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// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <linux/compiler.h>
#include <asm/barrier.h>
#include <test_progs.h>
#include <sys/mman.h>
#include <sys/epoll.h>
#include <time.h>
#include <sched.h>
#include <signal.h>
#include <pthread.h>
#include <sys/sysinfo.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include "test_ringbuf.skel.h"
#define EDONE 7777
static int duration = 0;
struct sample {
int pid;
int seq;
long value;
char comm[16];
};
static int sample_cnt;
static void atomic_inc(int *cnt)
{
__atomic_add_fetch(cnt, 1, __ATOMIC_SEQ_CST);
}
static int atomic_xchg(int *cnt, int val)
{
return __atomic_exchange_n(cnt, val, __ATOMIC_SEQ_CST);
}
static int process_sample(void *ctx, void *data, size_t len)
{
struct sample *s = data;
atomic_inc(&sample_cnt);
switch (s->seq) {
case 0:
CHECK(s->value != 333, "sample1_value", "exp %ld, got %ld\n",
333L, s->value);
return 0;
case 1:
CHECK(s->value != 777, "sample2_value", "exp %ld, got %ld\n",
777L, s->value);
return -EDONE;
default:
/* we don't care about the rest */
return 0;
}
}
static struct test_ringbuf *skel;
static struct ring_buffer *ringbuf;
static void trigger_samples()
{
skel->bss->dropped = 0;
skel->bss->total = 0;
skel->bss->discarded = 0;
/* trigger exactly two samples */
skel->bss->value = 333;
syscall(__NR_getpgid);
skel->bss->value = 777;
syscall(__NR_getpgid);
}
static void *poll_thread(void *input)
{
long timeout = (long)input;
return (void *)(long)ring_buffer__poll(ringbuf, timeout);
}
void test_ringbuf(void)
{
const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample);
pthread_t thread;
long bg_ret = -1;
int err, cnt;
skel = test_ringbuf__open_and_load();
if (CHECK(!skel, "skel_open_load", "skeleton open&load failed\n"))
return;
/* only trigger BPF program for current process */
skel->bss->pid = getpid();
ringbuf = ring_buffer__new(bpf_map__fd(skel->maps.ringbuf),
process_sample, NULL, NULL);
if (CHECK(!ringbuf, "ringbuf_create", "failed to create ringbuf\n"))
goto cleanup;
err = test_ringbuf__attach(skel);
if (CHECK(err, "skel_attach", "skeleton attachment failed: %d\n", err))
goto cleanup;
trigger_samples();
/* 2 submitted + 1 discarded records */
CHECK(skel->bss->avail_data != 3 * rec_sz,
"err_avail_size", "exp %ld, got %ld\n",
3L * rec_sz, skel->bss->avail_data);
CHECK(skel->bss->ring_size != 4096,
"err_ring_size", "exp %ld, got %ld\n",
4096L, skel->bss->ring_size);
CHECK(skel->bss->cons_pos != 0,
"err_cons_pos", "exp %ld, got %ld\n",
0L, skel->bss->cons_pos);
CHECK(skel->bss->prod_pos != 3 * rec_sz,
"err_prod_pos", "exp %ld, got %ld\n",
3L * rec_sz, skel->bss->prod_pos);
/* poll for samples */
err = ring_buffer__poll(ringbuf, -1);
/* -EDONE is used as an indicator that we are done */
if (CHECK(err != -EDONE, "err_done", "done err: %d\n", err))
goto cleanup;
cnt = atomic_xchg(&sample_cnt, 0);
CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt);
/* we expect extra polling to return nothing */
err = ring_buffer__poll(ringbuf, 0);
if (CHECK(err != 0, "extra_samples", "poll result: %d\n", err))
goto cleanup;
cnt = atomic_xchg(&sample_cnt, 0);
CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
0L, skel->bss->dropped);
CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
2L, skel->bss->total);
CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
1L, skel->bss->discarded);
/* now validate consumer position is updated and returned */
trigger_samples();
CHECK(skel->bss->cons_pos != 3 * rec_sz,
"err_cons_pos", "exp %ld, got %ld\n",
3L * rec_sz, skel->bss->cons_pos);
err = ring_buffer__poll(ringbuf, -1);
CHECK(err <= 0, "poll_err", "err %d\n", err);
cnt = atomic_xchg(&sample_cnt, 0);
CHECK(cnt != 2, "cnt", "exp %d samples, got %d\n", 2, cnt);
/* start poll in background w/ long timeout */
err = pthread_create(&thread, NULL, poll_thread, (void *)(long)10000);
if (CHECK(err, "bg_poll", "pthread_create failed: %d\n", err))
goto cleanup;
/* turn off notifications now */
skel->bss->flags = BPF_RB_NO_WAKEUP;
/* give background thread a bit of a time */
usleep(50000);
trigger_samples();
/* sleeping arbitrarily is bad, but no better way to know that
* epoll_wait() **DID NOT** unblock in background thread
*/
usleep(50000);
/* background poll should still be blocked */
err = pthread_tryjoin_np(thread, (void **)&bg_ret);
if (CHECK(err != EBUSY, "try_join", "err %d\n", err))
goto cleanup;
/* BPF side did everything right */
CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
0L, skel->bss->dropped);
CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
2L, skel->bss->total);
CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
1L, skel->bss->discarded);
cnt = atomic_xchg(&sample_cnt, 0);
CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
/* clear flags to return to "adaptive" notification mode */
skel->bss->flags = 0;
/* produce new samples, no notification should be triggered, because
* consumer is now behind
*/
trigger_samples();
/* background poll should still be blocked */
err = pthread_tryjoin_np(thread, (void **)&bg_ret);
if (CHECK(err != EBUSY, "try_join", "err %d\n", err))
goto cleanup;
/* still no samples, because consumer is behind */
cnt = atomic_xchg(&sample_cnt, 0);
CHECK(cnt != 0, "cnt", "exp %d samples, got %d\n", 0, cnt);
skel->bss->dropped = 0;
skel->bss->total = 0;
skel->bss->discarded = 0;
skel->bss->value = 333;
syscall(__NR_getpgid);
/* now force notifications */
skel->bss->flags = BPF_RB_FORCE_WAKEUP;
skel->bss->value = 777;
syscall(__NR_getpgid);
/* now we should get a pending notification */
usleep(50000);
err = pthread_tryjoin_np(thread, (void **)&bg_ret);
if (CHECK(err, "join_bg", "err %d\n", err))
goto cleanup;
if (CHECK(bg_ret <= 0, "bg_ret", "epoll_wait result: %ld", bg_ret))
goto cleanup;
/* due to timing variations, there could still be non-notified
* samples, so consume them here to collect all the samples
*/
err = ring_buffer__consume(ringbuf);
CHECK(err < 0, "rb_consume", "failed: %d\b", err);
/* 3 rounds, 2 samples each */
cnt = atomic_xchg(&sample_cnt, 0);
CHECK(cnt != 6, "cnt", "exp %d samples, got %d\n", 6, cnt);
/* BPF side did everything right */
CHECK(skel->bss->dropped != 0, "err_dropped", "exp %ld, got %ld\n",
0L, skel->bss->dropped);
CHECK(skel->bss->total != 2, "err_total", "exp %ld, got %ld\n",
2L, skel->bss->total);
CHECK(skel->bss->discarded != 1, "err_discarded", "exp %ld, got %ld\n",
1L, skel->bss->discarded);
test_ringbuf__detach(skel);
cleanup:
ring_buffer__free(ringbuf);
test_ringbuf__destroy(skel);
}
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