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).
>
> 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()".
> + * @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?
> +}
> +
> +/**
> + * 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()"?
> + * @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.
> + 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?
> + }
> +
> + return 0;
return void?
> +}
> +
> +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"?
> + 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.
> + 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.
> + }
> +
> + 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"
> + }
> +
> + 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.
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.
> + 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
