mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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3677d0a131
For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing kprobe tracing programs with libbbpf
bpf loader.
- For kprobe events pointing to system calls, the SYSCALL() macro in
trace_common.h was used.
- Adding a kprobe event and attaching a bpf program to it was done
through bpf_program_attach().
- Instead of using the existing BPF MAP definition, MAP definition
has been refactored with the new BTF-defined MAP format.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com
131 lines
2.6 KiB
C
131 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
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* Copyright (c) 2015 BMW Car IT GmbH
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <bpf/libbpf.h>
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#include <bpf/bpf.h>
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#define MAX_ENTRIES 20
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#define MAX_CPU 4
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#define MAX_STARS 40
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struct cpu_hist {
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long data[MAX_ENTRIES];
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long max;
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};
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static struct cpu_hist cpu_hist[MAX_CPU];
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static void stars(char *str, long val, long max, int width)
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{
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int i;
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for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
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str[i] = '*';
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if (val > max)
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str[i - 1] = '+';
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str[i] = '\0';
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}
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static void print_hist(void)
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{
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char starstr[MAX_STARS];
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struct cpu_hist *hist;
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int i, j;
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/* clear screen */
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printf("\033[2J");
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for (j = 0; j < MAX_CPU; j++) {
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hist = &cpu_hist[j];
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/* ignore CPUs without data (maybe offline?) */
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if (hist->max == 0)
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continue;
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printf("CPU %d\n", j);
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printf(" latency : count distribution\n");
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for (i = 1; i <= MAX_ENTRIES; i++) {
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stars(starstr, hist->data[i - 1], hist->max, MAX_STARS);
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printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
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(1l << i) >> 1, (1l << i) - 1,
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hist->data[i - 1], MAX_STARS, starstr);
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}
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}
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}
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static void get_data(int fd)
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{
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long key, value;
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int c, i;
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for (i = 0; i < MAX_CPU; i++)
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cpu_hist[i].max = 0;
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for (c = 0; c < MAX_CPU; c++) {
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for (i = 0; i < MAX_ENTRIES; i++) {
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key = c * MAX_ENTRIES + i;
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bpf_map_lookup_elem(fd, &key, &value);
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cpu_hist[c].data[i] = value;
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if (value > cpu_hist[c].max)
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cpu_hist[c].max = value;
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}
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}
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}
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int main(int argc, char **argv)
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{
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struct bpf_link *links[2];
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struct bpf_program *prog;
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struct bpf_object *obj;
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char filename[256];
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int map_fd, i = 0;
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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obj = bpf_object__open_file(filename, NULL);
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if (libbpf_get_error(obj)) {
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fprintf(stderr, "ERROR: opening BPF object file failed\n");
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return 0;
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}
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/* load BPF program */
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if (bpf_object__load(obj)) {
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fprintf(stderr, "ERROR: loading BPF object file failed\n");
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goto cleanup;
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}
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map_fd = bpf_object__find_map_fd_by_name(obj, "my_lat");
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if (map_fd < 0) {
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fprintf(stderr, "ERROR: finding a map in obj file failed\n");
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goto cleanup;
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}
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bpf_object__for_each_program(prog, obj) {
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links[i] = bpf_program__attach(prog);
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if (libbpf_get_error(links[i])) {
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fprintf(stderr, "ERROR: bpf_program__attach failed\n");
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links[i] = NULL;
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goto cleanup;
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}
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i++;
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}
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while (1) {
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get_data(map_fd);
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print_hist();
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sleep(5);
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}
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cleanup:
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for (i--; i >= 0; i--)
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bpf_link__destroy(links[i]);
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bpf_object__close(obj);
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return 0;
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}
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