* [PATCH bpf-next v3 0/2] Refactor perf_event sample user program with libbpf bpf_link
@ 2020-03-13 11:52 Daniel T. Lee
2020-03-13 11:52 ` [PATCH bpf-next v3 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
2020-03-13 11:52 ` [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
0 siblings, 2 replies; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-13 11:52 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov
Cc: John Fastabend, Andrii Nakryiko, netdev, bpf
Currently, some samples are using ioctl for enabling perf_event and
attaching BPF programs to this event. However, the bpf_program__attach
of libbpf(using bpf_link) is much more intuitive than the previous
method using ioctl.
bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.
In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy.
To refactor samples with using this libbpf API, the bpf_load in the
samples were removed and migrated to libbbpf. Because read_trace_pipe
is used in bpf_load, multiple samples cannot be migrated to libbpf,
this function was moved to trace_helpers.
Changes in v2:
- check memory allocation is successful
- clean up allocated memory on error
Changes in v3:
- Improve pointer error check (IS_ERR())
- change to calloc for easier destroy of bpf_link
- remove perf_event fd list since bpf_link handles fd
- use newer bpf_object__{open/load} API instead of bpf_prog_load
- perf_event for _SC_NPROCESSORS_ONLN instead of _SC_NPROCESSORS_CONF
- sample specific chagnes...
Daniel T. Lee (2):
samples: bpf: move read_trace_pipe to trace_helpers
samples: bpf: refactor perf_event user program with libbpf bpf_link
samples/bpf/Makefile | 8 +-
samples/bpf/bpf_load.c | 20 ----
samples/bpf/bpf_load.h | 1 -
samples/bpf/sampleip_user.c | 100 +++++++++++++-------
samples/bpf/trace_event_user.c | 89 ++++++++++++-----
samples/bpf/tracex1_user.c | 1 +
samples/bpf/tracex5_user.c | 1 +
tools/testing/selftests/bpf/trace_helpers.c | 23 +++++
tools/testing/selftests/bpf/trace_helpers.h | 1 +
9 files changed, 159 insertions(+), 85 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH bpf-next v3 1/2] samples: bpf: move read_trace_pipe to trace_helpers
2020-03-13 11:52 [PATCH bpf-next v3 0/2] Refactor perf_event sample user program with libbpf bpf_link Daniel T. Lee
@ 2020-03-13 11:52 ` Daniel T. Lee
2020-03-13 11:52 ` [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
1 sibling, 0 replies; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-13 11:52 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov
Cc: John Fastabend, Andrii Nakryiko, netdev, bpf
To reduce the reliance of trace samples (trace*_user) on bpf_load,
move read_trace_pipe to trace_helpers. By moving this bpf_loader helper
elsewhere, trace functions can be easily migrated to libbbpf.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
---
samples/bpf/Makefile | 4 ++--
samples/bpf/bpf_load.c | 20 ------------------
samples/bpf/bpf_load.h | 1 -
samples/bpf/tracex1_user.c | 1 +
samples/bpf/tracex5_user.c | 1 +
tools/testing/selftests/bpf/trace_helpers.c | 23 +++++++++++++++++++++
tools/testing/selftests/bpf/trace_helpers.h | 1 +
7 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 79b0fee6943b..ff0061467dd3 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -64,11 +64,11 @@ fds_example-objs := fds_example.o
sockex1-objs := sockex1_user.o
sockex2-objs := sockex2_user.o
sockex3-objs := bpf_load.o sockex3_user.o
-tracex1-objs := bpf_load.o tracex1_user.o
+tracex1-objs := bpf_load.o tracex1_user.o $(TRACE_HELPERS)
tracex2-objs := bpf_load.o tracex2_user.o
tracex3-objs := bpf_load.o tracex3_user.o
tracex4-objs := bpf_load.o tracex4_user.o
-tracex5-objs := bpf_load.o tracex5_user.o
+tracex5-objs := bpf_load.o tracex5_user.o $(TRACE_HELPERS)
tracex6-objs := bpf_load.o tracex6_user.o
tracex7-objs := bpf_load.o tracex7_user.o
test_probe_write_user-objs := bpf_load.o test_probe_write_user_user.o
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 4574b1939e49..c5ad528f046e 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -665,23 +665,3 @@ int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map)
{
return do_load_bpf_file(path, fixup_map);
}
-
-void read_trace_pipe(void)
-{
- int trace_fd;
-
- trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
- if (trace_fd < 0)
- return;
-
- while (1) {
- static char buf[4096];
- ssize_t sz;
-
- sz = read(trace_fd, buf, sizeof(buf) - 1);
- if (sz > 0) {
- buf[sz] = 0;
- puts(buf);
- }
- }
-}
diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h
index 814894a12974..4fcd258c616f 100644
--- a/samples/bpf/bpf_load.h
+++ b/samples/bpf/bpf_load.h
@@ -53,6 +53,5 @@ extern int map_data_count;
int load_bpf_file(char *path);
int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map);
-void read_trace_pipe(void);
int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);
#endif
diff --git a/samples/bpf/tracex1_user.c b/samples/bpf/tracex1_user.c
index af8c20608ab5..55fddbd08702 100644
--- a/samples/bpf/tracex1_user.c
+++ b/samples/bpf/tracex1_user.c
@@ -4,6 +4,7 @@
#include <unistd.h>
#include <bpf/bpf.h>
#include "bpf_load.h"
+#include "trace_helpers.h"
int main(int ac, char **argv)
{
diff --git a/samples/bpf/tracex5_user.c b/samples/bpf/tracex5_user.c
index c4ab91c89494..c2317b39e0d2 100644
--- a/samples/bpf/tracex5_user.c
+++ b/samples/bpf/tracex5_user.c
@@ -8,6 +8,7 @@
#include <bpf/bpf.h>
#include "bpf_load.h"
#include <sys/resource.h>
+#include "trace_helpers.h"
/* install fake seccomp program to enable seccomp code path inside the kernel,
* so that our kprobe attached to seccomp_phase1() can be triggered
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 7f989b3e4e22..4d0e913bbb22 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -4,12 +4,15 @@
#include <string.h>
#include <assert.h>
#include <errno.h>
+#include <fcntl.h>
#include <poll.h>
#include <unistd.h>
#include <linux/perf_event.h>
#include <sys/mman.h>
#include "trace_helpers.h"
+#define DEBUGFS "/sys/kernel/debug/tracing/"
+
#define MAX_SYMS 300000
static struct ksym syms[MAX_SYMS];
static int sym_cnt;
@@ -86,3 +89,23 @@ long ksym_get_addr(const char *name)
return 0;
}
+
+void read_trace_pipe(void)
+{
+ int trace_fd;
+
+ trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
+ if (trace_fd < 0)
+ return;
+
+ while (1) {
+ static char buf[4096];
+ ssize_t sz;
+
+ sz = read(trace_fd, buf, sizeof(buf) - 1);
+ if (sz > 0) {
+ buf[sz] = 0;
+ puts(buf);
+ }
+ }
+}
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 0383c9b8adc1..25ef597dd03f 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -12,5 +12,6 @@ struct ksym {
int load_kallsyms(void);
struct ksym *ksym_search(long key);
long ksym_get_addr(const char *name);
+void read_trace_pipe(void);
#endif
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-13 11:52 [PATCH bpf-next v3 0/2] Refactor perf_event sample user program with libbpf bpf_link Daniel T. Lee
2020-03-13 11:52 ` [PATCH bpf-next v3 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
@ 2020-03-13 11:52 ` Daniel T. Lee
2020-03-13 18:48 ` Andrii Nakryiko
1 sibling, 1 reply; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-13 11:52 UTC (permalink / raw)
To: Daniel Borkmann, Alexei Starovoitov
Cc: John Fastabend, Andrii Nakryiko, netdev, bpf
The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
than the previous method using ioctl.
bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.
In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy. Also, bpf_link__destroy manages the close() of
perf_event fd.
This commit refactors samples that attach the bpf program to perf_event
by using libbbpf instead of ioctl. Also the bpf_load in the samples were
removed and migrated to use libbbpf API.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
---
Changes in v2:
- check memory allocation is successful
- clean up allocated memory on error
Changes in v3:
- Improve pointer error check (IS_ERR())
- change to calloc for easier destroy of bpf_link
- remove perf_event fd list since bpf_link handles fd
- use newer bpf_object__{open/load} API instead of bpf_prog_load
- perf_event for _SC_NPROCESSORS_ONLN instead of _SC_NPROCESSORS_CONF
- find program with name explicitly instead of bpf_program__next
- unconditional bpf_link__destroy() on cleanup
- return error code on int_exit
samples/bpf/Makefile | 4 +-
samples/bpf/sampleip_user.c | 100 ++++++++++++++++++++++-----------
samples/bpf/trace_event_user.c | 89 ++++++++++++++++++++---------
3 files changed, 131 insertions(+), 62 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index ff0061467dd3..424f6fe7ce38 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -88,8 +88,8 @@ xdp2-objs := xdp1_user.o
xdp_router_ipv4-objs := xdp_router_ipv4_user.o
test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
test_current_task_under_cgroup_user.o
-trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
-sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
+trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
+sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
index b0f115f938bc..05eca7b00e22 100644
--- a/samples/bpf/sampleip_user.c
+++ b/samples/bpf/sampleip_user.c
@@ -10,21 +10,23 @@
#include <errno.h>
#include <signal.h>
#include <string.h>
-#include <assert.h>
#include <linux/perf_event.h>
#include <linux/ptrace.h>
#include <linux/bpf.h>
-#include <sys/ioctl.h>
+#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
+#define __must_check
+#include <linux/err.h>
+
#define DEFAULT_FREQ 99
#define DEFAULT_SECS 5
#define MAX_IPS 8192
#define PAGE_OFFSET 0xffff880000000000
+static int map_fd;
static int nr_cpus;
static void usage(void)
@@ -34,9 +36,10 @@ static void usage(void)
printf(" duration # sampling duration (seconds), default 5\n");
}
-static int sampling_start(int *pmu_fd, int freq)
+static int sampling_start(int freq, struct bpf_program *prog,
+ struct bpf_link *links[])
{
- int i;
+ int i, pmu_fd;
struct perf_event_attr pe_sample_attr = {
.type = PERF_TYPE_SOFTWARE,
@@ -47,26 +50,29 @@ static int sampling_start(int *pmu_fd, int freq)
};
for (i = 0; i < nr_cpus; i++) {
- pmu_fd[i] = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
+ pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
-1 /* group_fd */, 0 /* flags */);
- if (pmu_fd[i] < 0) {
+ if (pmu_fd < 0) {
fprintf(stderr, "ERROR: Initializing perf sampling\n");
return 1;
}
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF,
- prog_fd[0]) == 0);
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
+ links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
+ if (IS_ERR(links[i])) {
+ fprintf(stderr, "ERROR: Attach perf event\n");
+ close(pmu_fd);
+ return 1;
+ }
}
return 0;
}
-static void sampling_end(int *pmu_fd)
+static void sampling_end(struct bpf_link *links[])
{
int i;
for (i = 0; i < nr_cpus; i++)
- close(pmu_fd[i]);
+ bpf_link__destroy(links[i]);
}
struct ipcount {
@@ -128,14 +134,17 @@ static void print_ip_map(int fd)
static void int_exit(int sig)
{
printf("\n");
- print_ip_map(map_fd[0]);
+ print_ip_map(map_fd);
exit(0);
}
int main(int argc, char **argv)
{
+ int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 0;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ struct bpf_link **links;
char filename[256];
- int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
/* process arguments */
while ((opt = getopt(argc, argv, "F:h")) != -1) {
@@ -163,38 +172,61 @@ int main(int argc, char **argv)
}
/* create perf FDs for each CPU */
- nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
- pmu_fd = malloc(nr_cpus * sizeof(int));
- if (pmu_fd == NULL) {
- fprintf(stderr, "ERROR: malloc of pmu_fd\n");
- return 1;
+ nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+ links = calloc(nr_cpus, sizeof(struct bpf_link *));
+ if (!links) {
+ fprintf(stderr, "ERROR: malloc of links\n");
+ error = 1;
+ goto cleanup;
}
- /* load BPF program */
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
- if (load_bpf_file(filename)) {
- fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
- errno);
- if (strcmp(bpf_log_buf, "") == 0)
- fprintf(stderr, "Try: ulimit -l unlimited\n");
- else
- fprintf(stderr, "%s", bpf_log_buf);
- return 1;
+ obj = bpf_object__open_file(filename, NULL);
+ if (IS_ERR(obj)) {
+ fprintf(stderr, "ERROR: opening BPF object file failed\n");
+ error = 1;
+ goto cleanup;
+ }
+
+ prog = bpf_object__find_program_by_name(obj, "do_sample");
+ if (!prog) {
+ fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
+ error = 1;
+ goto cleanup;
}
+
+ /* load BPF program */
+ if (bpf_object__load(obj)) {
+ fprintf(stderr, "ERROR: loading BPF object file failed\n");
+ error = 1;
+ goto cleanup;
+ }
+
+ map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
+ if (map_fd < 0) {
+ fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+ error = 1;
+ goto cleanup;
+ }
+
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
/* do sampling */
printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
freq, secs);
- if (sampling_start(pmu_fd, freq) != 0)
- return 1;
+ if (sampling_start(freq, prog, links) != 0) {
+ error = 1;
+ goto cleanup;
+ }
sleep(secs);
- sampling_end(pmu_fd);
- free(pmu_fd);
+cleanup:
+ sampling_end(links);
/* output sample counts */
- print_ip_map(map_fd[0]);
+ if (!error)
+ print_ip_map(map_fd);
- return 0;
+ free(links);
+ return error;
}
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
index 356171bc392b..5f64ff524cc3 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -6,22 +6,24 @@
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
-#include <fcntl.h>
-#include <poll.h>
-#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <signal.h>
-#include <assert.h>
#include <errno.h>
#include <sys/resource.h>
+#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
+#define __must_check
+#include <linux/err.h>
+
#define SAMPLE_FREQ 50
+/* counts, stackmap */
+static int map_fd[2];
+struct bpf_program *prog;
static bool sys_read_seen, sys_write_seen;
static void print_ksym(__u64 addr)
@@ -136,23 +138,34 @@ static inline int generate_load(void)
static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
- int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
- int *pmu_fd = malloc(nr_cpus * sizeof(int));
- int i, error = 0;
+ int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+ struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
+ int i, pmu_fd, error = 0;
+
+ if (!links) {
+ printf("malloc of links failed\n");
+ error = 1;
+ goto err;
+ }
/* system wide perf event, no need to inherit */
attr->inherit = 0;
/* open perf_event on all cpus */
for (i = 0; i < nr_cpus; i++) {
- pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
- if (pmu_fd[i] < 0) {
+ pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
+ if (pmu_fd < 0) {
printf("sys_perf_event_open failed\n");
error = 1;
goto all_cpu_err;
}
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
+ links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
+ if (IS_ERR(links[i])) {
+ printf("bpf_program__attach_perf_event failed\n");
+ close(pmu_fd);
+ error = 1;
+ goto all_cpu_err;
+ }
}
if (generate_load() < 0) {
@@ -161,18 +174,18 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
}
print_stacks();
all_cpu_err:
- for (i--; i >= 0; i--) {
- ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
- close(pmu_fd[i]);
- }
- free(pmu_fd);
+ for (i--; i >= 0; i--)
+ bpf_link__destroy(links[i]);
+err:
+ free(links);
if (error)
- int_exit(0);
+ int_exit(error);
}
static void test_perf_event_task(struct perf_event_attr *attr)
{
int pmu_fd, error = 0;
+ struct bpf_link *link;
/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
* Enabling inherit will cause bpf_perf_prog_read_time helper failure.
@@ -185,8 +198,12 @@ static void test_perf_event_task(struct perf_event_attr *attr)
printf("sys_perf_event_open failed\n");
int_exit(0);
}
- assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
- assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
+ link = bpf_program__attach_perf_event(prog, pmu_fd);
+ if (IS_ERR(link)) {
+ printf("bpf_program__attach_perf_event failed\n");
+ close(pmu_fd);
+ int_exit(0);
+ }
if (generate_load() < 0) {
error = 1;
@@ -194,10 +211,9 @@ static void test_perf_event_task(struct perf_event_attr *attr)
}
print_stacks();
err:
- ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
- close(pmu_fd);
+ bpf_link__destroy(link);
if (error)
- int_exit(0);
+ int_exit(error);
}
static void test_bpf_perf_event(void)
@@ -282,6 +298,7 @@ static void test_bpf_perf_event(void)
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ struct bpf_object *obj;
char filename[256];
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
@@ -295,9 +312,29 @@ int main(int argc, char **argv)
return 1;
}
- if (load_bpf_file(filename)) {
- printf("%s", bpf_log_buf);
- return 2;
+ obj = bpf_object__open_file(filename, NULL);
+ if (IS_ERR(obj)) {
+ printf("opening BPF object file failed\n");
+ return 1;
+ }
+
+ prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+ if (!prog) {
+ printf("finding a prog in obj file failed\n");
+ return 1;
+ }
+
+ /* load BPF program */
+ if (bpf_object__load(obj)) {
+ printf("loading BPF object file failed\n");
+ return 1;
+ }
+
+ 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) {
+ printf("finding a counts/stackmap map in obj file failed\n");
+ return 1;
}
if (fork() == 0) {
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-13 11:52 ` [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
@ 2020-03-13 18:48 ` Andrii Nakryiko
2020-03-14 1:45 ` Daniel T. Lee
0 siblings, 1 reply; 6+ messages in thread
From: Andrii Nakryiko @ 2020-03-13 18:48 UTC (permalink / raw)
To: Daniel T. Lee
Cc: Daniel Borkmann, Alexei Starovoitov, John Fastabend, Networking, bpf
On Fri, Mar 13, 2020 at 4:52 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
>
> The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
> than the previous method using ioctl.
>
> bpf_program__attach_perf_event manages the enable of perf_event and
> attach of BPF programs to it, so there's no neeed to do this
> directly with ioctl.
>
> In addition, bpf_link provides consistency in the use of API because it
> allows disable (detach, destroy) for multiple events to be treated as
> one bpf_link__destroy. Also, bpf_link__destroy manages the close() of
> perf_event fd.
>
> This commit refactors samples that attach the bpf program to perf_event
> by using libbbpf instead of ioctl. Also the bpf_load in the samples were
> removed and migrated to use libbbpf API.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> ---
> Changes in v2:
> - check memory allocation is successful
> - clean up allocated memory on error
>
> Changes in v3:
> - Improve pointer error check (IS_ERR())
> - change to calloc for easier destroy of bpf_link
> - remove perf_event fd list since bpf_link handles fd
> - use newer bpf_object__{open/load} API instead of bpf_prog_load
> - perf_event for _SC_NPROCESSORS_ONLN instead of _SC_NPROCESSORS_CONF
> - find program with name explicitly instead of bpf_program__next
> - unconditional bpf_link__destroy() on cleanup
> - return error code on int_exit
>
> samples/bpf/Makefile | 4 +-
> samples/bpf/sampleip_user.c | 100 ++++++++++++++++++++++-----------
> samples/bpf/trace_event_user.c | 89 ++++++++++++++++++++---------
> 3 files changed, 131 insertions(+), 62 deletions(-)
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index ff0061467dd3..424f6fe7ce38 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -88,8 +88,8 @@ xdp2-objs := xdp1_user.o
> xdp_router_ipv4-objs := xdp_router_ipv4_user.o
> test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
> test_current_task_under_cgroup_user.o
> -trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
> -sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
> +trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
> +sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
> tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
> lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
> xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
> diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
> index b0f115f938bc..05eca7b00e22 100644
> --- a/samples/bpf/sampleip_user.c
> +++ b/samples/bpf/sampleip_user.c
> @@ -10,21 +10,23 @@
> #include <errno.h>
> #include <signal.h>
> #include <string.h>
> -#include <assert.h>
> #include <linux/perf_event.h>
> #include <linux/ptrace.h>
> #include <linux/bpf.h>
> -#include <sys/ioctl.h>
> +#include <bpf/bpf.h>
> #include <bpf/libbpf.h>
> -#include "bpf_load.h"
> #include "perf-sys.h"
> #include "trace_helpers.h"
>
> +#define __must_check
> +#include <linux/err.h>
> +
> #define DEFAULT_FREQ 99
> #define DEFAULT_SECS 5
> #define MAX_IPS 8192
> #define PAGE_OFFSET 0xffff880000000000
>
> +static int map_fd;
> static int nr_cpus;
>
> static void usage(void)
> @@ -34,9 +36,10 @@ static void usage(void)
> printf(" duration # sampling duration (seconds), default 5\n");
> }
>
> -static int sampling_start(int *pmu_fd, int freq)
> +static int sampling_start(int freq, struct bpf_program *prog,
> + struct bpf_link *links[])
> {
> - int i;
> + int i, pmu_fd;
>
> struct perf_event_attr pe_sample_attr = {
> .type = PERF_TYPE_SOFTWARE,
> @@ -47,26 +50,29 @@ static int sampling_start(int *pmu_fd, int freq)
> };
>
> for (i = 0; i < nr_cpus; i++) {
> - pmu_fd[i] = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
> + pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
> -1 /* group_fd */, 0 /* flags */);
> - if (pmu_fd[i] < 0) {
> + if (pmu_fd < 0) {
> fprintf(stderr, "ERROR: Initializing perf sampling\n");
> return 1;
> }
> - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF,
> - prog_fd[0]) == 0);
> - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
> + links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
> + if (IS_ERR(links[i])) {
links[i] = NULL;
> + fprintf(stderr, "ERROR: Attach perf event\n");
> + close(pmu_fd);
> + return 1;
> + }
> }
>
> return 0;
> }
>
> -static void sampling_end(int *pmu_fd)
> +static void sampling_end(struct bpf_link *links[])
> {
> int i;
>
> for (i = 0; i < nr_cpus; i++)
> - close(pmu_fd[i]);
> + bpf_link__destroy(links[i]);
> }
>
> struct ipcount {
> @@ -128,14 +134,17 @@ static void print_ip_map(int fd)
> static void int_exit(int sig)
> {
> printf("\n");
> - print_ip_map(map_fd[0]);
> + print_ip_map(map_fd);
> exit(0);
> }
>
> int main(int argc, char **argv)
> {
> + int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 0;
> + struct bpf_program *prog;
> + struct bpf_object *obj;
initialize to NULL here
> + struct bpf_link **links;
> char filename[256];
> - int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
>
> /* process arguments */
> while ((opt = getopt(argc, argv, "F:h")) != -1) {
> @@ -163,38 +172,61 @@ int main(int argc, char **argv)
> }
>
> /* create perf FDs for each CPU */
> - nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> - pmu_fd = malloc(nr_cpus * sizeof(int));
> - if (pmu_fd == NULL) {
> - fprintf(stderr, "ERROR: malloc of pmu_fd\n");
> - return 1;
> + nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> + links = calloc(nr_cpus, sizeof(struct bpf_link *));
> + if (!links) {
> + fprintf(stderr, "ERROR: malloc of links\n");
> + error = 1;
> + goto cleanup;
> }
>
> - /* load BPF program */
> snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> - if (load_bpf_file(filename)) {
> - fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
> - errno);
> - if (strcmp(bpf_log_buf, "") == 0)
> - fprintf(stderr, "Try: ulimit -l unlimited\n");
> - else
> - fprintf(stderr, "%s", bpf_log_buf);
> - return 1;
> + obj = bpf_object__open_file(filename, NULL);
> + if (IS_ERR(obj)) {
obj = NULL;
> + fprintf(stderr, "ERROR: opening BPF object file failed\n");
> + error = 1;
> + goto cleanup;
> + }
> +
> + prog = bpf_object__find_program_by_name(obj, "do_sample");
> + if (!prog) {
> + fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
> + error = 1;
> + goto cleanup;
> }
> +
> + /* load BPF program */
> + if (bpf_object__load(obj)) {
> + fprintf(stderr, "ERROR: loading BPF object file failed\n");
> + error = 1;
> + goto cleanup;
> + }
> +
> + map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
> + if (map_fd < 0) {
> + fprintf(stderr, "ERROR: finding a map in obj file failed\n");
> + error = 1;
> + goto cleanup;
> + }
> +
> signal(SIGINT, int_exit);
> signal(SIGTERM, int_exit);
>
> /* do sampling */
> printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
> freq, secs);
> - if (sampling_start(pmu_fd, freq) != 0)
> - return 1;
> + if (sampling_start(freq, prog, links) != 0) {
> + error = 1;
> + goto cleanup;
> + }
> sleep(secs);
> - sampling_end(pmu_fd);
> - free(pmu_fd);
>
> +cleanup:
> + sampling_end(links);
bpf_object__destroy(obj)
> /* output sample counts */
> - print_ip_map(map_fd[0]);
> + if (!error)
> + print_ip_map(map_fd);
>
> - return 0;
> + free(links);
> + return error;
> }
> diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
> index 356171bc392b..5f64ff524cc3 100644
> --- a/samples/bpf/trace_event_user.c
> +++ b/samples/bpf/trace_event_user.c
> @@ -6,22 +6,24 @@
> #include <stdlib.h>
> #include <stdbool.h>
> #include <string.h>
> -#include <fcntl.h>
> -#include <poll.h>
> -#include <sys/ioctl.h>
> #include <linux/perf_event.h>
> #include <linux/bpf.h>
> #include <signal.h>
> -#include <assert.h>
> #include <errno.h>
> #include <sys/resource.h>
> +#include <bpf/bpf.h>
> #include <bpf/libbpf.h>
> -#include "bpf_load.h"
> #include "perf-sys.h"
> #include "trace_helpers.h"
>
> +#define __must_check
> +#include <linux/err.h>
> +
> #define SAMPLE_FREQ 50
>
> +/* counts, stackmap */
> +static int map_fd[2];
> +struct bpf_program *prog;
> static bool sys_read_seen, sys_write_seen;
>
> static void print_ksym(__u64 addr)
> @@ -136,23 +138,34 @@ static inline int generate_load(void)
>
> static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> {
> - int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> - int *pmu_fd = malloc(nr_cpus * sizeof(int));
> - int i, error = 0;
> + int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> + struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
> + int i, pmu_fd, error = 0;
> +
> + if (!links) {
> + printf("malloc of links failed\n");
> + error = 1;
> + goto err;
> + }
>
> /* system wide perf event, no need to inherit */
> attr->inherit = 0;
>
> /* open perf_event on all cpus */
> for (i = 0; i < nr_cpus; i++) {
> - pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
> - if (pmu_fd[i] < 0) {
> + pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
> + if (pmu_fd < 0) {
> printf("sys_perf_event_open failed\n");
> error = 1;
> goto all_cpu_err;
> }
> - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
> + links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
> + if (IS_ERR(links[i])) {
> + printf("bpf_program__attach_perf_event failed\n");
> + close(pmu_fd);
> + error = 1;
> + goto all_cpu_err;
> + }
> }
>
> if (generate_load() < 0) {
> @@ -161,18 +174,18 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> }
> print_stacks();
> all_cpu_err:
> - for (i--; i >= 0; i--) {
> - ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
> - close(pmu_fd[i]);
> - }
> - free(pmu_fd);
> + for (i--; i >= 0; i--)
> + bpf_link__destroy(links[i]);
> +err:
> + free(links);
> if (error)
> - int_exit(0);
> + int_exit(error);
> }
>
> static void test_perf_event_task(struct perf_event_attr *attr)
> {
> int pmu_fd, error = 0;
> + struct bpf_link *link;
>
> /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
> * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
> @@ -185,8 +198,12 @@ static void test_perf_event_task(struct perf_event_attr *attr)
> printf("sys_perf_event_open failed\n");
> int_exit(0);
> }
> - assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> - assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
> + link = bpf_program__attach_perf_event(prog, pmu_fd);
> + if (IS_ERR(link)) {
> + printf("bpf_program__attach_perf_event failed\n");
> + close(pmu_fd);
> + int_exit(0);
> + }
>
> if (generate_load() < 0) {
> error = 1;
> @@ -194,10 +211,9 @@ static void test_perf_event_task(struct perf_event_attr *attr)
> }
> print_stacks();
> err:
> - ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
> - close(pmu_fd);
> + bpf_link__destroy(link);
> if (error)
> - int_exit(0);
> + int_exit(error);
> }
>
> static void test_bpf_perf_event(void)
> @@ -282,6 +298,7 @@ static void test_bpf_perf_event(void)
> int main(int argc, char **argv)
> {
> struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
> + struct bpf_object *obj;
> char filename[256];
>
> snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> @@ -295,9 +312,29 @@ int main(int argc, char **argv)
> return 1;
> }
>
> - if (load_bpf_file(filename)) {
> - printf("%s", bpf_log_buf);
> - return 2;
> + obj = bpf_object__open_file(filename, NULL);
> + if (IS_ERR(obj)) {
> + printf("opening BPF object file failed\n");
> + return 1;
> + }
> +
> + prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
> + if (!prog) {
> + printf("finding a prog in obj file failed\n");
bpf_object__close(obj);
> + return 1;
> + }
> +
> + /* load BPF program */
> + if (bpf_object__load(obj)) {
close bpf_object (better do goto clean approach, of course)
> + printf("loading BPF object file failed\n");
> + return 1;
> + }
> +
> + 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) {
> + printf("finding a counts/stackmap map in obj file failed\n");
> + return 1;
> }
>
> if (fork() == 0) {
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-13 18:48 ` Andrii Nakryiko
@ 2020-03-14 1:45 ` Daniel T. Lee
2020-03-14 1:48 ` Andrii Nakryiko
0 siblings, 1 reply; 6+ messages in thread
From: Daniel T. Lee @ 2020-03-14 1:45 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Daniel Borkmann, Alexei Starovoitov, John Fastabend, Networking, bpf
On Sat, Mar 14, 2020 at 3:48 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Fri, Mar 13, 2020 at 4:52 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
> >
> > The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
> > than the previous method using ioctl.
> >
> > bpf_program__attach_perf_event manages the enable of perf_event and
> > attach of BPF programs to it, so there's no neeed to do this
> > directly with ioctl.
> >
> > In addition, bpf_link provides consistency in the use of API because it
> > allows disable (detach, destroy) for multiple events to be treated as
> > one bpf_link__destroy. Also, bpf_link__destroy manages the close() of
> > perf_event fd.
> >
> > This commit refactors samples that attach the bpf program to perf_event
> > by using libbbpf instead of ioctl. Also the bpf_load in the samples were
> > removed and migrated to use libbbpf API.
> >
> > Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> > ---
> > Changes in v2:
> > - check memory allocation is successful
> > - clean up allocated memory on error
> >
> > Changes in v3:
> > - Improve pointer error check (IS_ERR())
> > - change to calloc for easier destroy of bpf_link
> > - remove perf_event fd list since bpf_link handles fd
> > - use newer bpf_object__{open/load} API instead of bpf_prog_load
> > - perf_event for _SC_NPROCESSORS_ONLN instead of _SC_NPROCESSORS_CONF
> > - find program with name explicitly instead of bpf_program__next
> > - unconditional bpf_link__destroy() on cleanup
> > - return error code on int_exit
> >
> > samples/bpf/Makefile | 4 +-
> > samples/bpf/sampleip_user.c | 100 ++++++++++++++++++++++-----------
> > samples/bpf/trace_event_user.c | 89 ++++++++++++++++++++---------
> > 3 files changed, 131 insertions(+), 62 deletions(-)
> >
> > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> > index ff0061467dd3..424f6fe7ce38 100644
> > --- a/samples/bpf/Makefile
> > +++ b/samples/bpf/Makefile
> > @@ -88,8 +88,8 @@ xdp2-objs := xdp1_user.o
> > xdp_router_ipv4-objs := xdp_router_ipv4_user.o
> > test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
> > test_current_task_under_cgroup_user.o
> > -trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
> > -sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
> > +trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
> > +sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
> > tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
> > lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
> > xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
> > diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
> > index b0f115f938bc..05eca7b00e22 100644
> > --- a/samples/bpf/sampleip_user.c
> > +++ b/samples/bpf/sampleip_user.c
> > @@ -10,21 +10,23 @@
> > #include <errno.h>
> > #include <signal.h>
> > #include <string.h>
> > -#include <assert.h>
> > #include <linux/perf_event.h>
> > #include <linux/ptrace.h>
> > #include <linux/bpf.h>
> > -#include <sys/ioctl.h>
> > +#include <bpf/bpf.h>
> > #include <bpf/libbpf.h>
> > -#include "bpf_load.h"
> > #include "perf-sys.h"
> > #include "trace_helpers.h"
> >
> > +#define __must_check
> > +#include <linux/err.h>
> > +
> > #define DEFAULT_FREQ 99
> > #define DEFAULT_SECS 5
> > #define MAX_IPS 8192
> > #define PAGE_OFFSET 0xffff880000000000
> >
> > +static int map_fd;
> > static int nr_cpus;
> >
> > static void usage(void)
> > @@ -34,9 +36,10 @@ static void usage(void)
> > printf(" duration # sampling duration (seconds), default 5\n");
> > }
> >
> > -static int sampling_start(int *pmu_fd, int freq)
> > +static int sampling_start(int freq, struct bpf_program *prog,
> > + struct bpf_link *links[])
> > {
> > - int i;
> > + int i, pmu_fd;
> >
> > struct perf_event_attr pe_sample_attr = {
> > .type = PERF_TYPE_SOFTWARE,
> > @@ -47,26 +50,29 @@ static int sampling_start(int *pmu_fd, int freq)
> > };
> >
> > for (i = 0; i < nr_cpus; i++) {
> > - pmu_fd[i] = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
> > + pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
> > -1 /* group_fd */, 0 /* flags */);
> > - if (pmu_fd[i] < 0) {
> > + if (pmu_fd < 0) {
> > fprintf(stderr, "ERROR: Initializing perf sampling\n");
> > return 1;
> > }
> > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF,
> > - prog_fd[0]) == 0);
> > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
> > + links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
> > + if (IS_ERR(links[i])) {
>
> links[i] = NULL;
>
Since bpf_program__attach_perf_event will return err code such
as ERR_PTR(-EINVAL), so it is natural to reset the pointer to NULL!
Thank you for the heads up!
> > + fprintf(stderr, "ERROR: Attach perf event\n");
> > + close(pmu_fd);
> > + return 1;
> > + }
> > }
> >
> > return 0;
> > }
> >
> > -static void sampling_end(int *pmu_fd)
> > +static void sampling_end(struct bpf_link *links[])
> > {
> > int i;
> >
> > for (i = 0; i < nr_cpus; i++)
> > - close(pmu_fd[i]);
> > + bpf_link__destroy(links[i]);
> > }
> >
> > struct ipcount {
> > @@ -128,14 +134,17 @@ static void print_ip_map(int fd)
> > static void int_exit(int sig)
> > {
> > printf("\n");
> > - print_ip_map(map_fd[0]);
> > + print_ip_map(map_fd);
> > exit(0);
> > }
> >
> > int main(int argc, char **argv)
> > {
> > + int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 0;
> > + struct bpf_program *prog;
> > + struct bpf_object *obj;
>
> initialize to NULL here
>
I'll apply this at next version patch.
> > + struct bpf_link **links;
> > char filename[256];
> > - int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
> >
> > /* process arguments */
> > while ((opt = getopt(argc, argv, "F:h")) != -1) {
> > @@ -163,38 +172,61 @@ int main(int argc, char **argv)
> > }
> >
> > /* create perf FDs for each CPU */
> > - nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > - pmu_fd = malloc(nr_cpus * sizeof(int));
> > - if (pmu_fd == NULL) {
> > - fprintf(stderr, "ERROR: malloc of pmu_fd\n");
> > - return 1;
> > + nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> > + links = calloc(nr_cpus, sizeof(struct bpf_link *));
> > + if (!links) {
> > + fprintf(stderr, "ERROR: malloc of links\n");
> > + error = 1;
> > + goto cleanup;
> > }
> >
> > - /* load BPF program */
> > snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> > - if (load_bpf_file(filename)) {
> > - fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
> > - errno);
> > - if (strcmp(bpf_log_buf, "") == 0)
> > - fprintf(stderr, "Try: ulimit -l unlimited\n");
> > - else
> > - fprintf(stderr, "%s", bpf_log_buf);
> > - return 1;
> > + obj = bpf_object__open_file(filename, NULL);
> > + if (IS_ERR(obj)) {
>
> obj = NULL;
>
Also again, bpf_object__open_file will return err code of pointer,
and the pointer needs to be set to NULL for bpf_object__close.
> > + fprintf(stderr, "ERROR: opening BPF object file failed\n");
> > + error = 1;
> > + goto cleanup;
> > + }
> > +
> > + prog = bpf_object__find_program_by_name(obj, "do_sample");
> > + if (!prog) {
> > + fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
> > + error = 1;
> > + goto cleanup;
> > }
> > +
> > + /* load BPF program */
> > + if (bpf_object__load(obj)) {
> > + fprintf(stderr, "ERROR: loading BPF object file failed\n");
> > + error = 1;
> > + goto cleanup;
> > + }
> > +
> > + map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
> > + if (map_fd < 0) {
> > + fprintf(stderr, "ERROR: finding a map in obj file failed\n");
> > + error = 1;
> > + goto cleanup;
> > + }
> > +
> > signal(SIGINT, int_exit);
> > signal(SIGTERM, int_exit);
> >
> > /* do sampling */
> > printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
> > freq, secs);
> > - if (sampling_start(pmu_fd, freq) != 0)
> > - return 1;
> > + if (sampling_start(freq, prog, links) != 0) {
> > + error = 1;
> > + goto cleanup;
> > + }
> > sleep(secs);
> > - sampling_end(pmu_fd);
> > - free(pmu_fd);
> >
> > +cleanup:
> > + sampling_end(links);
>
> bpf_object__destroy(obj)
>
Sorry, but I might not following you, but is there bpf_object__destroy
exist in libbpf? I guess you're talking about bpf_object__close, right?
> > /* output sample counts */
> > - print_ip_map(map_fd[0]);
> > + if (!error)
> > + print_ip_map(map_fd);
> >
> > - return 0;
> > + free(links);
> > + return error;
> > }
> > diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
> > index 356171bc392b..5f64ff524cc3 100644
> > --- a/samples/bpf/trace_event_user.c
> > +++ b/samples/bpf/trace_event_user.c
> > @@ -6,22 +6,24 @@
> > #include <stdlib.h>
> > #include <stdbool.h>
> > #include <string.h>
> > -#include <fcntl.h>
> > -#include <poll.h>
> > -#include <sys/ioctl.h>
> > #include <linux/perf_event.h>
> > #include <linux/bpf.h>
> > #include <signal.h>
> > -#include <assert.h>
> > #include <errno.h>
> > #include <sys/resource.h>
> > +#include <bpf/bpf.h>
> > #include <bpf/libbpf.h>
> > -#include "bpf_load.h"
> > #include "perf-sys.h"
> > #include "trace_helpers.h"
> >
> > +#define __must_check
> > +#include <linux/err.h>
> > +
> > #define SAMPLE_FREQ 50
> >
> > +/* counts, stackmap */
> > +static int map_fd[2];
> > +struct bpf_program *prog;
> > static bool sys_read_seen, sys_write_seen;
> >
> > static void print_ksym(__u64 addr)
> > @@ -136,23 +138,34 @@ static inline int generate_load(void)
> >
> > static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > {
> > - int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > - int *pmu_fd = malloc(nr_cpus * sizeof(int));
> > - int i, error = 0;
> > + int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> > + struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
> > + int i, pmu_fd, error = 0;
> > +
> > + if (!links) {
> > + printf("malloc of links failed\n");
> > + error = 1;
> > + goto err;
> > + }
> >
> > /* system wide perf event, no need to inherit */
> > attr->inherit = 0;
> >
> > /* open perf_event on all cpus */
> > for (i = 0; i < nr_cpus; i++) {
> > - pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
> > - if (pmu_fd[i] < 0) {
> > + pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
> > + if (pmu_fd < 0) {
> > printf("sys_perf_event_open failed\n");
> > error = 1;
> > goto all_cpu_err;
> > }
> > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
> > + links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
> > + if (IS_ERR(links[i])) {
> > + printf("bpf_program__attach_perf_event failed\n");
> > + close(pmu_fd);
> > + error = 1;
> > + goto all_cpu_err;
> > + }
> > }
> >
> > if (generate_load() < 0) {
> > @@ -161,18 +174,18 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > }
> > print_stacks();
> > all_cpu_err:
> > - for (i--; i >= 0; i--) {
> > - ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
> > - close(pmu_fd[i]);
> > - }
> > - free(pmu_fd);
> > + for (i--; i >= 0; i--)
> > + bpf_link__destroy(links[i]);
> > +err:
> > + free(links);
> > if (error)
> > - int_exit(0);
> > + int_exit(error);
> > }
> >
> > static void test_perf_event_task(struct perf_event_attr *attr)
> > {
> > int pmu_fd, error = 0;
> > + struct bpf_link *link;
> >
> > /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
> > * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
> > @@ -185,8 +198,12 @@ static void test_perf_event_task(struct perf_event_attr *attr)
> > printf("sys_perf_event_open failed\n");
> > int_exit(0);
> > }
> > - assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> > - assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
> > + link = bpf_program__attach_perf_event(prog, pmu_fd);
> > + if (IS_ERR(link)) {
> > + printf("bpf_program__attach_perf_event failed\n");
> > + close(pmu_fd);
> > + int_exit(0);
> > + }
> >
> > if (generate_load() < 0) {
> > error = 1;
> > @@ -194,10 +211,9 @@ static void test_perf_event_task(struct perf_event_attr *attr)
> > }
> > print_stacks();
> > err:
> > - ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
> > - close(pmu_fd);
> > + bpf_link__destroy(link);
> > if (error)
> > - int_exit(0);
> > + int_exit(error);
> > }
> >
> > static void test_bpf_perf_event(void)
> > @@ -282,6 +298,7 @@ static void test_bpf_perf_event(void)
> > int main(int argc, char **argv)
> > {
> > struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
> > + struct bpf_object *obj;
> > char filename[256];
> >
> > snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> > @@ -295,9 +312,29 @@ int main(int argc, char **argv)
> > return 1;
> > }
> >
> > - if (load_bpf_file(filename)) {
> > - printf("%s", bpf_log_buf);
> > - return 2;
> > + obj = bpf_object__open_file(filename, NULL);
> > + if (IS_ERR(obj)) {
> > + printf("opening BPF object file failed\n");
> > + return 1;
> > + }
> > +
> > + prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
> > + if (!prog) {
> > + printf("finding a prog in obj file failed\n");
>
>
> bpf_object__close(obj);
>
Also, I'll apply this at next version patch.
> > + return 1;
> > + }
> > +
> > + /* load BPF program */
> > + if (bpf_object__load(obj)) {
>
> close bpf_object (better do goto clean approach, of course)
>
I will modify this with goto cleanup approach.
> > + printf("loading BPF object file failed\n");
> > + return 1;
> > + }
> > +
> > + 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) {
> > + printf("finding a counts/stackmap map in obj file failed\n");
> > + return 1;
> > }
> >
> > if (fork() == 0) {
> > --
> > 2.25.1
> >
Thank you for your time and effort for the review :)
Best,
Daniel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link
2020-03-14 1:45 ` Daniel T. Lee
@ 2020-03-14 1:48 ` Andrii Nakryiko
0 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2020-03-14 1:48 UTC (permalink / raw)
To: Daniel T. Lee
Cc: Daniel Borkmann, Alexei Starovoitov, John Fastabend, Networking, bpf
On Fri, Mar 13, 2020 at 6:46 PM Daniel T. Lee <danieltimlee@gmail.com> wrote:
>
> On Sat, Mar 14, 2020 at 3:48 AM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > On Fri, Mar 13, 2020 at 4:52 AM Daniel T. Lee <danieltimlee@gmail.com> wrote:
> > >
> > > The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
> > > than the previous method using ioctl.
> > >
> > > bpf_program__attach_perf_event manages the enable of perf_event and
> > > attach of BPF programs to it, so there's no neeed to do this
> > > directly with ioctl.
> > >
> > > In addition, bpf_link provides consistency in the use of API because it
> > > allows disable (detach, destroy) for multiple events to be treated as
> > > one bpf_link__destroy. Also, bpf_link__destroy manages the close() of
> > > perf_event fd.
> > >
> > > This commit refactors samples that attach the bpf program to perf_event
> > > by using libbbpf instead of ioctl. Also the bpf_load in the samples were
> > > removed and migrated to use libbbpf API.
> > >
> > > Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
> > > ---
> > > Changes in v2:
> > > - check memory allocation is successful
> > > - clean up allocated memory on error
> > >
> > > Changes in v3:
> > > - Improve pointer error check (IS_ERR())
> > > - change to calloc for easier destroy of bpf_link
> > > - remove perf_event fd list since bpf_link handles fd
> > > - use newer bpf_object__{open/load} API instead of bpf_prog_load
> > > - perf_event for _SC_NPROCESSORS_ONLN instead of _SC_NPROCESSORS_CONF
> > > - find program with name explicitly instead of bpf_program__next
> > > - unconditional bpf_link__destroy() on cleanup
> > > - return error code on int_exit
> > >
> > > samples/bpf/Makefile | 4 +-
> > > samples/bpf/sampleip_user.c | 100 ++++++++++++++++++++++-----------
> > > samples/bpf/trace_event_user.c | 89 ++++++++++++++++++++---------
> > > 3 files changed, 131 insertions(+), 62 deletions(-)
> > >
> > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> > > index ff0061467dd3..424f6fe7ce38 100644
> > > --- a/samples/bpf/Makefile
> > > +++ b/samples/bpf/Makefile
> > > @@ -88,8 +88,8 @@ xdp2-objs := xdp1_user.o
> > > xdp_router_ipv4-objs := xdp_router_ipv4_user.o
> > > test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
> > > test_current_task_under_cgroup_user.o
> > > -trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
> > > -sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
> > > +trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
> > > +sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
> > > tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
> > > lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
> > > xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
> > > diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
> > > index b0f115f938bc..05eca7b00e22 100644
> > > --- a/samples/bpf/sampleip_user.c
> > > +++ b/samples/bpf/sampleip_user.c
> > > @@ -10,21 +10,23 @@
> > > #include <errno.h>
> > > #include <signal.h>
> > > #include <string.h>
> > > -#include <assert.h>
> > > #include <linux/perf_event.h>
> > > #include <linux/ptrace.h>
> > > #include <linux/bpf.h>
> > > -#include <sys/ioctl.h>
> > > +#include <bpf/bpf.h>
> > > #include <bpf/libbpf.h>
> > > -#include "bpf_load.h"
> > > #include "perf-sys.h"
> > > #include "trace_helpers.h"
> > >
> > > +#define __must_check
> > > +#include <linux/err.h>
> > > +
> > > #define DEFAULT_FREQ 99
> > > #define DEFAULT_SECS 5
> > > #define MAX_IPS 8192
> > > #define PAGE_OFFSET 0xffff880000000000
> > >
> > > +static int map_fd;
> > > static int nr_cpus;
> > >
> > > static void usage(void)
> > > @@ -34,9 +36,10 @@ static void usage(void)
> > > printf(" duration # sampling duration (seconds), default 5\n");
> > > }
> > >
> > > -static int sampling_start(int *pmu_fd, int freq)
> > > +static int sampling_start(int freq, struct bpf_program *prog,
> > > + struct bpf_link *links[])
> > > {
> > > - int i;
> > > + int i, pmu_fd;
> > >
> > > struct perf_event_attr pe_sample_attr = {
> > > .type = PERF_TYPE_SOFTWARE,
> > > @@ -47,26 +50,29 @@ static int sampling_start(int *pmu_fd, int freq)
> > > };
> > >
> > > for (i = 0; i < nr_cpus; i++) {
> > > - pmu_fd[i] = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
> > > + pmu_fd = sys_perf_event_open(&pe_sample_attr, -1 /* pid */, i,
> > > -1 /* group_fd */, 0 /* flags */);
> > > - if (pmu_fd[i] < 0) {
> > > + if (pmu_fd < 0) {
> > > fprintf(stderr, "ERROR: Initializing perf sampling\n");
> > > return 1;
> > > }
> > > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF,
> > > - prog_fd[0]) == 0);
> > > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
> > > + links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
> > > + if (IS_ERR(links[i])) {
> >
> > links[i] = NULL;
> >
>
> Since bpf_program__attach_perf_event will return err code such
> as ERR_PTR(-EINVAL), so it is natural to reset the pointer to NULL!
> Thank you for the heads up!
>
> > > + fprintf(stderr, "ERROR: Attach perf event\n");
> > > + close(pmu_fd);
> > > + return 1;
> > > + }
> > > }
> > >
> > > return 0;
> > > }
> > >
> > > -static void sampling_end(int *pmu_fd)
> > > +static void sampling_end(struct bpf_link *links[])
> > > {
> > > int i;
> > >
> > > for (i = 0; i < nr_cpus; i++)
> > > - close(pmu_fd[i]);
> > > + bpf_link__destroy(links[i]);
> > > }
> > >
> > > struct ipcount {
> > > @@ -128,14 +134,17 @@ static void print_ip_map(int fd)
> > > static void int_exit(int sig)
> > > {
> > > printf("\n");
> > > - print_ip_map(map_fd[0]);
> > > + print_ip_map(map_fd);
> > > exit(0);
> > > }
> > >
> > > int main(int argc, char **argv)
> > > {
> > > + int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 0;
> > > + struct bpf_program *prog;
> > > + struct bpf_object *obj;
> >
> > initialize to NULL here
> >
>
> I'll apply this at next version patch.
>
> > > + struct bpf_link **links;
> > > char filename[256];
> > > - int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
> > >
> > > /* process arguments */
> > > while ((opt = getopt(argc, argv, "F:h")) != -1) {
> > > @@ -163,38 +172,61 @@ int main(int argc, char **argv)
> > > }
> > >
> > > /* create perf FDs for each CPU */
> > > - nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > > - pmu_fd = malloc(nr_cpus * sizeof(int));
> > > - if (pmu_fd == NULL) {
> > > - fprintf(stderr, "ERROR: malloc of pmu_fd\n");
> > > - return 1;
> > > + nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> > > + links = calloc(nr_cpus, sizeof(struct bpf_link *));
> > > + if (!links) {
> > > + fprintf(stderr, "ERROR: malloc of links\n");
> > > + error = 1;
> > > + goto cleanup;
> > > }
> > >
> > > - /* load BPF program */
> > > snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> > > - if (load_bpf_file(filename)) {
> > > - fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
> > > - errno);
> > > - if (strcmp(bpf_log_buf, "") == 0)
> > > - fprintf(stderr, "Try: ulimit -l unlimited\n");
> > > - else
> > > - fprintf(stderr, "%s", bpf_log_buf);
> > > - return 1;
> > > + obj = bpf_object__open_file(filename, NULL);
> > > + if (IS_ERR(obj)) {
> >
> > obj = NULL;
> >
>
> Also again, bpf_object__open_file will return err code of pointer,
> and the pointer needs to be set to NULL for bpf_object__close.
>
> > > + fprintf(stderr, "ERROR: opening BPF object file failed\n");
> > > + error = 1;
> > > + goto cleanup;
> > > + }
> > > +
> > > + prog = bpf_object__find_program_by_name(obj, "do_sample");
> > > + if (!prog) {
> > > + fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
> > > + error = 1;
> > > + goto cleanup;
> > > }
> > > +
> > > + /* load BPF program */
> > > + if (bpf_object__load(obj)) {
> > > + fprintf(stderr, "ERROR: loading BPF object file failed\n");
> > > + error = 1;
> > > + goto cleanup;
> > > + }
> > > +
> > > + map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
> > > + if (map_fd < 0) {
> > > + fprintf(stderr, "ERROR: finding a map in obj file failed\n");
> > > + error = 1;
> > > + goto cleanup;
> > > + }
> > > +
> > > signal(SIGINT, int_exit);
> > > signal(SIGTERM, int_exit);
> > >
> > > /* do sampling */
> > > printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
> > > freq, secs);
> > > - if (sampling_start(pmu_fd, freq) != 0)
> > > - return 1;
> > > + if (sampling_start(freq, prog, links) != 0) {
> > > + error = 1;
> > > + goto cleanup;
> > > + }
> > > sleep(secs);
> > > - sampling_end(pmu_fd);
> > > - free(pmu_fd);
> > >
> > > +cleanup:
> > > + sampling_end(links);
> >
> > bpf_object__destroy(obj)
> >
>
> Sorry, but I might not following you, but is there bpf_object__destroy
> exist in libbpf? I guess you're talking about bpf_object__close, right?
Yeah, I meant bpf_object__close, sorry.
>
> > > /* output sample counts */
> > > - print_ip_map(map_fd[0]);
> > > + if (!error)
> > > + print_ip_map(map_fd);
> > >
> > > - return 0;
> > > + free(links);
> > > + return error;
> > > }
> > > diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
> > > index 356171bc392b..5f64ff524cc3 100644
> > > --- a/samples/bpf/trace_event_user.c
> > > +++ b/samples/bpf/trace_event_user.c
> > > @@ -6,22 +6,24 @@
> > > #include <stdlib.h>
> > > #include <stdbool.h>
> > > #include <string.h>
> > > -#include <fcntl.h>
> > > -#include <poll.h>
> > > -#include <sys/ioctl.h>
> > > #include <linux/perf_event.h>
> > > #include <linux/bpf.h>
> > > #include <signal.h>
> > > -#include <assert.h>
> > > #include <errno.h>
> > > #include <sys/resource.h>
> > > +#include <bpf/bpf.h>
> > > #include <bpf/libbpf.h>
> > > -#include "bpf_load.h"
> > > #include "perf-sys.h"
> > > #include "trace_helpers.h"
> > >
> > > +#define __must_check
> > > +#include <linux/err.h>
> > > +
> > > #define SAMPLE_FREQ 50
> > >
> > > +/* counts, stackmap */
> > > +static int map_fd[2];
> > > +struct bpf_program *prog;
> > > static bool sys_read_seen, sys_write_seen;
> > >
> > > static void print_ksym(__u64 addr)
> > > @@ -136,23 +138,34 @@ static inline int generate_load(void)
> > >
> > > static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > > {
> > > - int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > > - int *pmu_fd = malloc(nr_cpus * sizeof(int));
> > > - int i, error = 0;
> > > + int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> > > + struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
> > > + int i, pmu_fd, error = 0;
> > > +
> > > + if (!links) {
> > > + printf("malloc of links failed\n");
> > > + error = 1;
> > > + goto err;
> > > + }
> > >
> > > /* system wide perf event, no need to inherit */
> > > attr->inherit = 0;
> > >
> > > /* open perf_event on all cpus */
> > > for (i = 0; i < nr_cpus; i++) {
> > > - pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
> > > - if (pmu_fd[i] < 0) {
> > > + pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
> > > + if (pmu_fd < 0) {
> > > printf("sys_perf_event_open failed\n");
> > > error = 1;
> > > goto all_cpu_err;
> > > }
> > > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> > > - assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
> > > + links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
> > > + if (IS_ERR(links[i])) {
> > > + printf("bpf_program__attach_perf_event failed\n");
> > > + close(pmu_fd);
> > > + error = 1;
> > > + goto all_cpu_err;
> > > + }
> > > }
> > >
> > > if (generate_load() < 0) {
> > > @@ -161,18 +174,18 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
> > > }
> > > print_stacks();
> > > all_cpu_err:
> > > - for (i--; i >= 0; i--) {
> > > - ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
> > > - close(pmu_fd[i]);
> > > - }
> > > - free(pmu_fd);
> > > + for (i--; i >= 0; i--)
> > > + bpf_link__destroy(links[i]);
> > > +err:
> > > + free(links);
> > > if (error)
> > > - int_exit(0);
> > > + int_exit(error);
> > > }
> > >
> > > static void test_perf_event_task(struct perf_event_attr *attr)
> > > {
> > > int pmu_fd, error = 0;
> > > + struct bpf_link *link;
> > >
> > > /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
> > > * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
> > > @@ -185,8 +198,12 @@ static void test_perf_event_task(struct perf_event_attr *attr)
> > > printf("sys_perf_event_open failed\n");
> > > int_exit(0);
> > > }
> > > - assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
> > > - assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
> > > + link = bpf_program__attach_perf_event(prog, pmu_fd);
> > > + if (IS_ERR(link)) {
> > > + printf("bpf_program__attach_perf_event failed\n");
> > > + close(pmu_fd);
> > > + int_exit(0);
> > > + }
> > >
> > > if (generate_load() < 0) {
> > > error = 1;
> > > @@ -194,10 +211,9 @@ static void test_perf_event_task(struct perf_event_attr *attr)
> > > }
> > > print_stacks();
> > > err:
> > > - ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
> > > - close(pmu_fd);
> > > + bpf_link__destroy(link);
> > > if (error)
> > > - int_exit(0);
> > > + int_exit(error);
> > > }
> > >
> > > static void test_bpf_perf_event(void)
> > > @@ -282,6 +298,7 @@ static void test_bpf_perf_event(void)
> > > int main(int argc, char **argv)
> > > {
> > > struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
> > > + struct bpf_object *obj;
> > > char filename[256];
> > >
> > > snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
> > > @@ -295,9 +312,29 @@ int main(int argc, char **argv)
> > > return 1;
> > > }
> > >
> > > - if (load_bpf_file(filename)) {
> > > - printf("%s", bpf_log_buf);
> > > - return 2;
> > > + obj = bpf_object__open_file(filename, NULL);
> > > + if (IS_ERR(obj)) {
> > > + printf("opening BPF object file failed\n");
> > > + return 1;
> > > + }
> > > +
> > > + prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
> > > + if (!prog) {
> > > + printf("finding a prog in obj file failed\n");
> >
> >
> > bpf_object__close(obj);
> >
>
> Also, I'll apply this at next version patch.
>
> > > + return 1;
> > > + }
> > > +
> > > + /* load BPF program */
> > > + if (bpf_object__load(obj)) {
> >
> > close bpf_object (better do goto clean approach, of course)
> >
>
> I will modify this with goto cleanup approach.
>
> > > + printf("loading BPF object file failed\n");
> > > + return 1;
> > > + }
> > > +
> > > + 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) {
> > > + printf("finding a counts/stackmap map in obj file failed\n");
> > > + return 1;
> > > }
> > >
> > > if (fork() == 0) {
> > > --
> > > 2.25.1
> > >
>
> Thank you for your time and effort for the review :)
>
> Best,
> Daniel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-03-14 1:48 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-13 11:52 [PATCH bpf-next v3 0/2] Refactor perf_event sample user program with libbpf bpf_link Daniel T. Lee
2020-03-13 11:52 ` [PATCH bpf-next v3 1/2] samples: bpf: move read_trace_pipe to trace_helpers Daniel T. Lee
2020-03-13 11:52 ` [PATCH bpf-next v3 2/2] samples: bpf: refactor perf_event user program with libbpf bpf_link Daniel T. Lee
2020-03-13 18:48 ` Andrii Nakryiko
2020-03-14 1:45 ` Daniel T. Lee
2020-03-14 1:48 ` Andrii Nakryiko
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