// 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 = 16384,}; 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 = 16384,}; struct bpf_map_def SEC("maps") stack_amap = {	.type = BPF_MAP_TYPE_ARRAY,	.key_size = sizeof(__u32),	.value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH,	.max_entries = 16384,}; /* 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";__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */