroup_mutex);
+
+ 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;
+ }
+
+ list_for_each_entry(dom, &r->mon_domains, hdr.list) {
+ if (sep)
+ seq_putc(s, ';');
+
+ cntrs = 0;
+ for (i = 0; i < r->mon.num_mbm_cntrs; i++) {
+ if (!dom->cntr_cfg[i].rdtgrp)
+ cntrs++;
+ }
+
+ seq_printf(s, "%d=%u", dom->hdr.id, cntrs);
+ sep = true;
+ }
+ seq_putc(s, '\n');
+
+out_unlock:
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+
+ return ret;
+}
+
/**
* resctrl_mon_resource_init() - Initialise global monitoring structures.
*
@@ -985,6 +1027,8 @@ int resctrl_mon_resource_init(void)
resctrl_enable_mon_event(QOS_L3_MBM_LOCAL_EVENT_ID);
resctrl_file_fflags_init("num_mbm_cntrs",
RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
+ resctrl_file_fflags_init("available_mbm_cntrs",
+ RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
}
return 0;
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index ce1c894dab18..8eaad45b28ea 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1822,6 +1822,12 @@ static struct rftype res_common_files[] = {
.seq_show = rdt_mon_features_show,
.fflags = RFTYPE_MON_INFO,
},
+ {
+ .name = "available_mbm_cntrs",
+ .mode = 0444,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = resctrl_available_mbm_cntrs_show,
+ },
{
.name = "num_rmids",
.mode = 0444,
--
2.34.1
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