[PATCH 0/2] ring-buffer/selftest: Meta-page testing improvements

[PATCH 0/2] ring-buffer/selftest: Meta-page testing improvements

[Vincent Donnefort]

Following the comments on the original patch [1] here's a set of 2 patches to
improve the selftest.

[1] https://lore.kernel.org/all/20240628104611.1443542-1-vdonnefort@google.com/

Vincent Donnefort (2):
  ring-buffer/selftest: Verify the entire meta-page padding
  ring-buffer/selftest: Handle meta-page bigger than the system

 tools/testing/selftests/ring-buffer/map_test.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)


base-commit: 2fcd5aff92aab479a9a89cfce2dbc9c6a9455b4f
-- 
2.46.0.598.g6f2099f65c-goog

[PATCH 1/2] ring-buffer/selftest: Verify the entire meta-page padding

[Vincent Donnefort]

Improve the ring-buffer meta-page test coverage by checking for the
entire padding region to be 0 instead of just looking at the first 4
bytes.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

diff --git a/tools/testing/selftests/ring-buffer/map_test.c b/tools/testing/selftests/ring-buffer/map_test.c
index 4bb0192e43f3..ba12fd31de87 100644
--- a/tools/testing/selftests/ring-buffer/map_test.c
+++ b/tools/testing/selftests/ring-buffer/map_test.c
@@ -231,15 +231,15 @@ TEST_F(map, data_mmap)
 
 	/* Verify meta-page padding */
 	if (desc->meta->meta_page_size > getpagesize()) {
-		void *addr;
-
 		data_len = desc->meta->meta_page_size;
 		data = mmap(NULL, data_len,
 			    PROT_READ, MAP_SHARED, desc->cpu_fd, 0);
 		ASSERT_NE(data, MAP_FAILED);
 
-		addr = (void *)((unsigned long)data + getpagesize());
-		ASSERT_EQ(*((int *)addr), 0);
+		for (int i = desc->meta->meta_struct_len;
+		     i < desc->meta->meta_page_size; i += sizeof(int))
+			ASSERT_EQ(*(int *)(data + i), 0);
+
 		munmap(data, data_len);
 	}
 }
-- 
2.46.0.598.g6f2099f65c-goog

[PATCH 2/2] ring-buffer/selftest: Handle meta-page bigger than the system

[Vincent Donnefort]

Handle the case where the meta-page content is bigger than the system
page-size. This prepares the ground for extending features covered by
the meta-page.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

diff --git a/tools/testing/selftests/ring-buffer/map_test.c b/tools/testing/selftests/ring-buffer/map_test.c
index ba12fd31de87..d10a847130fb 100644
--- a/tools/testing/selftests/ring-buffer/map_test.c
+++ b/tools/testing/selftests/ring-buffer/map_test.c
@@ -92,12 +92,22 @@ int tracefs_cpu_map(struct tracefs_cpu_map_desc *desc, int cpu)
 	if (desc->cpu_fd < 0)
 		return -ENODEV;
 
+again:
 	map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, desc->cpu_fd, 0);
 	if (map == MAP_FAILED)
 		return -errno;
 
 	desc->meta = (struct trace_buffer_meta *)map;
 
+	/* the meta-page is bigger than the original mapping */
+	if (page_size < desc->meta->meta_struct_len) {
+		int meta_page_size = desc->meta->meta_page_size;
+
+		munmap(desc->meta, page_size);
+		page_size = meta_page_size;
+		goto again;
+	}
+
 	return 0;
 }
 
-- 
2.46.0.598.g6f2099f65c-goog

Re: [PATCH 0/2] ring-buffer/selftest: Meta-page testing improvements

[Steven Rostedt]

On Tue, 10 Sep 2024 15:43:21 +0100
Vincent Donnefort <vdonnefort@google.com> wrote:

> Following the comments on the original patch [1] here's a set of 2 patches to
> improve the selftest.
> 
> [1] https://lore.kernel.org/all/20240628104611.1443542-1-vdonnefort@google.com/

This looks good, but can you resend this and Cc:

  Shuah Khan <skhan@linuxfoundation.org>
  linux-kselftest@vger.kernel.org

Thanks,

-- Steve

> 
> Vincent Donnefort (2):
>   ring-buffer/selftest: Verify the entire meta-page padding
>   ring-buffer/selftest: Handle meta-page bigger than the system
> 
>  tools/testing/selftests/ring-buffer/map_test.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> 
> base-commit: 2fcd5aff92aab479a9a89cfce2dbc9c6a9455b4f