Re: [PATCH v11 5/5] ring-buffer/selftest: Add ring-buffer mapping test

On Thu, 11 Jan 2024 16:17:12 +0000 Vincent Donnefort vdonnefort@google.com wrote:

This test maps a ring-buffer and validate the meta-page after reset and after emitting few events.

Cc: Shuah Khan shuah@kernel.org Cc: Shuah Khan skhan@linuxfoundation.org Cc: linux-kselftest@vger.kernel.org Signed-off-by: Vincent Donnefort vdonnefort@google.com

Looks good to me and tested.

Reviewed-by: Masami Hiramatsu (Google) mhiramat@kernel.org Tested-by: Masami Hiramatsu (Google) mhiramat@kernel.org

Thank you,

diff --git a/tools/testing/selftests/ring-buffer/Makefile b/tools/testing/selftests/ring-buffer/Makefile new file mode 100644 index 000000000000..627c5fa6d1ab --- /dev/null +++ b/tools/testing/selftests/ring-buffer/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +CFLAGS += -Wl,-no-as-needed -Wall +CFLAGS += $(KHDR_INCLUDES) +CFLAGS += -D_GNU_SOURCE

+TEST_GEN_PROGS = map_test

+include ../lib.mk diff --git a/tools/testing/selftests/ring-buffer/config b/tools/testing/selftests/ring-buffer/config new file mode 100644 index 000000000000..ef8214661612 --- /dev/null +++ b/tools/testing/selftests/ring-buffer/config @@ -0,0 +1 @@ +CONFIG_FTRACE=y diff --git a/tools/testing/selftests/ring-buffer/map_test.c b/tools/testing/selftests/ring-buffer/map_test.c new file mode 100644 index 000000000000..49107e8da5e9 --- /dev/null +++ b/tools/testing/selftests/ring-buffer/map_test.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Ring-buffer memory mapping tests
• • Copyright (c) 2024 Vincent Donnefort vdonnefort@google.com
• */

+#include <fcntl.h> +#include <sched.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h>

+#include <linux/trace_mmap.h>

+#include <sys/mman.h> +#include <sys/ioctl.h>

+#include "../user_events/user_events_selftests.h" /* share tracefs setup */ +#include "../kselftest_harness.h"

+#define TRACEFS_ROOT "/sys/kernel/tracing"

+static int __tracefs_write(const char *path, const char *value) +{

• FILE *file;
• file = fopen(path, "w");
• if (!file)

• return -1;
  

• fputs(value, file);
• fclose(file);
• return 0;

+}

+static int __tracefs_write_int(const char *path, int value) +{

• char *str;
• int ret;
• if (asprintf(&str, "%d", value) < 0)

• return -1;
  

• ret = __tracefs_write(path, str);
• free(str);
• return ret;

+}

+#define tracefs_write_int(path, value) \

• ASSERT_EQ(__tracefs_write_int((path), (value)), 0)

+static int tracefs_reset(void) +{

• if (__tracefs_write_int(TRACEFS_ROOT"/tracing_on", 0))

• return -1;
  

• if (__tracefs_write_int(TRACEFS_ROOT"/trace", 0))

• return -1;
  

• if (__tracefs_write(TRACEFS_ROOT"/set_event", ""))

• return -1;
  

• return 0;

+}

+FIXTURE(map) {

• struct trace_buffer_meta *meta;
• void *data;
• int cpu_fd;
• bool umount;

+};

+FIXTURE_VARIANT(map) {

• int subbuf_size;

+};

+FIXTURE_VARIANT_ADD(map, subbuf_size_4k) {

• .subbuf_size = 4,

+};

+FIXTURE_VARIANT_ADD(map, subbuf_size_8k) {

• .subbuf_size = 8,

+};

+FIXTURE_SETUP(map) +{

• int cpu = sched_getcpu(), page_size = getpagesize();
• unsigned long meta_len, data_len;
• char *cpu_path, *message;
• bool fail, umount;
• cpu_set_t cpu_mask;
• void *map;
• if (!tracefs_enabled(&message, &fail, &umount)) {

• if (fail) {
  

• 	TH_LOG("Tracefs setup failed: %s", message);
  

• 	ASSERT_FALSE(fail);
  

• }
  

• SKIP(return, "Skipping: %s", message);
  

• }
• self->umount = umount;
• ASSERT_GE(cpu, 0);
• ASSERT_EQ(tracefs_reset(), 0);
• tracefs_write_int(TRACEFS_ROOT"/buffer_subbuf_size_kb", variant->subbuf_size);
• ASSERT_GE(asprintf(&cpu_path,

• 	   TRACEFS_ROOT"/per_cpu/cpu%d/trace_pipe_raw",
  

• 	   cpu), 0);
  

• self->cpu_fd = open(cpu_path, O_RDONLY | O_NONBLOCK);
• ASSERT_GE(self->cpu_fd, 0);
• free(cpu_path);
• map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, self->cpu_fd, 0);
• ASSERT_NE(map, MAP_FAILED);
• self->meta = (struct trace_buffer_meta *)map;
• meta_len = self->meta->meta_page_size;
• data_len = self->meta->subbuf_size * self->meta->nr_subbufs;
• map = mmap(NULL, data_len, PROT_READ, MAP_SHARED, self->cpu_fd, meta_len);
• ASSERT_NE(map, MAP_FAILED);
• self->data = map;
• /*

• * Ensure generated events will be found on this very same ring-buffer.
  

• */
  

• CPU_ZERO(&cpu_mask);
• CPU_SET(cpu, &cpu_mask);
• ASSERT_EQ(sched_setaffinity(0, sizeof(cpu_mask), &cpu_mask), 0);

+}

+FIXTURE_TEARDOWN(map) +{

• tracefs_reset();
• if (self->umount)

• tracefs_unmount();
  

• munmap(self->data, self->meta->subbuf_size * self->meta->nr_subbufs);
• munmap(self->meta, self->meta->meta_page_size);
• close(self->cpu_fd);

+}

+TEST_F(map, meta_page_check) +{

• int cnt = 0;
• ASSERT_EQ(self->meta->entries, 0);
• ASSERT_EQ(self->meta->overrun, 0);
• ASSERT_EQ(self->meta->read, 0);
• ASSERT_EQ(self->meta->subbufs_touched, 0);
• ASSERT_EQ(self->meta->subbufs_lost, 0);
• ASSERT_EQ(self->meta->subbufs_read, 0);
• ASSERT_EQ(self->meta->reader.id, 0);
• ASSERT_EQ(self->meta->reader.read, 0);
• ASSERT_EQ(ioctl(self->cpu_fd, TRACE_MMAP_IOCTL_GET_READER), 0);
• ASSERT_EQ(self->meta->reader.id, 0);
• tracefs_write_int(TRACEFS_ROOT"/tracing_on", 1);
• for (int i = 0; i < 16; i++)

• tracefs_write_int(TRACEFS_ROOT"/trace_marker", i);
  

+again:

• ASSERT_EQ(ioctl(self->cpu_fd, TRACE_MMAP_IOCTL_GET_READER), 0);
• ASSERT_EQ(self->meta->entries, 16);
• ASSERT_EQ(self->meta->overrun, 0);
• ASSERT_EQ(self->meta->read, 16);
• /* subbufs_touched doesn't take into account the commit page */
• ASSERT_EQ(self->meta->subbufs_touched, 0);
• ASSERT_EQ(self->meta->subbufs_lost, 0);
• ASSERT_EQ(self->meta->subbufs_read, 1);
• ASSERT_EQ(self->meta->reader.id, 1);
• if (!(cnt++))

• goto again;
  

+}

+TEST_HARNESS_MAIN

2.43.0.275.g3460e3d667-goog