From: Sayali Patil Date: Thu, 21 May 2026 06:47:46 +0000 (+0530) Subject: selftests/mm: size tmpfs according to PMD page size in split_huge_page_test X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a2dde8a065d5c8d63b53b1c8f035017e4aeac0c2;p=thirdparty%2Flinux.git selftests/mm: size tmpfs according to PMD page size in split_huge_page_test The split_file_backed_thp() test mounts a tmpfs with a fixed size of "4m". This works on systems with smaller PMD page sizes, but fails on configurations where the PMD huge page size is larger (e.g. 16MB). On such systems, the fixed 4MB tmpfs is insufficient to allocate even a single PMD-sized THP, causing the test to fail. Fix this by sizing the tmpfs dynamically based on the runtime pmd_pagesize, allocating space for two PMD-sized pages. Before patch: running ./split_huge_page_test /tmp/xfs_dir_YTrI5E -------------------------------------------------- TAP version 13 1..55 ok 1 Split zero filled huge pages successful ok 2 Split huge pages to order 0 successful ok 3 Split huge pages to order 2 successful ok 4 Split huge pages to order 3 successful ok 5 Split huge pages to order 4 successful ok 6 Split huge pages to order 5 successful ok 7 Split huge pages to order 6 successful ok 8 Split huge pages to order 7 successful ok 9 Split PTE-mapped huge pages successful Please enable pr_debug in split_huge_pages_in_file() for more info. Failed to write data to testing file: Success (0) Bail out! Error occurred Planned tests != run tests (55 != 9) Totals: pass:9 fail:0 xfail:0 xpass:0 skip:0 error:0 [FAIL] After patch: running ./split_huge_page_test /tmp/xfs_dir_bMvj6o -------------------------------------------------- TAP version 13 1..55 ok 1 Split zero filled huge pages successful ok 2 Split huge pages to order 0 successful ok 3 Split huge pages to order 2 successful ok 4 Split huge pages to order 3 successful ok 5 Split huge pages to order 4 successful ok 6 Split huge pages to order 5 successful ok 7 Split huge pages to order 6 successful ok 8 Split huge pages to order 7 successful ok 9 Split PTE-mapped huge pages successful Please enable pr_debug in split_huge_pages_in_file() for more info. Please check dmesg for more information ok 10 File-backed THP split to order 0 test done Please enable pr_debug in split_huge_pages_in_file() for more info. Please check dmesg for more information ok 11 File-backed THP split to order 1 test done Please enable pr_debug in split_huge_pages_in_file() for more info. Please check dmesg for more information ok 12 File-backed THP split to order 2 test done ... ok 55 Split PMD-mapped pagecache folio to order 7 at in-folio offset 128 passed Totals: pass:55 fail:0 xfail:0 xpass:0 skip:0 error:0 [PASS] ok 1 split_huge_page_test /tmp/xfs_dir_bMvj6o Link: https://lore.kernel.org/33e1bc10753fe82d1217613d8cd496020778cf2b.1779296493.git.sayalip@linux.ibm.com Fixes: fbe37501b252 ("mm: huge_memory: debugfs for file-backed THP split") Signed-off-by: Sayali Patil Reviewed-by: Zi Yan Reviewed-by: David Hildenbrand (Arm) Tested-by: Venkat Rao Bagalkote Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Signed-off-by: Andrew Morton --- diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index a1ccfabc53675..9a50557069ad2 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -470,6 +470,8 @@ static void split_file_backed_thp(int order) char tmpfs_template[] = "/tmp/thp_split_XXXXXX"; const char *tmpfs_loc = mkdtemp(tmpfs_template); char testfile[INPUT_MAX]; + unsigned long size = 2 * pmd_pagesize; + char opts[64]; ssize_t num_written, num_read; char *file_buf1, *file_buf2; uint64_t pgoff_start = 0, pgoff_end = 1024; @@ -489,7 +491,8 @@ static void split_file_backed_thp(int order) file_buf1[i] = (char)i; memset(file_buf2, 0, pmd_pagesize); - status = mount("tmpfs", tmpfs_loc, "tmpfs", 0, "huge=always,size=4m"); + snprintf(opts, sizeof(opts), "huge=always,size=%lu", size); + status = mount("tmpfs", tmpfs_loc, "tmpfs", 0, opts); if (status) ksft_exit_fail_msg("Unable to create a tmpfs for testing\n");