samples: bpf: Refactor tracepoint tracing programs with libbpf

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 tracepoint tracing programs with libbbpf
bpf loader.

    - Adding a tracepoint 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/20200823085334.9413-4-danieltimlee@gmail.com

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index c74d477..a6d3646 100644 (file)
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -74,7 +74,7 @@ tracex7-objs := tracex7_user.o
 test_probe_write_user-objs := test_probe_write_user_user.o
 trace_output-objs := trace_output_user.o $(TRACE_HELPERS)
 lathist-objs := lathist_user.o
-offwaketime-objs := bpf_load.o offwaketime_user.o $(TRACE_HELPERS)
+offwaketime-objs := offwaketime_user.o $(TRACE_HELPERS)
 spintest-objs := spintest_user.o $(TRACE_HELPERS)
 map_perf_test-objs := map_perf_test_user.o
 test_overhead-objs := bpf_load.o test_overhead_user.o
@@ -100,8 +100,8 @@ xdp_redirect_map-objs := xdp_redirect_map_user.o
 xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o
 xdp_monitor-objs := bpf_load.o xdp_monitor_user.o
 xdp_rxq_info-objs := xdp_rxq_info_user.o
-syscall_tp-objs := bpf_load.o syscall_tp_user.o
-cpustat-objs := bpf_load.o cpustat_user.o
+syscall_tp-objs := syscall_tp_user.o
+cpustat-objs := cpustat_user.o
 xdp_adjust_tail-objs := xdp_adjust_tail_user.o
 xdpsock-objs := xdpsock_user.o
 xdp_fwd-objs := xdp_fwd_user.o

diff --git a/samples/bpf/cpustat_kern.c b/samples/bpf/cpustat_kern.c
index a86a19d..5aefd19 100644 (file)
--- a/samples/bpf/cpustat_kern.c
+++ b/samples/bpf/cpustat_kern.c
@@ -51,28 +51,28 @@ static int cpu_opps[] = { 208000, 432000, 729000, 960000, 1200000 };
 #define MAP_OFF_PSTATE_IDX     3
 #define MAP_OFF_NUM            4
 
-struct bpf_map_def SEC("maps") my_map = {
-       .type = BPF_MAP_TYPE_ARRAY,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(u64),
-       .max_entries = MAX_CPU * MAP_OFF_NUM,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __type(key, u32);
+       __type(value, u64);
+       __uint(max_entries, MAX_CPU * MAP_OFF_NUM);
+} my_map SEC(".maps");
 
 /* cstate_duration records duration time for every idle state per CPU */
-struct bpf_map_def SEC("maps") cstate_duration = {
-       .type = BPF_MAP_TYPE_ARRAY,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(u64),
-       .max_entries = MAX_CPU * MAX_CSTATE_ENTRIES,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __type(key, u32);
+       __type(value, u64);
+       __uint(max_entries, MAX_CPU * MAX_CSTATE_ENTRIES);
+} cstate_duration SEC(".maps");
 
 /* pstate_duration records duration time for every operating point per CPU */
-struct bpf_map_def SEC("maps") pstate_duration = {
-       .type = BPF_MAP_TYPE_ARRAY,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(u64),
-       .max_entries = MAX_CPU * MAX_PSTATE_ENTRIES,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __type(key, u32);
+       __type(value, u64);
+       __uint(max_entries, MAX_CPU * MAX_PSTATE_ENTRIES);
+} pstate_duration SEC(".maps");
 
 /*
  * The trace events for cpu_idle and cpu_frequency are taken from:

diff --git a/samples/bpf/cpustat_user.c b/samples/bpf/cpustat_user.c
index 869a994..9667598 100644 (file)
--- a/samples/bpf/cpustat_user.c
+++ b/samples/bpf/cpustat_user.c
@@ -9,7 +9,6 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
-#include <linux/bpf.h>
 #include <locale.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -18,7 +17,9 @@
 #include <sys/wait.h>
 
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
+
+static int cstate_map_fd, pstate_map_fd;
 
 #define MAX_CPU                        8
 #define MAX_PSTATE_ENTRIES     5
@@ -181,21 +182,50 @@ static void int_exit(int sig)
 {
        cpu_stat_inject_cpu_idle_event();
        cpu_stat_inject_cpu_frequency_event();
-       cpu_stat_update(map_fd[1], map_fd[2]);
+       cpu_stat_update(cstate_map_fd, pstate_map_fd);
        cpu_stat_print();
        exit(0);
 }
 
 int main(int argc, char **argv)
 {
+       struct bpf_link *link = NULL;
+       struct bpf_program *prog;
+       struct bpf_object *obj;
        char filename[256];
        int ret;
 
        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+       obj = bpf_object__open_file(filename, NULL);
+       if (libbpf_get_error(obj)) {
+               fprintf(stderr, "ERROR: opening BPF object file failed\n");
+               return 0;
+       }
 
-       if (load_bpf_file(filename)) {
-               printf("%s", bpf_log_buf);
-               return 1;
+       prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+       if (!prog) {
+               printf("finding a prog in obj file failed\n");
+               goto cleanup;
+       }
+
+       /* load BPF program */
+       if (bpf_object__load(obj)) {
+               fprintf(stderr, "ERROR: loading BPF object file failed\n");
+               goto cleanup;
+       }
+
+       cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");
+       pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");
+       if (cstate_map_fd < 0 || pstate_map_fd < 0) {
+               fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+               goto cleanup;
+       }
+
+       link = bpf_program__attach(prog);
+       if (libbpf_get_error(link)) {
+               fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+               link = NULL;
+               goto cleanup;
        }
 
        ret = cpu_stat_inject_cpu_idle_event();
@@ -210,10 +240,13 @@ int main(int argc, char **argv)
        signal(SIGTERM, int_exit);
 
        while (1) {
-               cpu_stat_update(map_fd[1], map_fd[2]);
+               cpu_stat_update(cstate_map_fd, pstate_map_fd);
                cpu_stat_print();
                sleep(5);
        }
 
+cleanup:
+       bpf_link__destroy(link);
+       bpf_object__close(obj);
        return 0;
 }

diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c
index e74ee1c..14b7929 100644 (file)
--- a/samples/bpf/offwaketime_kern.c
+++ b/samples/bpf/offwaketime_kern.c
@@ -28,38 +28,38 @@ struct key_t {
        u32 tret;
 };
 
-struct bpf_map_def SEC("maps") counts = {
-       .type = BPF_MAP_TYPE_HASH,
-       .key_size = sizeof(struct key_t),
-       .value_size = sizeof(u64),
-       .max_entries = 10000,
-};
-
-struct bpf_map_def SEC("maps") start = {
-       .type = BPF_MAP_TYPE_HASH,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(u64),
-       .max_entries = 10000,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_HASH);
+       __type(key, struct key_t);
+       __type(value, u64);
+       __uint(max_entries, 10000);
+} counts SEC(".maps");
+
+struct {
+       __uint(type, BPF_MAP_TYPE_HASH);
+       __type(key, u32);
+       __type(value, u64);
+       __uint(max_entries, 10000);
+} start SEC(".maps");
 
 struct wokeby_t {
        char name[TASK_COMM_LEN];
        u32 ret;
 };
 
-struct bpf_map_def SEC("maps") wokeby = {
-       .type = BPF_MAP_TYPE_HASH,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(struct wokeby_t),
-       .max_entries = 10000,
-};
-
-struct bpf_map_def SEC("maps") stackmap = {
-       .type = BPF_MAP_TYPE_STACK_TRACE,
-       .key_size = sizeof(u32),
-       .value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
-       .max_entries = 10000,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_HASH);
+       __type(key, u32);
+       __type(value, struct wokeby_t);
+       __uint(max_entries, 10000);
+} wokeby SEC(".maps");
+
+struct {
+       __uint(type, BPF_MAP_TYPE_STACK_TRACE);
+       __uint(key_size, sizeof(u32));
+       __uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
+       __uint(max_entries, 10000);
+} stackmap SEC(".maps");
 
 #define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
 

diff --git a/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c
index 51c7da5..5734cfd 100644 (file)
--- a/samples/bpf/offwaketime_user.c
+++ b/samples/bpf/offwaketime_user.c
@@ -5,19 +5,19 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <signal.h>
-#include <linux/bpf.h>
-#include <string.h>
 #include <linux/perf_event.h>
 #include <errno.h>
-#include <assert.h>
 #include <stdbool.h>
 #include <sys/resource.h>
 #include <bpf/libbpf.h>
-#include "bpf_load.h"
+#include <bpf/bpf.h>
 #include "trace_helpers.h"
 
 #define PRINT_RAW_ADDR 0
 
+/* counts, stackmap */
+static int map_fd[2];
+
 static void print_ksym(__u64 addr)
 {
        struct ksym *sym;
@@ -52,14 +52,14 @@ static void print_stack(struct key_t *key, __u64 count)
        int i;
 
        printf("%s;", key->target);
-       if (bpf_map_lookup_elem(map_fd[3], &key->tret, ip) != 0) {
+       if (bpf_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {
                printf("---;");
        } else {
                for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
                        print_ksym(ip[i]);
        }
        printf("-;");
-       if (bpf_map_lookup_elem(map_fd[3], &key->wret, ip) != 0) {
+       if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {
                printf("---;");
        } else {
                for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
@@ -96,23 +96,54 @@ static void int_exit(int sig)
 int main(int argc, char **argv)
 {
        struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+       struct bpf_object *obj = NULL;
+       struct bpf_link *links[2];
+       struct bpf_program *prog;
+       int delay = 1, i = 0;
        char filename[256];
-       int delay = 1;
-
-       snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-       setrlimit(RLIMIT_MEMLOCK, &r);
 
-       signal(SIGINT, int_exit);
-       signal(SIGTERM, int_exit);
+       if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+               perror("setrlimit(RLIMIT_MEMLOCK)");
+               return 1;
+       }
 
        if (load_kallsyms()) {
                printf("failed to process /proc/kallsyms\n");
                return 2;
        }
 
-       if (load_bpf_file(filename)) {
-               printf("%s", bpf_log_buf);
-               return 1;
+       snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+       obj = bpf_object__open_file(filename, NULL);
+       if (libbpf_get_error(obj)) {
+               fprintf(stderr, "ERROR: opening BPF object file failed\n");
+               obj = NULL;
+               goto cleanup;
+       }
+
+       /* load BPF program */
+       if (bpf_object__load(obj)) {
+               fprintf(stderr, "ERROR: loading BPF object file failed\n");
+               goto cleanup;
+       }
+
+       map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
+       map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
+       if (map_fd[0] < 0 || map_fd[1] < 0) {
+               fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+               goto cleanup;
+       }
+
+       signal(SIGINT, int_exit);
+       signal(SIGTERM, int_exit);
+
+       bpf_object__for_each_program(prog, obj) {
+               links[i] = bpf_program__attach(prog);
+               if (libbpf_get_error(links[i])) {
+                       fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+                       links[i] = NULL;
+                       goto cleanup;
+               }
+               i++;
        }
 
        if (argc > 1)
@@ -120,5 +151,10 @@ int main(int argc, char **argv)
        sleep(delay);
        print_stacks(map_fd[0]);
 
+cleanup:
+       for (i--; i >= 0; i--)
+               bpf_link__destroy(links[i]);
+
+       bpf_object__close(obj);
        return 0;
 }

diff --git a/samples/bpf/syscall_tp_kern.c b/samples/bpf/syscall_tp_kern.c
index 5a62b03..50231c2 100644 (file)
--- a/samples/bpf/syscall_tp_kern.c
+++ b/samples/bpf/syscall_tp_kern.c
@@ -18,19 +18,19 @@ struct syscalls_exit_open_args {
        long ret;
 };
 
-struct bpf_map_def SEC("maps") enter_open_map = {
-       .type = BPF_MAP_TYPE_ARRAY,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(u32),
-       .max_entries = 1,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __type(key, u32);
+       __type(value, u32);
+       __uint(max_entries, 1);
+} enter_open_map SEC(".maps");
 
-struct bpf_map_def SEC("maps") exit_open_map = {
-       .type = BPF_MAP_TYPE_ARRAY,
-       .key_size = sizeof(u32),
-       .value_size = sizeof(u32),
-       .max_entries = 1,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __type(key, u32);
+       __type(value, u32);
+       __uint(max_entries, 1);
+} exit_open_map SEC(".maps");
 
 static __always_inline void count(void *map)
 {

diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
index 57014ba..76a1d00 100644 (file)
--- a/samples/bpf/syscall_tp_user.c
+++ b/samples/bpf/syscall_tp_user.c
@@ -5,16 +5,12 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <stdlib.h>
-#include <signal.h>
-#include <linux/bpf.h>
 #include <string.h>
 #include <linux/perf_event.h>
 #include <errno.h>
-#include <assert.h>
-#include <stdbool.h>
 #include <sys/resource.h>
+#include <bpf/libbpf.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
 
 /* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
  * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
@@ -49,16 +45,44 @@ static void verify_map(int map_id)
 
 static int test(char *filename, int num_progs)
 {
-       int i, fd, map0_fds[num_progs], map1_fds[num_progs];
+       int map0_fds[num_progs], map1_fds[num_progs], fd, i, j = 0;
+       struct bpf_link *links[num_progs * 4];
+       struct bpf_object *objs[num_progs];
+       struct bpf_program *prog;
 
        for (i = 0; i < num_progs; i++) {
-               if (load_bpf_file(filename)) {
-                       fprintf(stderr, "%s", bpf_log_buf);
-                       return 1;
+               objs[i] = bpf_object__open_file(filename, NULL);
+               if (libbpf_get_error(objs[i])) {
+                       fprintf(stderr, "opening BPF object file failed\n");
+                       objs[i] = NULL;
+                       goto cleanup;
                }
-               printf("prog #%d: map ids %d %d\n", i, map_fd[0], map_fd[1]);
-               map0_fds[i] = map_fd[0];
-               map1_fds[i] = map_fd[1];
+
+               /* load BPF program */
+               if (bpf_object__load(objs[i])) {
+                       fprintf(stderr, "loading BPF object file failed\n");
+                       goto cleanup;
+               }
+
+               map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
+                                                             "enter_open_map");
+               map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
+                                                             "exit_open_map");
+               if (map0_fds[i] < 0 || map1_fds[i] < 0) {
+                       fprintf(stderr, "finding a map in obj file failed\n");
+                       goto cleanup;
+               }
+
+               bpf_object__for_each_program(prog, objs[i]) {
+                       links[j] = bpf_program__attach(prog);
+                       if (libbpf_get_error(links[j])) {
+                               fprintf(stderr, "bpf_program__attach failed\n");
+                               links[j] = NULL;
+                               goto cleanup;
+                       }
+                       j++;
+               }
+               printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]);
        }
 
        /* current load_bpf_file has perf_event_open default pid = -1
@@ -80,6 +104,12 @@ static int test(char *filename, int num_progs)
                verify_map(map1_fds[i]);
        }
 
+cleanup:
+       for (j--; j >= 0; j--)
+               bpf_link__destroy(links[j]);
+
+       for (i--; i >= 0; i--)
+               bpf_object__close(objs[i]);
        return 0;
 }