util/bpf_skel/bperf_follower.bpf.c

0001 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
0002 // Copyright (c) 2021 Facebook
0003 #include "vmlinux.h"
0004 #include <bpf/bpf_helpers.h>
0005 #include <bpf/bpf_tracing.h>
0006 #include "bperf_u.h"
0007
0008 struct {
0009     __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
0010     __uint(key_size, sizeof(__u32));
0011     __uint(value_size, sizeof(struct bpf_perf_event_value));
0012     __uint(max_entries, 1);
0013 } diff_readings SEC(".maps");
0014
0015 struct {
0016     __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
0017     __uint(key_size, sizeof(__u32));
0018     __uint(value_size, sizeof(struct bpf_perf_event_value));
0019     __uint(max_entries, 1);
0020 } accum_readings SEC(".maps");
0021
0022 struct {
0023     __uint(type, BPF_MAP_TYPE_HASH);
0024     __uint(key_size, sizeof(__u32));
0025     __uint(value_size, sizeof(__u32));
0026 } filter SEC(".maps");
0027
0028 enum bperf_filter_type type = 0;
0029 int enabled = 0;
0030
0031 SEC("fexit/XXX")
0032 int BPF_PROG(fexit_XXX)
0033 {
0034     struct bpf_perf_event_value *diff_val, *accum_val;
0035     __u32 filter_key, zero = 0;
0036     __u32 *accum_key;
0037
0038     if (!enabled)
0039         return 0;
0040
0041     switch (type) {
0042     case BPERF_FILTER_GLOBAL:
0043         accum_key = &zero;
0044         goto do_add;
0045     case BPERF_FILTER_CPU:
0046         filter_key = bpf_get_smp_processor_id();
0047         break;
0048     case BPERF_FILTER_PID:
0049         filter_key = bpf_get_current_pid_tgid() & 0xffffffff;
0050         break;
0051     case BPERF_FILTER_TGID:
0052         filter_key = bpf_get_current_pid_tgid() >> 32;
0053         break;
0054     default:
0055         return 0;
0056     }
0057
0058     accum_key = bpf_map_lookup_elem(&filter, &filter_key);
0059     if (!accum_key)
0060         return 0;
0061
0062 do_add:
0063     diff_val = bpf_map_lookup_elem(&diff_readings, &zero);
0064     if (!diff_val)
0065         return 0;
0066
0067     accum_val = bpf_map_lookup_elem(&accum_readings, accum_key);
0068     if (!accum_val)
0069         return 0;
0070
0071     accum_val->counter += diff_val->counter;
0072     accum_val->enabled += diff_val->enabled;
0073     accum_val->running += diff_val->running;
0074
0075     return 0;
0076 }
0077
0078 char LICENSE[] SEC("license") = "Dual BSD/GPL";