From: Namhyung Kim <namhyung@kernel.org>
To: Tejun Heo <tj@kernel.org>, Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-perf-users@vger.kernel.org,
Song Liu <songliubraving@fb.com>,
bpf@vger.kernel.org, Andrii Nakryiko <andrii@kernel.org>
Subject: [PATCH v2] perf stat: Support old kernels for bperf cgroup counting
Date: Mon, 10 Oct 2022 22:28:08 -0700 [thread overview]
Message-ID: <20221011052808.282394-1-namhyung@kernel.org> (raw)
In-Reply-To: <Y0Sx2KWX4gPlLytq@slm.duckdns.org>
The recent change in the cgroup will break the backward compatiblity in
the BPF program. It should support both old and new kernels using BPF
CO-RE technique.
Like the task_struct->__state handling in the offcpu analysis, we can
check the field name in the cgroup struct.
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/util/bpf_skel/bperf_cgroup.bpf.c | 29 ++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
index 435a87556688..6a438e0102c5 100644
--- a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
+++ b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
@@ -43,6 +43,18 @@ 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;
@@ -50,6 +62,21 @@ 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)
{
struct task_struct *p = (void *)bpf_get_current_task();
@@ -77,7 +104,7 @@ static inline int get_cgroup_v1_idx(__u32 *cgrps, int size)
break;
// convert cgroup-id to a map index
- cgrp_id = BPF_CORE_READ(cgrp, ancestors[i], kn, id);
+ cgrp_id = get_cgroup_v1_ancestor_id(cgrp, i);
elem = bpf_map_lookup_elem(&cgrp_idx, &cgrp_id);
if (!elem)
continue;
--
2.38.0.rc1.362.ged0d419d3c-goog
next prev parent reply other threads:[~2022-10-11 5:28 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-29 19:05 [PATCH cgroup/for-5.20] cgroup: Replace cgroup->ancestor_ids[] with ->ancestors[] Tejun Heo
2022-07-29 20:30 ` Namhyung Kim
2022-07-29 20:58 ` [PATCH v2 " Tejun Heo
2022-07-29 22:42 ` Michal Koutný
2022-07-29 23:02 ` Tejun Heo
2022-07-29 23:10 ` [PATCH v3 " Tejun Heo
2022-08-15 21:17 ` Tejun Heo
2022-09-22 4:05 ` Namhyung Kim
2022-09-22 4:14 ` [PATCH] perf stat: Support old kernels for bperf cgroup counting Namhyung Kim
2022-09-24 3:22 ` Tejun Heo
2022-09-30 20:30 ` Namhyung Kim
2022-09-30 21:43 ` Jiri Olsa
2022-09-30 21:56 ` Namhyung Kim
2022-09-30 22:00 ` Arnaldo Carvalho de Melo
2022-09-30 22:11 ` Namhyung Kim
2022-10-01 13:57 ` Jiri Olsa
2022-09-30 22:48 ` Andrii Nakryiko
2022-10-01 2:31 ` Namhyung Kim
2022-10-05 22:36 ` Andrii Nakryiko
2022-10-01 13:58 ` Jiri Olsa
2022-10-10 23:59 ` Tejun Heo
2022-10-11 5:24 ` Namhyung Kim
2022-10-11 5:28 ` Namhyung Kim [this message]
2022-10-11 16:53 ` [PATCH v2] " Tejun Heo
2022-10-14 13:27 ` Arnaldo Carvalho de Melo
2022-10-14 13:30 ` Arnaldo Carvalho de Melo
2022-10-14 16:40 ` Tejun Heo
2022-10-14 17:10 ` Arnaldo Carvalho de Melo
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