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Message-ID: <dc097e5caa1c7df42c211fffb67f8d860a6b39da.1749848715.git.babu.moger@amd.com>
Date: Fri, 13 Jun 2025 16:05:09 -0500
From: Babu Moger <babu.moger@....com>
To: <babu.moger@....com>, <corbet@....net>, <tony.luck@...el.com>,
<reinette.chatre@...el.com>, <Dave.Martin@....com>, <james.morse@....com>,
<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <akpm@...ux-foundation.org>,
<rostedt@...dmis.org>, <paulmck@...nel.org>, <thuth@...hat.com>,
<ardb@...nel.org>, <gregkh@...uxfoundation.org>, <seanjc@...gle.com>,
<thomas.lendacky@....com>, <pawan.kumar.gupta@...ux.intel.com>,
<manali.shukla@....com>, <perry.yuan@....com>, <kai.huang@...el.com>,
<peterz@...radead.org>, <xiaoyao.li@...el.com>, <kan.liang@...ux.intel.com>,
<mario.limonciello@....com>, <xin3.li@...el.com>, <gautham.shenoy@....com>,
<xin@...or.com>, <chang.seok.bae@...el.com>, <fenghuay@...dia.com>,
<peternewman@...gle.com>, <maciej.wieczor-retman@...el.com>,
<eranian@...gle.com>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH v14 25/32] fs/resctrl: Provide interface to update the event configurations
When assignable counters are supported the users can modify the event
configuration by writing to the 'event_filter' interface file. The event
configurations for mbm_event mode are located in
/sys/fs/resctrl/info/L3_MON/event_configs/.
Update the assignments of all groups when the event configuration is
modified.
Example:
$ mount -t resctrl resctrl /sys/fs/resctrl
$ cd /sys/fs/resctrl/
$ cat info/L3_MON/event_configs/mbm_local_bytes/event_filter
local_reads,local_non_temporal_writes,local_reads_slow_memory
$ echo "local_reads,local_non_temporal_writes" >
info/L3_MON/event_configs/mbm_total_bytes/event_filter
$ cat info/L3_MON/event_configs/mbm_total_bytes/event_filter
local_reads,local_non_temporal_writes
Signed-off-by: Babu Moger <babu.moger@....com>
---
v14: Passed struct mon_evt where applicable instead of just the event type.
Fixed few text corrections about memory trasaction type.
Renamed few functions resctrl_group_assign() -> rdtgroup_assign_cntr()
resctrl_update_assign() -> resctrl_assign_cntr_allrdtgrp()
Removed few extra bases.
v13: Updated changelog for imperative mode.
Added function description in the prototype.
Updated the user doc resctrl.rst to address few feedback.
Resolved conflicts caused by the recent FS/ARCH code restructure.
The rdtgroup.c/monitor.c file has now been split between the FS and ARCH directories.
v12: New patch to modify event configurations.
---
Documentation/filesystems/resctrl.rst | 12 +++
fs/resctrl/rdtgroup.c | 120 +++++++++++++++++++++++++-
2 files changed, 131 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index b1db1a53db2a..2cd6107ca452 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -342,6 +342,18 @@ with the following files:
# cat /sys/fs/resctrl/info/L3_MON/event_configs/mbm_local_bytes/event_filter
local_reads, local_non_temporal_writes, local_reads_slow_memory
+ Modify the event configuration by writing to the "event_filter" file within the
+ configuration directory. The read/write event_filter file contains the configuration
+ of the event that reflects which memory transactions are counted by it.
+
+ For example::
+
+ # echo "local_reads, local_non_temporal_writes" >
+ /sys/fs/resctrl/info/L3_MON/counter_configs/mbm_total_bytes/event_filter
+
+ # cat /sys/fs/resctrl/info/L3_MON/counter_configs/mbm_total_bytes/event_filter
+ local_reads, local_non_temporal_writes
+
"max_threshold_occupancy":
Read/write file provides the largest value (in
bytes) at which a previously used LLC_occupancy
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index e2fa5e10c2dd..fdea608e0796 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1928,6 +1928,123 @@ static int event_filter_show(struct kernfs_open_file *of, struct seq_file *seq,
return 0;
}
+/**
+ * rdtgroup_assign_cntr - Update the counter assignments for the event in
+ * a group.
+ * @r: Resource to which update needs to be done.
+ * @rdtgrp: Resctrl group.
+ * @mevt: MBM monitor event.
+ */
+static int rdtgroup_assign_cntr(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+ struct mon_evt *mevt)
+{
+ struct rdt_mon_domain *d;
+ int cntr_id;
+
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ cntr_id = mbm_cntr_get(r, d, rdtgrp, mevt->evtid);
+ if (cntr_id >= 0 && d->cntr_cfg[cntr_id].evt_cfg != mevt->evt_cfg) {
+ d->cntr_cfg[cntr_id].evt_cfg = mevt->evt_cfg;
+ resctrl_arch_config_cntr(r, d, mevt->evtid, rdtgrp->mon.rmid,
+ rdtgrp->closid, cntr_id, true);
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * resctrl_assign_cntr_allrdtgrp - Update the counter assignments for the event
+ * for all the groups.
+ * @r: Resource to which update needs to be done.
+ * @mevt MBM Monitor event.
+ */
+static void resctrl_assign_cntr_allrdtgrp(struct rdt_resource *r, struct mon_evt *mevt)
+{
+ struct rdtgroup *prgrp, *crgrp;
+
+ /*
+ * Check all the groups where the event tyoe is assigned and update
+ * the assignment
+ */
+ list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
+ rdtgroup_assign_cntr(r, prgrp, mevt);
+
+ list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list)
+ rdtgroup_assign_cntr(r, crgrp, mevt);
+ }
+}
+
+static int resctrl_process_configs(char *tok, u32 *val)
+{
+ char *evt_str;
+ u32 temp_val;
+ bool found;
+ int i;
+
+next_config:
+ if (!tok || tok[0] == '\0')
+ return 0;
+
+ /* Start processing the strings for each memory transaction type */
+ evt_str = strim(strsep(&tok, ","));
+ found = false;
+ for (i = 0; i < NUM_MBM_EVT_VALUES; i++) {
+ if (!strcmp(mbm_config_values[i].name, evt_str)) {
+ temp_val = mbm_config_values[i].val;
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ rdt_last_cmd_printf("Invalid memory transaction type %s\n", evt_str);
+ return -EINVAL;
+ }
+
+ *val |= temp_val;
+
+ goto next_config;
+}
+
+static ssize_t event_filter_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+ struct mon_evt *mevt = rdt_kn_parent_priv(of->kn);
+ u32 evt_cfg = 0;
+ int ret = 0;
+
+ /* Valid input requires a trailing newline */
+ if (nbytes == 0 || buf[nbytes - 1] != '\n')
+ return -EINVAL;
+
+ buf[nbytes - 1] = '\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_cntr_assign mode is not enabled\n");
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ ret = resctrl_process_configs(buf, &evt_cfg);
+ if (!ret && mevt->evt_cfg != evt_cfg) {
+ mevt->evt_cfg = evt_cfg;
+ resctrl_assign_cntr_allrdtgrp(r, mevt);
+ }
+
+out_unlock:
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+
+ return ret ?: nbytes;
+}
+
/* rdtgroup information files for one cache resource. */
static struct rftype res_common_files[] = {
{
@@ -2054,9 +2171,10 @@ static struct rftype res_common_files[] = {
},
{
.name = "event_filter",
- .mode = 0444,
+ .mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.seq_show = event_filter_show,
+ .write = event_filter_write,
},
{
.name = "mbm_assign_mode",
--
2.34.1
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