Instead of just checking the existence of PMD folios before and after folio split tests, use check_folio_orders() to check after-split folio orders.
The split ranges in split_thp_in_pagecache_to_order_at() are changed to [addr, addr + pagesize) for every pmd_pagesize. It prevents folios within the range being split multiple times due to debugfs split function always perform splits with a pagesize step for a given range.
The following tests are not changed: 1. split_pte_mapped_thp: the test already uses kpageflags to check; 2. split_file_backed_thp: no vaddr available.
Signed-off-by: Zi Yan ziy@nvidia.com --- .../selftests/mm/split_huge_page_test.c | 91 ++++++++++++++----- 1 file changed, 66 insertions(+), 25 deletions(-)
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index d2467072e752..7d898c380236 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -26,6 +26,7 @@ uint64_t pagesize; unsigned int pageshift; uint64_t pmd_pagesize; unsigned int pmd_order; +int *expected_orders;
#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" #define SMAP_PATH "/proc/self/smaps" @@ -37,6 +38,11 @@ unsigned int pmd_order;
#define GET_ORDER(nr_pages) (31 - __builtin_clz(nr_pages))
+const char *pagemap_proc = "/proc/self/pagemap"; +const char *kpageflags_proc = "/proc/kpageflags"; +int pagemap_fd; +int kpageflags_fd; + static int is_backed_by_folio(char *vaddr, int order, int pagemap_fd, int kpageflags_fd) { @@ -135,7 +141,8 @@ static int get_page_flags(char *vaddr, int pagemap_fd, int kpageflags_fd, * be recorded. Non-present vaddr is skipped. * * NOTE: the function is used to check folio orders after a split is performed, - * so it assumes [vaddr_start, len) fully maps to folios within that range. + * so it assumes [vaddr_start, len) fully maps to after-split folios within that + * range. * * Return: 0 - no error, -1 - unhandled cases */ @@ -369,6 +376,13 @@ static void split_pmd_thp_to_order(int order) if (one_page[i] != (char)i) ksft_exit_fail_msg("%ld byte corrupted\n", i);
+ memset(expected_orders, 0, sizeof(int) * (pmd_order + 1)); + expected_orders[order] = 4 << (pmd_order - order); + + if (check_after_split_folio_orders(one_page, len, pagemap_fd, + kpageflags_fd, expected_orders, + (pmd_order + 1))) + ksft_exit_fail_msg("Unexpected THP split\n");
if (!check_huge_anon(one_page, 0, pmd_pagesize)) ksft_exit_fail_msg("Still AnonHugePages not split\n"); @@ -383,22 +397,6 @@ static void split_pte_mapped_thp(void) size_t len = 4 * pmd_pagesize; uint64_t thp_size; size_t i; - const char *pagemap_template = "/proc/%d/pagemap"; - const char *kpageflags_proc = "/proc/kpageflags"; - char pagemap_proc[255]; - int pagemap_fd; - int kpageflags_fd; - - if (snprintf(pagemap_proc, 255, pagemap_template, getpid()) < 0) - ksft_exit_fail_msg("get pagemap proc error: %s\n", strerror(errno)); - - pagemap_fd = open(pagemap_proc, O_RDONLY); - if (pagemap_fd == -1) - ksft_exit_fail_msg("read pagemap: %s\n", strerror(errno)); - - kpageflags_fd = open(kpageflags_proc, O_RDONLY); - if (kpageflags_fd == -1) - ksft_exit_fail_msg("read kpageflags: %s\n", strerror(errno));
one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); @@ -456,8 +454,6 @@ static void split_pte_mapped_thp(void)
ksft_test_result_pass("Split PTE-mapped huge pages successful\n"); munmap(one_page, len); - close(pagemap_fd); - close(kpageflags_fd); }
static void split_file_backed_thp(int order) @@ -660,6 +656,7 @@ static void split_thp_in_pagecache_to_order_at(size_t fd_size, const char *fs_loc, int order, int offset) { int fd; + char *split_addr; char *addr; size_t i; char testfile[INPUT_MAX]; @@ -673,14 +670,33 @@ static void split_thp_in_pagecache_to_order_at(size_t fd_size, err = create_pagecache_thp_and_fd(testfile, fd_size, &fd, &addr); if (err) return; + err = 0;
- if (offset == -1) - write_debugfs(PID_FMT, getpid(), (uint64_t)addr, - (uint64_t)addr + fd_size, order); - else - write_debugfs(PID_FMT_OFFSET, getpid(), (uint64_t)addr, - (uint64_t)addr + fd_size, order, offset); + memset(expected_orders, 0, sizeof(int) * (pmd_order + 1)); + /* + * use [split_addr, split_addr + pagesize) range to split THPs, since + * the debugfs function always split a range with pagesize step and + * providing a full [addr, addr + fd_size) range can trigger multiple + * splits, complicating after-split result checking. + */ + if (offset == -1) { + for (split_addr = addr; split_addr < addr + fd_size; split_addr += pmd_pagesize) + write_debugfs(PID_FMT, getpid(), (uint64_t)split_addr, + (uint64_t)split_addr + pagesize, order); + + expected_orders[order] = fd_size / (pagesize << order); + } else { + int times = fd_size / pmd_pagesize; + + for (split_addr = addr; split_addr < addr + fd_size; split_addr += pmd_pagesize) + write_debugfs(PID_FMT_OFFSET, getpid(), (uint64_t)split_addr, + (uint64_t)split_addr + pagesize, order, offset); + + for (i = order + 1; i < pmd_order; i++) + expected_orders[i] = times; + expected_orders[order] = 2 * times; + }
for (i = 0; i < fd_size; i++) if (*(addr + i) != (char)i) { @@ -689,6 +705,14 @@ static void split_thp_in_pagecache_to_order_at(size_t fd_size, goto out; }
+ if (check_after_split_folio_orders(addr, fd_size, pagemap_fd, + kpageflags_fd, expected_orders, + (pmd_order + 1))) { + ksft_print_msg("Unexpected THP split\n"); + err = 1; + goto out; + } + if (!check_huge_file(addr, 0, pmd_pagesize)) { ksft_print_msg("Still FilePmdMapped not split\n"); err = EXIT_FAILURE; @@ -740,9 +764,22 @@ int main(int argc, char **argv)
nr_pages = pmd_pagesize / pagesize; pmd_order = GET_ORDER(nr_pages); + + expected_orders = (int *)malloc(sizeof(int) * (pmd_order + 1)); + if (!expected_orders) + ksft_exit_fail_msg("Fail to allocate memory: %s\n", strerror(errno)); + tests = 2 + (pmd_order - 1) + (2 * pmd_order) + (pmd_order - 1) * 4 + 2; ksft_set_plan(tests);
+ pagemap_fd = open(pagemap_proc, O_RDONLY); + if (pagemap_fd == -1) + ksft_exit_fail_msg("read pagemap: %s\n", strerror(errno)); + + kpageflags_fd = open(kpageflags_proc, O_RDONLY); + if (kpageflags_fd == -1) + ksft_exit_fail_msg("read kpageflags: %s\n", strerror(errno)); + fd_size = 2 * pmd_pagesize;
split_pmd_zero_pages(); @@ -767,6 +804,10 @@ int main(int argc, char **argv) split_thp_in_pagecache_to_order_at(fd_size, fs_loc, i, offset); cleanup_thp_fs(fs_loc, created_tmp);
+ close(pagemap_fd); + close(kpageflags_fd); + free(expected_orders); + ksft_finished();
return 0;