There're some random failure for split_huge_page_test when khugepaged collapses pages into pmd again which had split by the test.
Prevent the khugepaged's collapses for split page by setting the mapped pmd-huge-page with MADV_NOHUGEPAGE before split. Reported-by: Kevin Brodsky <[email protected]> Reviewed-by: Zi Yan <[email protected]> Signed-off-by: Yeoreum Yun <[email protected]> --- tools/testing/selftests/mm/split_huge_page_test.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 86a603692826..c718269a291f 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -180,6 +180,10 @@ static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hp if (!rss_anon_before) ksft_exit_fail_msg("No RssAnon is allocated before split\n"); + /* Prevent khugepaged from collapsing the pages. */ + if (madvise(one_page, len, MADV_NOHUGEPAGE)) + ksft_print_msg("madvise(MADV_NOHUGEPAGE) failed\n"); + /* split all THPs */ write_debugfs(PID_FMT, getpid(), (uint64_t)one_page, (uint64_t)one_page + len, 0); @@ -227,6 +231,10 @@ static void split_pmd_thp_to_order(int order) if (!check_huge_anon(one_page, 4 * pmd_pagesize, 4, pmd_pagesize)) ksft_exit_fail_msg("No THP is allocated\n"); + /* Prevent khugepaged from collapsing the pages. */ + if (madvise(one_page, len, MADV_NOHUGEPAGE)) + ksft_print_msg("madvise(MADV_NOHUGEPAGE) failed\n"); + /* split all THPs */ write_debugfs(PID_FMT, getpid(), (uint64_t)one_page, (uint64_t)one_page + len, order); @@ -313,6 +321,10 @@ static void split_pte_mapped_thp(void) goto out; } + /* Prevent khugepaged from collapsing the pages. */ + if (madvise(thp_area, thp_area_size, MADV_NOHUGEPAGE)) + ksft_print_msg("madvise(MADV_NOHUGEPAGE) failed\n"); + /* Split all THPs through the remapped pages. */ write_debugfs(PID_FMT, getpid(), (uint64_t)page_area, (uint64_t)page_area + page_area_size, 0); @@ -542,6 +554,9 @@ static int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, ksft_test_result_skip("Pagecache folio split skipped\n"); return -2; } + /* Prevent khugepaged from collapsing the pages. */ + if (madvise(*addr, fd_size, MADV_NOHUGEPAGE)) + ksft_print_msg("madvise(MADV_NOHUGEPAGE) failed\n"); return 0; err_out_close: close(*fd); -- 2.43.0
