On Thu, Apr 25, 2024 at 04:06:27PM +0200, Andrea Righi wrote: > Add a testcase for the ring_buffer__consume_n() API. > > The test produces multiple samples in a ring buffer, using a > sys_getpid() fentry prog, and consumes them from user-space in batches, > rather than consuming all of them greedily, like ring_buffer__consume() > does. > > Link: https://lore.kernel.org/lkml/CAEf4BzaR4zqUpDmj44KNLdpJ=Tpa97GrvzuzVNO5nM6b7oWd1w@xxxxxxxxxxxxxx > Signed-off-by: Andrea Righi <andrea.righi@xxxxxxxxxxxxx> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx> jirka > --- > tools/testing/selftests/bpf/Makefile | 2 +- > .../selftests/bpf/prog_tests/ringbuf.c | 64 +++++++++++++++++++ > .../selftests/bpf/progs/test_ringbuf_n.c | 47 ++++++++++++++ > 3 files changed, 112 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/bpf/progs/test_ringbuf_n.c > > ChangeLog v2 -> v3: > - move skel_n inside ringbuf_n_subtest() > > ChangeLog v1 -> v2: > - replace CHECK() with ASSERT_EQ() > - fix skel -> skel_n > - drop unused "seq" field from struct sample > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile > index edc73f8f5aef..6332277edeca 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -455,7 +455,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \ > LSKELS := fentry_test.c fexit_test.c fexit_sleep.c atomics.c \ > trace_printk.c trace_vprintk.c map_ptr_kern.c \ > core_kern.c core_kern_overflow.c test_ringbuf.c \ > - test_ringbuf_map_key.c > + test_ringbuf_n.c test_ringbuf_map_key.c > > # Generate both light skeleton and libbpf skeleton for these > LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \ > diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c > index 48c5695b7abf..2f064d6952f0 100644 > --- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c > +++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c > @@ -13,6 +13,7 @@ > #include <linux/perf_event.h> > #include <linux/ring_buffer.h> > #include "test_ringbuf.lskel.h" > +#include "test_ringbuf_n.lskel.h" > #include "test_ringbuf_map_key.lskel.h" > > #define EDONE 7777 > @@ -326,6 +327,67 @@ static void ringbuf_subtest(void) > test_ringbuf_lskel__destroy(skel); > } > > +/* > + * Test ring_buffer__consume_n() by producing N_TOT_SAMPLES samples in the ring > + * buffer, via getpid(), and consuming them in chunks of N_SAMPLES. > + */ > +#define N_TOT_SAMPLES 32 > +#define N_SAMPLES 4 > + > +/* Sample value to verify the callback validity */ > +#define SAMPLE_VALUE 42L > + > +static int process_n_sample(void *ctx, void *data, size_t len) > +{ > + struct sample *s = data; > + > + ASSERT_EQ(s->value, SAMPLE_VALUE, "sample_value"); > + > + return 0; > +} > + > +static void ringbuf_n_subtest(void) > +{ > + struct test_ringbuf_n_lskel *skel_n; > + int err, i; > + > + skel_n = test_ringbuf_n_lskel__open(); > + if (!ASSERT_OK_PTR(skel_n, "test_ringbuf_n_lskel__open")) > + return; > + > + skel_n->maps.ringbuf.max_entries = getpagesize(); > + skel_n->bss->pid = getpid(); > + > + err = test_ringbuf_n_lskel__load(skel_n); > + if (!ASSERT_OK(err, "test_ringbuf_n_lskel__load")) > + goto cleanup; > + > + ringbuf = ring_buffer__new(skel_n->maps.ringbuf.map_fd, > + process_n_sample, NULL, NULL); > + if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new")) > + goto cleanup; > + > + err = test_ringbuf_n_lskel__attach(skel_n); > + if (!ASSERT_OK(err, "test_ringbuf_n_lskel__attach")) > + goto cleanup_ringbuf; > + > + /* Produce N_TOT_SAMPLES samples in the ring buffer by calling getpid() */ > + skel_n->bss->value = SAMPLE_VALUE; > + for (i = 0; i < N_TOT_SAMPLES; i++) > + syscall(__NR_getpgid); > + > + /* Consume all samples from the ring buffer in batches of N_SAMPLES */ > + for (i = 0; i < N_TOT_SAMPLES; i += err) { > + err = ring_buffer__consume_n(ringbuf, N_SAMPLES); > + ASSERT_EQ(err, N_SAMPLES, "rb_consume"); > + } > + > +cleanup_ringbuf: > + ring_buffer__free(ringbuf); > +cleanup: > + test_ringbuf_n_lskel__destroy(skel_n); > +} > + > static int process_map_key_sample(void *ctx, void *data, size_t len) > { > struct sample *s; > @@ -384,6 +446,8 @@ void test_ringbuf(void) > { > if (test__start_subtest("ringbuf")) > ringbuf_subtest(); > + if (test__start_subtest("ringbuf_n")) > + ringbuf_n_subtest(); > if (test__start_subtest("ringbuf_map_key")) > ringbuf_map_key_subtest(); > } > diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_n.c b/tools/testing/selftests/bpf/progs/test_ringbuf_n.c > new file mode 100644 > index 000000000000..8669eb42dbe0 > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/test_ringbuf_n.c > @@ -0,0 +1,47 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (c) 2024 Andrea Righi <andrea.righi@xxxxxxxxxxxxx> > + > +#include <linux/bpf.h> > +#include <sched.h> > +#include <unistd.h> > +#include <bpf/bpf_helpers.h> > +#include "bpf_misc.h" > + > +char _license[] SEC("license") = "GPL"; > + > +#define TASK_COMM_LEN 16 > + > +struct sample { > + int pid; > + long value; > + char comm[16]; > +}; > + > +struct { > + __uint(type, BPF_MAP_TYPE_RINGBUF); > +} ringbuf SEC(".maps"); > + > +int pid = 0; > +long value = 0; > + > +SEC("fentry/" SYS_PREFIX "sys_getpgid") > +int test_ringbuf_n(void *ctx) > +{ > + int cur_pid = bpf_get_current_pid_tgid() >> 32; > + struct sample *sample; > + > + if (cur_pid != pid) > + return 0; > + > + sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0); > + if (!sample) > + return 0; > + > + sample->pid = pid; > + sample->value = value; > + bpf_get_current_comm(sample->comm, sizeof(sample->comm)); > + > + bpf_ringbuf_submit(sample, 0); > + > + return 0; > +} > -- > 2.43.0 >
