From 8c583e538aa681ecb293d5606054de70f44b5558 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Mon, 7 Apr 2025 19:31:35 +0800 Subject: [PATCH] selftests: mincore: fix tmpfs mincore test failure When running mincore test cases, I encountered the following failures: " mincore_selftest.c:359:check_tmpfs_mmap:Expected ra_pages (511) == 0 (0) mincore_selftest.c:360:check_tmpfs_mmap:Read-ahead pages found in memory check_tmpfs_mmap: Test terminated by assertion FAIL global.check_tmpfs_mmap not ok 5 global.check_tmpfs_mmap FAILED: 4 / 5 tests passed " The reason for the test case failure is that my system automatically enabled tmpfs large folio allocation by adding the 'transparent_hugepage_tmpfs=always' cmdline. However, the test case still expects the tmpfs mounted on /dev/shm to allocate small folios, which leads to assertion failures when verifying readahead pages. As discussed with David, there's no reason to continue checking the readahead logic for tmpfs. Drop it to fix this issue. Link: https://lkml.kernel.org/r/9a00856cc6a8b4e46f4ab8b1af11ce5fc1a31851.1744025467.git.baolin.wang@linux.alibaba.com Fixes: d635ccdb435c ("mm: shmem: add a kernel command line to change the default huge policy for tmpfs") Signed-off-by: Baolin Wang Acked-by: Zi Yan Acked-by: David Hildenbrand Cc: Barry Song <21cnbao@gmail.com> Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Ryan Roberts Signed-off-by: Andrew Morton --- .../testing/selftests/mincore/mincore_selftest.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/mincore/mincore_selftest.c b/tools/testing/selftests/mincore/mincore_selftest.c index e949a43a61450..0fd4b00bd345b 100644 --- a/tools/testing/selftests/mincore/mincore_selftest.c +++ b/tools/testing/selftests/mincore/mincore_selftest.c @@ -286,8 +286,7 @@ out_free: /* * Test mincore() behavior on a page backed by a tmpfs file. This test - * performs the same steps as the previous one. However, we don't expect - * any readahead in this case. + * performs the same steps as the previous one. */ TEST(check_tmpfs_mmap) { @@ -298,7 +297,6 @@ TEST(check_tmpfs_mmap) int page_size; int fd; int i; - int ra_pages = 0; page_size = sysconf(_SC_PAGESIZE); vec_size = FILE_SIZE / page_size; @@ -341,8 +339,7 @@ TEST(check_tmpfs_mmap) } /* - * Touch a page in the middle of the mapping. We expect only - * that page to be fetched into memory. + * Touch a page in the middle of the mapping. */ addr[FILE_SIZE / 2] = 1; retval = mincore(addr, FILE_SIZE, vec); @@ -351,15 +348,6 @@ TEST(check_tmpfs_mmap) TH_LOG("Page not found in memory after use"); } - i = FILE_SIZE / 2 / page_size + 1; - while (i < vec_size && vec[i]) { - ra_pages++; - i++; - } - ASSERT_EQ(ra_pages, 0) { - TH_LOG("Read-ahead pages found in memory"); - } - munmap(addr, FILE_SIZE); close(fd); free(vec); -- 2.39.5