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Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c new file mode 100644 index 000000000..00ed48672 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +#ifndef PERF_MAX_STACK_DEPTH +#define PERF_MAX_STACK_DEPTH 127 +#endif + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u32); +} control_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, 16384); + __type(key, __u32); + __type(value, __u32); +} stackid_hmap SEC(".maps"); + +typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH]; + +struct { + __uint(type, BPF_MAP_TYPE_STACK_TRACE); + __uint(max_entries, 16384); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(stack_trace_t)); +} stackmap SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 16384); + __type(key, __u32); + __type(value, stack_trace_t); +} stack_amap SEC(".maps"); + +/* 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 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64); + __u32 key = 0, val = 0, *value_p; + void *stack_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); + stack_p = bpf_map_lookup_elem(&stack_amap, &key); + if (stack_p) + bpf_get_stack(ctx, stack_p, max_len, 0); + } + + return 0; +} + +char _license[] SEC("license") = "GPL"; |