Hi Reinette,
On 5/22/2025 11:45 PM, Reinette Chatre wrote:
Hi Babu,
On 5/15/25 3:52 PM, Babu Moger wrote:
Users can modify the event configuration by writing to the event_filter
interface file. The event configurations for mbm_cntr_assign mode are
located in /sys/fs/resctrl/info/event_configs/.
heh ... looks like you also started thinking that "event_configs"
is a better name (also missing L3_MON).
Interesting... 'event_configs' seems to have made its way in somehow.
Alright, I’ll go ahead and add L3_MON."
Update the assignments of all groups when the event configuration is
modified.
Example:
$ cd /sys/fs/resctrl/
$ cat info/L3_MON/counter_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/counter_configs/mbm_total_bytes/event_filter
$ cat info/L3_MON/counter_configs/mbm_total_bytes/event_filter
local_reads,local_non_temporal_writes
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
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 4eb9f007ba3d..9923276826db 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
...
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index cf84e3a382ac..8c498b41be5d 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1930,6 +1930,123 @@ static int event_filter_show(struct kernfs_open_file *of, struct seq_file *seq,
return 0;
}
+/**
+ * resctrl_group_assign - Update the counter assignments for the event in
+ * a group.
This name is very generic with an unexpected namespace. "rdtgroup_" prefix
is often used for a function that operates on a rdtgroup. This can thus be
"rdtgroup_assign_cntr()".
Sure.
+ * @r: Resource to which update needs to be done.
+ * @rdtgrp: Resctrl group.
+ * @evtid: Event ID.
+ * @evt_cfg: Event configuration value.
+ */
+static int resctrl_group_assign(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+ enum resctrl_event_id evtid, u32 evt_cfg)
+{
+ 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, evtid);
+ if (cntr_id >= 0 && d->cntr_cfg[cntr_id].evt_cfg != evt_cfg) {
+ d->cntr_cfg[cntr_id].evt_cfg = evt_cfg;
+ resctrl_arch_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
+ rdtgrp->closid, cntr_id, evt_cfg, true);
+ }
+ }
+
+ return 0;
Can just return void?
sure.
+}
+
+/**
+ * resctrl_update_assign - Update the counter assignments for the event for all
+ * the groups.
Again very generic with "update" and "assign" that seem redundant? How about
"resctrl_assign_cntr_allrdtgrp()"?
Yes.
+ * @r: Resource to which update needs to be done.
+ * @evtid: Event ID.
+ * @evt_cfg: Event configuration value.
Why are both event ID and evt_cfg needed? Could just passing mon_evt simplify this?
+ */
+static int resctrl_update_assign(struct rdt_resource *r, enum resctrl_event_id evtid,
+ u32 evt_cfg)
+{
+ struct rdtgroup *prgrp, *crgrp;
+
+ /* Check if the cntr_id is associated to the event type updated */
Comment does not match code.
Will correct it.
+ list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
+ resctrl_group_assign(r, prgrp, evtid, evt_cfg);
+
+ list_for_each_entry(crgrp, &prgrp->mon.crdtgrp_list, mon.crdtgrp_list) {
+ resctrl_group_assign(r, crgrp, evtid, evt_cfg);
+ }
Unnecessary braces?
Yes.
+ }
+
+ return 0;
return void?
Sure.
+}
+
+static int resctrl_process_configs(char *tok, u32 *val)
+{
+ char *evt_str;
+ bool found;
+ int i;
+
+next_config:
+ if (!tok || tok[0] == '\0')
+ return 0;
+
+ /* Start processing the strings for each event type */
Does comment intend to describe one iteration or all iterations?
Also, "event type" -> "memory transaction"?
Sure.
+ evt_str = strim(strsep(&tok, ","));
+ found = false;
+ for (i = 0; i < NUM_MBM_EVT_VALUES; i++) {
+ if (!strcmp(mbm_evt_values[i].evt_name, evt_str)) {
+ *val |= mbm_evt_values[i].evt_val;
check spacing.
ok.
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ rdt_last_cmd_printf("Invalid event type %s\n", evt_str);
+ return -EINVAL;
Looks like this will return partially initialized data. Please use a local
variable in which to gather the new configuration and only assign that
to provided pointer on success.
Yes. Makes sense.
+ }
+
+ 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 unlock_out;
"grep goto fs/resctrl/rdtgroup.c"
Will change it to "out_unlock".
+ }
+
+ ret = resctrl_process_configs(buf, &evt_cfg);
+ if (!ret && mevt->evt_val != evt_cfg) {
+ mevt->evt_val = evt_cfg;
ah ... here it is. hmmm ... but it is mon_evt::evt_cfg, no? ah,
fixed in next patch.
Yea. My bad.
I still seem to be missing something because I expected mon_evt::evt_cfg
of mbm_total_bytes and mbm_local_bytes to be initialized with a starting
default. I missed where this is done in this series.
Its not done in this series. Will do in next revision.
+ resctrl_update_assign(r, mevt->evtid, evt_cfg);
+ }
+
+unlock_out:
+ mutex_unlock(&rdtgroup_mutex);
+ cpus_read_unlock();
+
+ return ret ?: nbytes;
+}
+
/* rdtgroup information files for one cache resource. */
static struct rftype res_common_files[] = {
{
@@ -2056,9 +2173,10 @@ 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",
Reinette
