diff options
Diffstat (limited to 'tools/testing/selftests/mm/split_huge_page_test.c')
-rw-r--r-- | tools/testing/selftests/mm/split_huge_page_test.c | 469 |
1 files changed, 366 insertions, 103 deletions
diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 44a3f8a58806..743af3c05190 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -25,6 +25,8 @@ 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" @@ -34,28 +36,225 @@ 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) +const char *pagemap_proc = "/proc/self/pagemap"; +const char *kpageflags_proc = "/proc/kpageflags"; +int pagemap_fd; +int kpageflags_fd; -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; + const uint64_t folio_head_flags = KPF_THP | KPF_COMPOUND_HEAD; + const uint64_t folio_tail_flags = KPF_THP | KPF_COMPOUND_TAIL; + const unsigned long nr_pages = 1UL << order; + unsigned long pfn_head; + uint64_t pfn_flags; + unsigned long pfn; + unsigned long i; + + pfn = pagemap_get_pfn(pagemap_fd, vaddr); + + /* non present page */ + if (pfn == -1UL) + return false; + + if (pageflags_get(pfn, kpageflags_fd, &pfn_flags)) + goto fail; + + /* check for order-0 pages */ + if (!order) { + if (pfn_flags & (folio_head_flags | folio_tail_flags)) + return false; + return true; + } + + /* non THP folio */ + if (!(pfn_flags & KPF_THP)) + return false; + + pfn_head = pfn & ~(nr_pages - 1); + + if (pageflags_get(pfn_head, kpageflags_fd, &pfn_flags)) + goto fail; + + /* head PFN has no compound_head flag set */ + if ((pfn_flags & folio_head_flags) != folio_head_flags) + return false; + + /* check all tail PFN flags */ + for (i = 1; i < nr_pages; i++) { + if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) + goto fail; + if ((pfn_flags & folio_tail_flags) != folio_tail_flags) + 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 + nr_pages, kpageflags_fd, &pfn_flags)) + return true; + + /* If we find another tail page, then the folio is larger. */ + return (pfn_flags & folio_tail_flags) != folio_tail_flags; +fail: + ksft_exit_fail_msg("Failed to get folio info\n"); + return false; +} + +static int vaddr_pageflags_get(char *vaddr, int pagemap_fd, int kpageflags_fd, + uint64_t *flags) +{ + unsigned long pfn; + + pfn = pagemap_get_pfn(pagemap_fd, vaddr); + + /* non-present PFN */ + if (pfn == -1UL) + return 1; + + if (pageflags_get(pfn, kpageflags_fd, flags)) + return -1; + + return 0; +} + +/* + * gather_after_split_folio_orders - scan through [vaddr_start, len) and record + * folio orders + * + * @vaddr_start: start vaddr + * @len: range length + * @pagemap_fd: file descriptor to /proc/<pid>/pagemap + * @kpageflags_fd: file descriptor to /proc/kpageflags + * @orders: output folio order array + * @nr_orders: folio order array size + * + * gather_after_split_folio_orders() scan through [vaddr_start, len) and check + * all folios within the range and record their orders. All order-0 pages will + * 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 after-split folios within that + * range. + * + * Return: 0 - no error, -1 - unhandled cases + */ +static int gather_after_split_folio_orders(char *vaddr_start, size_t len, + int pagemap_fd, int kpageflags_fd, int orders[], int nr_orders) +{ + uint64_t page_flags = 0; + int cur_order = -1; + char *vaddr; + + if (pagemap_fd == -1 || kpageflags_fd == -1) + return -1; + if (!orders) + return -1; + if (nr_orders <= 0) + return -1; + + for (vaddr = vaddr_start; vaddr < vaddr_start + len;) { + char *next_folio_vaddr; + int status; + + status = vaddr_pageflags_get(vaddr, pagemap_fd, kpageflags_fd, + &page_flags); + if (status < 0) + return -1; + + /* skip non present vaddr */ + if (status == 1) { + vaddr += psize(); + continue; + } - if (pagemap_file) { - pread(pagemap_file, &paddr, sizeof(paddr), - ((long)vaddr >> pageshift) * sizeof(paddr)); + /* all order-0 pages with possible false postive (non folio) */ + if (!(page_flags & (KPF_COMPOUND_HEAD | KPF_COMPOUND_TAIL))) { + orders[0]++; + vaddr += psize(); + continue; + } - if (kpageflags_file) { - pread(kpageflags_file, &page_flags, sizeof(page_flags), - (paddr & PFN_MASK) * sizeof(page_flags)); + /* skip non thp compound pages */ + if (!(page_flags & KPF_THP)) { + vaddr += psize(); + continue; + } - return !!(page_flags & KPF_THP); + /* vpn points to part of a THP at this point */ + if (page_flags & KPF_COMPOUND_HEAD) + cur_order = 1; + else { + vaddr += psize(); + continue; } + + next_folio_vaddr = vaddr + (1UL << (cur_order + pshift())); + + if (next_folio_vaddr >= vaddr_start + len) + break; + + while ((status = vaddr_pageflags_get(next_folio_vaddr, + pagemap_fd, kpageflags_fd, + &page_flags)) >= 0) { + /* + * non present vaddr, next compound head page, or + * order-0 page + */ + if (status == 1 || + (page_flags & KPF_COMPOUND_HEAD) || + !(page_flags & (KPF_COMPOUND_HEAD | KPF_COMPOUND_TAIL))) { + if (cur_order < nr_orders) { + orders[cur_order]++; + cur_order = -1; + vaddr = next_folio_vaddr; + } + break; + } + + cur_order++; + next_folio_vaddr = vaddr + (1UL << (cur_order + pshift())); + } + + if (status < 0) + return status; } + if (cur_order > 0 && cur_order < nr_orders) + orders[cur_order]++; return 0; } +static int check_after_split_folio_orders(char *vaddr_start, size_t len, + int pagemap_fd, int kpageflags_fd, int orders[], int nr_orders) +{ + int *vaddr_orders; + int status; + int i; + + vaddr_orders = (int *)malloc(sizeof(int) * nr_orders); + + if (!vaddr_orders) + ksft_exit_fail_msg("Cannot allocate memory for vaddr_orders"); + + memset(vaddr_orders, 0, sizeof(int) * nr_orders); + status = gather_after_split_folio_orders(vaddr_start, len, pagemap_fd, + kpageflags_fd, vaddr_orders, nr_orders); + if (status) + ksft_exit_fail_msg("gather folio info failed\n"); + + for (i = 0; i < nr_orders; i++) + if (vaddr_orders[i] != orders[i]) { + ksft_print_msg("order %d: expected: %d got %d\n", i, + orders[i], vaddr_orders[i]); + status = -1; + } + + free(vaddr_orders); + return status; +} + static void write_file(const char *path, const char *buf, size_t buflen) { int fd; @@ -111,7 +310,7 @@ static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hp unsigned long rss_anon_before, rss_anon_after; size_t i; - if (!check_huge_anon(one_page, 4, pmd_pagesize)) + if (!check_huge_anon(one_page, nr_hpages, pmd_pagesize)) ksft_exit_fail_msg("No THP is allocated\n"); rss_anon_before = rss_anon(); @@ -135,7 +334,7 @@ static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hp rss_anon_before, rss_anon_after); } -void split_pmd_zero_pages(void) +static void split_pmd_zero_pages(void) { char *one_page; int nr_hpages = 4; @@ -147,7 +346,7 @@ void split_pmd_zero_pages(void) free(one_page); } -void split_pmd_thp_to_order(int order) +static void split_pmd_thp_to_order(int order) { char *one_page; size_t len = 4 * pmd_pagesize; @@ -173,6 +372,13 @@ 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"); @@ -181,90 +387,97 @@ void split_pmd_thp_to_order(int order) free(one_page); } -void split_pte_mapped_thp(void) +static void split_pte_mapped_thp(void) { - char *one_page, *pte_mapped, *pte_mapped2; - size_t len = 4 * pmd_pagesize; - uint64_t thp_size; + const size_t nr_thps = 4; + const size_t thp_area_size = nr_thps * pmd_pagesize; + const size_t page_area_size = nr_thps * pagesize; + char *thp_area, *tmp, *page_area = MAP_FAILED; 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)); + thp_area = mmap((void *)(1UL << 30), thp_area_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (thp_area == MAP_FAILED) { + ksft_test_result_fail("Fail to allocate memory: %s\n", strerror(errno)); + return; + } - pagemap_fd = open(pagemap_proc, O_RDONLY); - if (pagemap_fd == -1) - ksft_exit_fail_msg("read pagemap: %s\n", strerror(errno)); + madvise(thp_area, thp_area_size, MADV_HUGEPAGE); - kpageflags_fd = open(kpageflags_proc, O_RDONLY); - if (kpageflags_fd == -1) - ksft_exit_fail_msg("read kpageflags: %s\n", strerror(errno)); + for (i = 0; i < thp_area_size; i++) + thp_area[i] = (char)i; - one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, - MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); - if (one_page == MAP_FAILED) - ksft_exit_fail_msg("Fail to allocate memory: %s\n", strerror(errno)); + if (!check_huge_anon(thp_area, nr_thps, pmd_pagesize)) { + ksft_test_result_skip("Not all THPs allocated\n"); + goto out; + } - madvise(one_page, len, MADV_HUGEPAGE); + /* + * To challenge spitting code, we will mremap a single page of each + * THP (page[i] of thp[i]) in the thp_area into page_area. This will + * replace the PMD mappings in the thp_area by PTE mappings first, + * but leaving the THP unsplit, to then create a page-sized hole in + * the thp_area. + * We will then manually trigger splitting of all THPs through the + * single mremap'ed pages of each THP in the page_area. + */ + page_area = mmap(NULL, page_area_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (page_area == MAP_FAILED) { + ksft_test_result_fail("Fail to allocate memory: %s\n", strerror(errno)); + goto out; + } - for (i = 0; i < len; i++) - one_page[i] = (char)i; + for (i = 0; i < nr_thps; i++) { + tmp = mremap(thp_area + pmd_pagesize * i + pagesize * i, + pagesize, pagesize, MREMAP_MAYMOVE|MREMAP_FIXED, + page_area + pagesize * i); + if (tmp != MAP_FAILED) + continue; + ksft_test_result_fail("mremap failed: %s\n", strerror(errno)); + goto out; + } - if (!check_huge_anon(one_page, 4, pmd_pagesize)) - ksft_exit_fail_msg("No THP is allocated\n"); + /* + * Verify that our THPs were not split yet. Note that + * check_huge_anon() cannot be used as it checks for PMD mappings. + */ + for (i = 0; i < nr_thps; i++) { + if (is_backed_by_folio(page_area + i * pagesize, pmd_order, + pagemap_fd, kpageflags_fd)) + continue; + ksft_test_result_fail("THP %zu missing after mremap\n", i); + goto out; + } - /* remap the first pagesize of first THP */ - pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); - - /* remap the Nth pagesize of Nth THP */ - for (i = 1; i < 4; i++) { - pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i, - pagesize, pagesize, - MREMAP_MAYMOVE|MREMAP_FIXED, - pte_mapped + pagesize * i); - if (pte_mapped2 == MAP_FAILED) - ksft_exit_fail_msg("mremap failed: %s\n", strerror(errno)); - } - - /* smap does not show THPs after mremap, use kpageflags instead */ - 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)) - thp_size++; - - if (thp_size != 4) - ksft_exit_fail_msg("Some THPs are missing during mremap\n"); - - /* split all remapped THPs */ - write_debugfs(PID_FMT, getpid(), (uint64_t)pte_mapped, - (uint64_t)pte_mapped + pagesize * 4, 0); - - /* smap does not show THPs after mremap, use kpageflags instead */ - thp_size = 0; - for (i = 0; i < pagesize * 4; i++) { - if (pte_mapped[i] != (char)i) - ksft_exit_fail_msg("%ld byte corrupted\n", i); + /* Split all THPs through the remapped pages. */ + write_debugfs(PID_FMT, getpid(), (uint64_t)page_area, + (uint64_t)page_area + page_area_size, 0); - if (i % pagesize == 0 && - is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) - thp_size++; + /* Corruption during mremap or split? */ + for (i = 0; i < page_area_size; i++) { + if (page_area[i] == (char)i) + continue; + ksft_test_result_fail("%zu byte corrupted\n", i); + goto out; } - if (thp_size) - ksft_exit_fail_msg("Still %ld THPs not split\n", thp_size); + /* Split failed? */ + for (i = 0; i < nr_thps; i++) { + if (is_backed_by_folio(page_area + i * pagesize, 0, + pagemap_fd, kpageflags_fd)) + continue; + ksft_test_result_fail("THP %zu not split\n", i); + } ksft_test_result_pass("Split PTE-mapped huge pages successful\n"); - munmap(one_page, len); - close(pagemap_fd); - close(kpageflags_fd); +out: + munmap(thp_area, thp_area_size); + if (page_area != MAP_FAILED) + munmap(page_area, page_area_size); } -void split_file_backed_thp(int order) +static void split_file_backed_thp(int order) { int status; int fd; @@ -297,7 +510,7 @@ void split_file_backed_thp(int order) status = snprintf(testfile, INPUT_MAX, "%s/thp_file", tmpfs_loc); if (status >= INPUT_MAX) { - ksft_exit_fail_msg("Fail to create file-backed THP split testing file\n"); + ksft_print_msg("Fail to create file-backed THP split testing file\n"); goto cleanup; } @@ -366,7 +579,7 @@ out: ksft_exit_fail_msg("Error occurred\n"); } -bool prepare_thp_fs(const char *xfs_path, char *thp_fs_template, +static bool prepare_thp_fs(const char *xfs_path, char *thp_fs_template, const char **thp_fs_loc) { if (xfs_path) { @@ -382,7 +595,7 @@ bool prepare_thp_fs(const char *xfs_path, char *thp_fs_template, return true; } -void cleanup_thp_fs(const char *thp_fs_loc, bool created_tmp) +static void cleanup_thp_fs(const char *thp_fs_loc, bool created_tmp) { int status; @@ -395,8 +608,8 @@ void cleanup_thp_fs(const char *thp_fs_loc, bool created_tmp) strerror(errno)); } -int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, int *fd, - char **addr) +static int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, + int *fd, char **addr) { size_t i; unsigned char buf[1024]; @@ -462,10 +675,11 @@ err_out_unlink: return -1; } -void split_thp_in_pagecache_to_order_at(size_t fd_size, const char *fs_loc, - int order, int offset) +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]; @@ -479,14 +693,33 @@ void split_thp_in_pagecache_to_order_at(size_t fd_size, const char *fs_loc, 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) { @@ -495,6 +728,14 @@ void split_thp_in_pagecache_to_order_at(size_t fd_size, const char *fs_loc, 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; @@ -525,6 +766,8 @@ int main(int argc, char **argv) const char *fs_loc; bool created_tmp; int offset; + unsigned int nr_pages; + unsigned int tests; ksft_print_header(); @@ -536,38 +779,58 @@ int main(int argc, char **argv) if (argc > 1) optional_xfs_path = argv[1]; - ksft_set_plan(1+8+1+9+9+8*4+2); - pagesize = getpagesize(); pageshift = ffs(pagesize) - 1; pmd_pagesize = read_pmd_pagesize(); if (!pmd_pagesize) ksft_exit_fail_msg("Reading PMD pagesize failed\n"); + nr_pages = pmd_pagesize / pagesize; + pmd_order = sz2ord(pmd_pagesize, pagesize); + + 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(); - for (i = 0; i < 9; 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 < 9; 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 = 8; 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 < 9; i++) + for (i = 0; i < pmd_order; i++) for (offset = 0; - offset < pmd_pagesize / pagesize; - offset += MAX(pmd_pagesize / pagesize / 4, 1 << i)) + offset < nr_pages; + offset += MAX(nr_pages / 4, 1 << i)) 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; |