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author | Yonghong Song <yhs@fb.com> | 2018-01-04 13:55:04 -0800 |
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committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-01-06 23:52:23 +0100 |
commit | 3ced9b600234e6bb13cb25654ce44c4896485cf2 (patch) | |
tree | 33efbd17272bf7e54425103a21e7b31856bc7683 /tools/testing/selftests/bpf/test_stacktrace_map.c | |
parent | bpf: implement syscall command BPF_MAP_GET_NEXT_KEY for stacktrace map (diff) | |
download | linux-dev-3ced9b600234e6bb13cb25654ce44c4896485cf2.tar.xz linux-dev-3ced9b600234e6bb13cb25654ce44c4896485cf2.zip |
tools/bpf: add a bpf selftest for stacktrace
Added a bpf selftest in test_progs at tools directory for stacktrace.
The test will populate a hashtable map and a stacktrace map
at the same time with the same key, stackid.
The user space will compare both maps, using BPF_MAP_LOOKUP_ELEM
command and BPF_MAP_GET_NEXT_KEY command, to ensure that both have
the same set of keys.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/bpf/test_stacktrace_map.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_stacktrace_map.c b/tools/testing/selftests/bpf/test_stacktrace_map.c new file mode 100644 index 000000000000..76d85c5d08bd --- /dev/null +++ b/tools/testing/selftests/bpf/test_stacktrace_map.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include <linux/bpf.h> +#include "bpf_helpers.h" + +#ifndef PERF_MAX_STACK_DEPTH +#define PERF_MAX_STACK_DEPTH 127 +#endif + +struct bpf_map_def SEC("maps") control_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 1, +}; + +struct bpf_map_def SEC("maps") stackid_hmap = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 10000, +}; + +struct bpf_map_def SEC("maps") stackmap = { + .type = BPF_MAP_TYPE_STACK_TRACE, + .key_size = sizeof(__u32), + .value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH, + .max_entries = 10000, +}; + +/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ +struct sched_switch_args { + unsigned long long pad; + char prev_comm[16]; + int prev_pid; + int prev_prio; + long long prev_state; + char next_comm[16]; + int next_pid; + int next_prio; +}; + +SEC("tracepoint/sched/sched_switch") +int oncpu(struct sched_switch_args *ctx) +{ + __u32 key = 0, val = 0, *value_p; + + value_p = bpf_map_lookup_elem(&control_map, &key); + if (value_p && *value_p) + return 0; /* skip if non-zero *value_p */ + + /* The size of stackmap and stackid_hmap should be the same */ + key = bpf_get_stackid(ctx, &stackmap, 0); + if ((int)key >= 0) + bpf_map_update_elem(&stackid_hmap, &key, &val, 0); + + return 0; +} + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */ |