[PATCH v5 4/7] selftests: mm: Add a test for mutually aligned moves > PMD size

From: Joel Fernandes (Google)
Date: Mon Aug 21 2023 - 21:55:52 EST


This patch adds a test case to check if a PMD-alignment optimization
successfully happens.

I add support to make sure there is some room before the source mapping,
otherwise the optimization to trigger PMD-aligned move will be disabled
as the kernel will detect that a mapping before the source exists and
such optimization becomes impossible.

Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/mm/mremap_test.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c
index 6822d657f589..6304eb0947a3 100644
--- a/tools/testing/selftests/mm/mremap_test.c
+++ b/tools/testing/selftests/mm/mremap_test.c
@@ -44,6 +44,7 @@ enum {
_1MB = 1ULL << 20,
_2MB = 2ULL << 20,
_4MB = 4ULL << 20,
+ _5MB = 5ULL << 20,
_1GB = 1ULL << 30,
_2GB = 2ULL << 30,
PMD = _2MB,
@@ -235,6 +236,11 @@ static void *get_source_mapping(struct config c)
unsigned long long mmap_min_addr;

mmap_min_addr = get_mmap_min_addr();
+ /*
+ * For some tests, we need to not have any mappings below the
+ * source mapping. Add some headroom to mmap_min_addr for this.
+ */
+ mmap_min_addr += 10 * _4MB;

retry:
addr += c.src_alignment;
@@ -434,7 +440,7 @@ static int parse_args(int argc, char **argv, unsigned int *threshold_mb,
return 0;
}

-#define MAX_TEST 13
+#define MAX_TEST 14
#define MAX_PERF_TEST 3
int main(int argc, char **argv)
{
@@ -500,6 +506,10 @@ int main(int argc, char **argv)
test_cases[12] = MAKE_TEST(PUD, PUD, _2GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"2GB mremap - Source PUD-aligned, Destination PUD-aligned");

+ /* Src and Dest addr 1MB aligned. 5MB mremap. */
+ test_cases[13] = MAKE_TEST(_1MB, _1MB, _5MB, NON_OVERLAPPING, EXPECT_SUCCESS,
+ "5MB mremap - Source 1MB-aligned, Destination 1MB-aligned");
+
perf_test_cases[0] = MAKE_TEST(page_size, page_size, _1GB, NON_OVERLAPPING, EXPECT_SUCCESS,
"1GB mremap - Source PTE-aligned, Destination PTE-aligned");
/*
--
2.42.0.rc1.204.g551eb34607-goog