1 files changed, 48 insertions, 14 deletions

diff --git a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
index 292c430768b5..c2298a2decc9 100644
--- a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
+++ b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
@@ -1,14 +1,12 @@
 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 // Copyright (c) 2021 Facebook
 // Copyright (c) 2021 Google
+#include "bperf_cgroup.h"
 #include "vmlinux.h"
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_core_read.h>
 
-#define MAX_LEVELS  10  // max cgroup hierarchy level: arbitrary
-#define MAX_EVENTS  32  // max events per cgroup: arbitrary
-
 // NOTE: many of map and global data will be modified before loading
 //       from the userspace (perf tool) using the skeleton helpers.
 
@@ -43,11 +41,39 @@ struct {
 	__uint(value_size, sizeof(struct bpf_perf_event_value));
 } cgrp_readings SEC(".maps");
 
+/* new kernel cgroup definition */
+struct cgroup___new {
+	int level;
+	struct cgroup *ancestors[];
+} __attribute__((preserve_access_index));
+
+/* old kernel cgroup definition */
+struct cgroup___old {
+	int level;
+	u64 ancestor_ids[];
+} __attribute__((preserve_access_index));
+
 const volatile __u32 num_events = 1;
 const volatile __u32 num_cpus = 1;
+const volatile int use_cgroup_v2 = 0;
 
 int enabled = 0;
-int use_cgroup_v2 = 0;
+int perf_subsys_id = -1;
+
+static inline __u64 get_cgroup_v1_ancestor_id(struct cgroup *cgrp, int level)
+{
+	/* recast pointer to capture new type for compiler */
+	struct cgroup___new *cgrp_new = (void *)cgrp;
+
+	if (bpf_core_field_exists(cgrp_new->ancestors)) {
+		return BPF_CORE_READ(cgrp_new, ancestors[level], kn, id);
+	} else {
+		/* recast pointer to capture old type for compiler */
+		struct cgroup___old *cgrp_old = (void *)cgrp;
+
+		return BPF_CORE_READ(cgrp_old, ancestor_ids[level]);
+	}
+}
 
 static inline int get_cgroup_v1_idx(__u32 *cgrps, int size)
 {
@@ -58,17 +84,25 @@ static inline int get_cgroup_v1_idx(__u32 *cgrps, int size)
 	int level;
 	int cnt;
 
-	cgrp = BPF_CORE_READ(p, cgroups, subsys[perf_event_cgrp_id], cgroup);
+	if (perf_subsys_id == -1) {
+#if __has_builtin(__builtin_preserve_enum_value)
+		perf_subsys_id = bpf_core_enum_value(enum cgroup_subsys_id,
+						     perf_event_cgrp_id);
+#else
+		perf_subsys_id = perf_event_cgrp_id;
+#endif
+	}
+	cgrp = BPF_CORE_READ(p, cgroups, subsys[perf_subsys_id], cgroup);
 	level = BPF_CORE_READ(cgrp, level);
 
-	for (cnt = 0; i < MAX_LEVELS; i++) {
+	for (cnt = 0; i < BPERF_CGROUP__MAX_LEVELS; i++) {
 		__u64 cgrp_id;
 
 		if (i > level)
 			break;
 
 		// convert cgroup-id to a map index
-		cgrp_id = BPF_CORE_READ(cgrp, ancestor_ids[i]);
+		cgrp_id = get_cgroup_v1_ancestor_id(cgrp, i);
 		elem = bpf_map_lookup_elem(&cgrp_idx, &cgrp_id);
 		if (!elem)
 			continue;
@@ -87,7 +121,7 @@ static inline int get_cgroup_v2_idx(__u32 *cgrps, int size)
 	__u32 *elem;
 	int cnt;
 
-	for (cnt = 0; i < MAX_LEVELS; i++) {
+	for (cnt = 0; i < BPERF_CGROUP__MAX_LEVELS; i++) {
 		__u64 cgrp_id = bpf_get_current_ancestor_cgroup_id(i);
 
 		if (cgrp_id == 0)
@@ -112,17 +146,17 @@ static int bperf_cgroup_count(void)
 	register int c = 0;
 	struct bpf_perf_event_value val, delta, *prev_val, *cgrp_val;
 	__u32 cpu = bpf_get_smp_processor_id();
-	__u32 cgrp_idx[MAX_LEVELS];
+	__u32 cgrp_idx[BPERF_CGROUP__MAX_LEVELS];
 	int cgrp_cnt;
 	__u32 key, cgrp;
 	long err;
 
 	if (use_cgroup_v2)
-		cgrp_cnt = get_cgroup_v2_idx(cgrp_idx, MAX_LEVELS);
+		cgrp_cnt = get_cgroup_v2_idx(cgrp_idx, BPERF_CGROUP__MAX_LEVELS);
 	else
-		cgrp_cnt = get_cgroup_v1_idx(cgrp_idx, MAX_LEVELS);
+		cgrp_cnt = get_cgroup_v1_idx(cgrp_idx, BPERF_CGROUP__MAX_LEVELS);
 
-	for ( ; idx < MAX_EVENTS; idx++) {
+	for ( ; idx < BPERF_CGROUP__MAX_EVENTS; idx++) {
 		if (idx == num_events)
 			break;
 
@@ -150,7 +184,7 @@ static int bperf_cgroup_count(void)
 			delta.enabled = val.enabled - prev_val->enabled;
 			delta.running = val.running - prev_val->running;
 
-			for (c = 0; c < MAX_LEVELS; c++) {
+			for (c = 0; c < BPERF_CGROUP__MAX_LEVELS; c++) {
 				if (c == cgrp_cnt)
 					break;
 
@@ -176,7 +210,7 @@ static int bperf_cgroup_count(void)
 }
 
 // This will be attached to cgroup-switches event for each cpu
-SEC("perf_events")
+SEC("perf_event")
 int BPF_PROG(on_cgrp_switch)
 {
 	return bperf_cgroup_count();