// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook #include <vmlinux.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); __type(key, __u32); __type(value, 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[TASK_COMM_LEN]; int prev_pid; int prev_prio; long long prev_state; char next_comm[TASK_COMM_LEN]; 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";