sched_ext: Provides a sysfs 'events' to expose core event counters

Add a sysfs entry at /sys/kernel/sched_ext/root/events to expose core
event counters through the files system interface. Each line of the file
shows the event name and its counter value.

In addition, the format of scx_dump_event() is adjusted as the event name
gets longer.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 2e1a1e4fc3044d3ace073a4c1f1af4ae5ccce75c..aec098efd6fbca965f81b55e0123aaaba265862e 100644 (file)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1576,7 +1576,7 @@ static DEFINE_PER_CPU(struct scx_event_stats, event_stats_cpu);
  * @kind: a kind of event to dump
  */
 #define scx_dump_event(s, events, kind) do {                                   \
-       dump_line(&(s), "%30s: %16llu", #kind, (events)->kind);                 \
+       dump_line(&(s), "%40s: %16llu", #kind, (events)->kind);                 \
 } while (0)
 
 
@@ -4383,8 +4383,33 @@ static ssize_t scx_attr_ops_show(struct kobject *kobj,
 }
 SCX_ATTR(ops);
 
+#define scx_attr_event_show(buf, at, events, kind) ({                          \
+       sysfs_emit_at(buf, at, "%s %llu\n", #kind, (events)->kind);             \
+})
+
+static ssize_t scx_attr_events_show(struct kobject *kobj,
+                                   struct kobj_attribute *ka, char *buf)
+{
+       struct scx_event_stats events;
+       int at = 0;
+
+       scx_bpf_events(&events, sizeof(events));
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_SELECT_CPU_FALLBACK);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_DISPATCH_KEEP_LAST);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_ENQ_SKIP_EXITING);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_ENQ_SKIP_MIGRATION_DISABLED);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_ENQ_SLICE_DFL);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_BYPASS_DURATION);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_BYPASS_DISPATCH);
+       at += scx_attr_event_show(buf, at, &events, SCX_EV_BYPASS_ACTIVATE);
+       return at;
+}
+SCX_ATTR(events);
+
 static struct attribute *scx_sched_attrs[] = {
        &scx_attr_ops.attr,
+       &scx_attr_events.attr,
        NULL,
 };
 ATTRIBUTE_GROUPS(scx_sched);