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From:   "Joel Fernandes (Google)" <joel@joelfernandes.org>
To:     linux-kernel@vger.kernel.org
Cc:     "Joel Fernandes (Google)" <joel@joelfernandes.org>,
        linux-kselftest@vger.kernel.org, linux-mm@kvack.org,
        Shuah Khan <shuah@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Hocko <mhocko@suse.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Lorenzo Stoakes <lstoakes@gmail.com>,
        Kirill A Shutemov <kirill@shutemov.name>,
        "Liam R. Howlett" <liam.howlett@oracle.com>,
        "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH RFC 3/4] selftests: mm: Add a test for mutually aligned moves > PMD size
Date:   Thu, 18 May 2023 02:18:24 +0000
Message-ID: <20230518021825.712742-4-joel@joelfernandes.org>
In-Reply-To: <20230518021825.712742-1-joel@joelfernandes.org>
References: <20230518021825.712742-1-joel@joelfernandes.org>
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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@joelfernandes.org>
---
 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");
 	/*
-- 
2.40.1.606.ga4b1b128d6-goog