[PATCH v3 23/46] perf/core: hooks to add architecture specific features in perf_cgroup

[David Carrillo-Cisneros]

The hooks allows architectures to extend the behavior of the perf cgroup.

In this patch series, the hooks are used to allow intel_cmt to follow
changes in the perf_cgroup hierarchy.

Signed-off-by: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
---
 include/linux/perf_event.h | 11 +++++++++++
 kernel/events/core.c       | 12 ++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 14dff7a..9f388d4 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1386,4 +1386,15 @@ int perf_event_exit_cpu(unsigned int cpu);
 #define perf_event_exit_cpu	NULL
 #endif
 
+/*
+ * Hooks for architecture specific extensions for perf_cgroup.
+ */
+#ifndef perf_cgroup_arch_css_online
+# define perf_cgroup_arch_css_online(css) 0
+#endif
+
+#ifndef perf_cgroup_arch_css_offline
+# define perf_cgroup_arch_css_offline(css) do { } while (0)
+#endif
+
 #endif /* _LINUX_PERF_EVENT_H */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 464f46d..e11a16a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10748,6 +10748,16 @@ perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
 	return &jc->css;
 }
 
+static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+	return perf_cgroup_arch_css_online(css);
+}
+
+static void perf_cgroup_css_offline(struct cgroup_subsys_state *css)
+{
+	perf_cgroup_arch_css_offline(css);
+}
+
 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
 {
 	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
@@ -10776,6 +10786,8 @@ static void perf_cgroup_attach(struct cgroup_taskset *tset)
 
 struct cgroup_subsys perf_event_cgrp_subsys = {
 	.css_alloc	= perf_cgroup_css_alloc,
+	.css_online	= perf_cgroup_css_online,
+	.css_offline	= perf_cgroup_css_offline,
 	.css_free	= perf_cgroup_css_free,
 	.attach		= perf_cgroup_attach,
 };
-- 
2.8.0.rc3.226.g39d4020