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| author | Vincent Donnefort <vdonnefort@google.com> | 2024-06-28 13:46:11 +0300 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2024-08-26 20:42:23 +0300 |
| commit | eb2dcde9f970ed8d3669444d47c8524b4bdf7d32 (patch) | |
| tree | fce2721f068acd2461f8d315c4c2406383348a56 /tools | |
| parent | d0f2d6e9512ecf4306c4432761f04bd35cf9e3a6 (diff) | |
| download | linux-eb2dcde9f970ed8d3669444d47c8524b4bdf7d32.tar.xz | |
ring-buffer: Align meta-page to sub-buffers for improved TLB usage
Previously, the mapped ring-buffer layout caused misalignment between
the meta-page and sub-buffers when the sub-buffer size was not a
multiple of PAGE_SIZE. This prevented hardware with larger TLB entries
from utilizing them effectively.
Add a padding with the zero-page between the meta-page and sub-buffers.
Also update the ring-buffer map_test to verify that padding.
Link: https://lore.kernel.org/20240628104611.1443542-1-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/ring-buffer/map_test.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/testing/selftests/ring-buffer/map_test.c b/tools/testing/selftests/ring-buffer/map_test.c index a9006fa7097e..4bb0192e43f3 100644 --- a/tools/testing/selftests/ring-buffer/map_test.c +++ b/tools/testing/selftests/ring-buffer/map_test.c @@ -228,6 +228,20 @@ TEST_F(map, data_mmap) data = mmap(NULL, data_len, PROT_READ, MAP_SHARED, desc->cpu_fd, meta_len); ASSERT_EQ(data, MAP_FAILED); + + /* 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); + munmap(data, data_len); + } } FIXTURE(snapshot) { |