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Message-ID: <df408cca8a500713b8a7e49ed5a95d9ccc54c48e.1747349530.git.babu.moger@amd.com>
Date: Thu, 15 May 2025 17:52:00 -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: <james.morse@....com>, <dave.martin@....com>, <fenghuay@...dia.com>,
<x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
<akpm@...ux-foundation.org>, <thuth@...hat.com>, <rostedt@...dmis.org>,
<ardb@...nel.org>, <gregkh@...uxfoundation.org>,
<daniel.sneddon@...ux.intel.com>, <jpoimboe@...nel.org>,
<alexandre.chartre@...cle.com>, <pawan.kumar.gupta@...ux.intel.com>,
<thomas.lendacky@....com>, <perry.yuan@....com>, <seanjc@...gle.com>,
<kai.huang@...el.com>, <xiaoyao.li@...el.com>, <babu.moger@....com>,
<kan.liang@...ux.intel.com>, <xin3.li@...el.com>, <ebiggers@...gle.com>,
<xin@...or.com>, <sohil.mehta@...el.com>, <andrew.cooper3@...rix.com>,
<mario.limonciello@....com>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <peternewman@...gle.com>,
<maciej.wieczor-retman@...el.com>, <eranian@...gle.com>,
<Xiaojian.Du@....com>, <gautham.shenoy@....com>
Subject: [PATCH v13 15/27] x86/resctrl: Report 'Unassigned' for MBM events in mbm_cntr_assign mode
In mbm_cntr_assign mode, the hardware counter should be assigned to read
the MBM events.
Report 'Unassigned' in case the user attempts to read the event without
assigning a hardware counter.
Export resctrl_is_mbm_event() and mbm_cntr_get() to allow usage from other
functions within fs/resctrl.
Signed-off-by: Babu Moger <babu.moger@....com>
---
v13: Minor commitlog and user doc update.
Resolved conflicts caused by the recent FS/ARCH code restructure.
The monitor.c/rdtgroup.c files have been split between the FS and ARCH directories.
v12: Updated the documentation for more clarity.
v11: Domain can be NULL with SNC support so moved the unassign check in
rdtgroup_mondata_show().
v10: Moved the code to check the assign state inside mon_event_read().
Fixed few text comments.
v9: Used is_mbm_event() to check the event type.
Minor user documentation update.
v8: Used MBM_EVENT_ARRAY_INDEX to get the index for the MBM event.
Documentation update to make the text generic.
v7: Moved the documentation under "mon_data".
Updated the text little bit.
v6: Added more explaination in the resctrl.rst
Added checks to detect "Unassigned" before reading RMID.
v5: New patch.
---
Documentation/filesystems/resctrl.rst | 8 ++++++++
fs/resctrl/ctrlmondata.c | 14 ++++++++++++++
fs/resctrl/internal.h | 2 ++
fs/resctrl/monitor.c | 4 ++--
fs/resctrl/rdtgroup.c | 2 +-
include/linux/resctrl.h | 1 +
6 files changed, 28 insertions(+), 3 deletions(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 2bfad43aac9c..5cf2d742f04c 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -430,6 +430,14 @@ When monitoring is enabled all MON groups will also contain:
for the L3 cache they occupy). These are named "mon_sub_L3_YY"
where "YY" is the node number.
+ The mbm_cntr_assign mode offers "num_mbm_cntrs" number of counters
+ and allows users to assign a counter to mon_hw_id, event pair enabling
+ bandwidth monitoring for as long as the counter remains assigned.
+ The hardware will continue tracking the assigned mon_hw_id until
+ the user manually unassigns it, ensuring that counters are not reset
+ during this period. An MBM event returns 'Unassigned' when the event
+ does not have a hardware counter assigned.
+
"mon_hw_id":
Available only with debug option. The identifier used by hardware
for the monitor group. On x86 this is the RMID.
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 6ed2dfd4dbbd..f6b8ad24b0b5 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -643,6 +643,18 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
goto out;
}
d = container_of(hdr, struct rdt_mon_domain, hdr);
+
+ /*
+ * Report 'Unassigned' if mbm_cntr_assign mode is enabled and
+ * counter is unassigned.
+ */
+ if (resctrl_arch_mbm_cntr_assign_enabled(r) &&
+ resctrl_is_mbm_event(evtid) &&
+ (mbm_cntr_get(r, d, rdtgrp, evtid) < 0)) {
+ rr.err = -ENOENT;
+ goto checkresult;
+ }
+
mon_event_read(&rr, r, d, rdtgrp, &d->hdr.cpu_mask, evtid, false);
}
@@ -652,6 +664,8 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
seq_puts(m, "Error\n");
else if (rr.err == -EINVAL)
seq_puts(m, "Unavailable\n");
+ else if (rr.err == -ENOENT)
+ seq_puts(m, "Unassigned\n");
else
seq_printf(m, "%llu\n", rr.val);
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 64ddc107fcab..0dfd2efe68fc 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -381,6 +381,8 @@ int resctrl_assign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
struct rdtgroup *rdtgrp, enum resctrl_event_id evtid);
int resctrl_unassign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
struct rdtgroup *rdtgrp, enum resctrl_event_id evtid);
+int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, enum resctrl_event_id evtid);
#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 fbc938bd3b23..c98a61bde179 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -956,8 +956,8 @@ static void resctrl_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d
* mbm_cntr_get() - Return the cntr_id for the matching evtid and rdtgrp in
* cntr_cfg array.
*/
-static int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
- struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
+int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
+ struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
{
int cntr_id;
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index f192b2736a77..72317a5adee2 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -127,7 +127,7 @@ static bool resctrl_is_mbm_enabled(void)
resctrl_arch_is_mbm_local_enabled());
}
-static bool resctrl_is_mbm_event(int e)
+bool resctrl_is_mbm_event(int e)
{
return (e >= QOS_L3_MBM_TOTAL_EVENT_ID &&
e <= QOS_L3_MBM_LOCAL_EVENT_ID);
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 59a4fe60ab46..f78b6064230c 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -441,6 +441,7 @@ static inline u32 resctrl_get_config_index(u32 closid,
}
}
+bool resctrl_is_mbm_event(int e);
bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level l);
int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable);
--
2.34.1
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