and rename it to is_backed_by_folio(). is_backed_by_folio() checks if the given vaddr is backed a folio with a given order. It does so by: 1. getting the pfn of the vaddr; 2. checking kpageflags of the pfn; if order is greater than 0: 3. checking kpageflags of the head pfn; 4. checking kpageflags of all tail pfns. pmd_order is added to split_huge_page_test.c and replaces max_order. Signed-off-by: Zi Yan Reviewed-by: Wei Yang Reviewed-by: wang lian --- .../selftests/mm/split_huge_page_test.c | 88 ++++++++++++++----- tools/testing/selftests/mm/vm_util.c | 13 +++ tools/testing/selftests/mm/vm_util.h | 4 + 3 files changed, 81 insertions(+), 24 deletions(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 089e146efeab..56d1eaf9a860 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -25,6 +25,7 @@ uint64_t pagesize; unsigned int pageshift; uint64_t pmd_pagesize; +unsigned int pmd_order; #define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" #define SMAP_PATH "/proc/self/smaps" @@ -34,26 +35,66 @@ uint64_t pmd_pagesize; #define PID_FMT_OFFSET "%d,0x%lx,0x%lx,%d,%d" #define PATH_FMT "%s,0x%lx,0x%lx,%d" -#define PFN_MASK ((1UL<<55)-1) -#define KPF_THP (1UL<<22) - -static int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) +static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, + int kpageflags_fd) { - uint64_t paddr; - uint64_t page_flags; + unsigned long pfn_head; + uint64_t pfn_flags; + unsigned long pfn; + unsigned long i; - if (pagemap_file) { - pread(pagemap_file, &paddr, sizeof(paddr), - ((long)vaddr >> pageshift) * sizeof(paddr)); + pfn = pagemap_get_pfn(pagemap_fd, vaddr); - if (kpageflags_file) { - pread(kpageflags_file, &page_flags, sizeof(page_flags), - (paddr & PFN_MASK) * sizeof(page_flags)); + /* non present page */ + if (pfn == -1UL) + return false; - return !!(page_flags & KPF_THP); - } + if (pageflags_get(pfn, kpageflags_fd, &pfn_flags)) + goto fail; + + /* check for order-0 pages */ + if (!order) { + if (pfn_flags & (KPF_THP | KPF_COMPOUND_HEAD | KPF_COMPOUND_TAIL)) + return false; + return true; } - return 0; + + /* non THP folio */ + if (!(pfn_flags & KPF_THP)) + return false; + + pfn_head = pfn & ~((1 << order) - 1); + + if (pageflags_get(pfn_head, kpageflags_fd, &pfn_flags)) + goto fail; + + /* head PFN has no compound_head flag set */ + if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_HEAD))) + return false; + + /* check all tail PFN flags */ + for (i = 1; i < 1UL << order; i++) { + if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) + goto fail; + if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL))) + return false; + } + + /* + * check the PFN after this folio, but if its flags cannot be obtained, + * assume this folio has the expected order + */ + if (pageflags_get(pfn_head + (1UL << order), kpageflags_fd, &pfn_flags)) + return true; + + /* this folio is bigger than the given order */ + if (pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL)) + return false; + + return true; +fail: + ksft_exit_fail_msg("Failed to get folio info\n"); + return false; } static void write_file(const char *path, const char *buf, size_t buflen) @@ -234,7 +275,7 @@ static void split_pte_mapped_thp(void) thp_size = 0; for (i = 0; i < pagesize * 4; i++) if (i % pagesize == 0 && - is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd, kpageflags_fd)) thp_size++; if (thp_size != 4) @@ -251,7 +292,7 @@ static void split_pte_mapped_thp(void) ksft_exit_fail_msg("%ld byte corrupted\n", i); if (i % pagesize == 0 && - is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + !is_backed_by_folio(&pte_mapped[i], 0, pagemap_fd, kpageflags_fd)) thp_size++; } @@ -523,7 +564,6 @@ int main(int argc, char **argv) const char *fs_loc; bool created_tmp; int offset; - unsigned int max_order; unsigned int nr_pages; unsigned int tests; @@ -544,28 +584,28 @@ int main(int argc, char **argv) ksft_exit_fail_msg("Reading PMD pagesize failed\n"); nr_pages = pmd_pagesize / pagesize; - max_order = sz2ord(pmd_pagesize, pagesize); - tests = 2 + (max_order - 1) + (2 * max_order) + (max_order - 1) * 4 + 2; + pmd_order = sz2ord(pmd_pagesize, pagesize); + tests = 2 + (pmd_order - 1) + (2 * pmd_order) + (pmd_order - 1) * 4 + 2; ksft_set_plan(tests); fd_size = 2 * pmd_pagesize; split_pmd_zero_pages(); - for (i = 0; i < max_order; i++) + for (i = 0; i < pmd_order; i++) if (i != 1) split_pmd_thp_to_order(i); split_pte_mapped_thp(); - for (i = 0; i < max_order; i++) + for (i = 0; i < pmd_order; i++) split_file_backed_thp(i); created_tmp = prepare_thp_fs(optional_xfs_path, fs_loc_template, &fs_loc); - for (i = max_order - 1; i >= 0; i--) + for (i = pmd_order - 1; i >= 0; i--) split_thp_in_pagecache_to_order_at(fd_size, fs_loc, i, -1); - for (i = 0; i < max_order; i++) + for (i = 0; i < pmd_order; i++) for (offset = 0; offset < nr_pages; offset += MAX(nr_pages / 4, 1 << i)) diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 6a239aa413e2..741fc129313d 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -338,6 +338,19 @@ int detect_hugetlb_page_sizes(size_t sizes[], int max) return count; } +int pageflags_get(unsigned long pfn, int kpageflags_fd, uint64_t *flags) +{ + size_t count; + + count = pread(kpageflags_fd, flags, sizeof(*flags), + pfn * sizeof(*flags)); + + if (count != sizeof(*flags)) + return -1; + + return 0; +} + /* If `ioctls' non-NULL, the allowed ioctls will be returned into the var */ int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor, uint64_t *ioctls) diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h index 3da56feeb944..ab8722f482ae 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -18,6 +18,9 @@ #define PM_SWAP BIT_ULL(62) #define PM_PRESENT BIT_ULL(63) +#define KPF_COMPOUND_HEAD BIT_ULL(15) +#define KPF_COMPOUND_TAIL BIT_ULL(16) +#define KPF_THP BIT_ULL(22) /* * Ignore the checkpatch warning, we must read from x but don't want to do * anything with it in order to trigger a read page fault. We therefore must use @@ -85,6 +88,7 @@ bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size); int64_t allocate_transhuge(void *ptr, int pagemap_fd); unsigned long default_huge_page_size(void); int detect_hugetlb_page_sizes(size_t sizes[], int max); +int pageflags_get(unsigned long pfn, int kpageflags_fd, uint64_t *flags); int uffd_register(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor); -- 2.50.1