diff options
Diffstat (limited to 'tools/testing/selftests/mm/soft-dirty.c')
| -rw-r--r-- | tools/testing/selftests/mm/soft-dirty.c | 348 |
1 files changed, 348 insertions, 0 deletions
diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selftests/mm/soft-dirty.c new file mode 100644 index 000000000000..59c0dbe99a9b --- /dev/null +++ b/tools/testing/selftests/mm/soft-dirty.c @@ -0,0 +1,348 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <stdio.h> +#include <string.h> +#include <stdbool.h> +#include <fcntl.h> +#include <stdint.h> +#include <malloc.h> +#include <sys/mman.h> + +#include "kselftest.h" +#include "vm_util.h" +#include "thp_settings.h" + +#define PAGEMAP_FILE_PATH "/proc/self/pagemap" +#define TEST_ITERATIONS 10000 + +static void test_simple(int pagemap_fd, int pagesize) +{ + int i; + char *map; + + map = aligned_alloc(pagesize, pagesize); + if (!map) + ksft_exit_fail_msg("mmap failed\n"); + + clear_softdirty(); + + for (i = 0 ; i < TEST_ITERATIONS; i++) { + if (pagemap_is_softdirty(pagemap_fd, map) == 1) { + ksft_print_msg("dirty bit was 1, but should be 0 (i=%d)\n", i); + break; + } + + clear_softdirty(); + // Write something to the page to get the dirty bit enabled on the page + map[0]++; + + if (pagemap_is_softdirty(pagemap_fd, map) == 0) { + ksft_print_msg("dirty bit was 0, but should be 1 (i=%d)\n", i); + break; + } + + clear_softdirty(); + } + free(map); + + ksft_test_result(i == TEST_ITERATIONS, "Test %s\n", __func__); +} + +static void test_vma_reuse(int pagemap_fd, int pagesize) +{ + char *map, *map2; + + map = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0); + if (map == MAP_FAILED) + ksft_exit_fail_msg("mmap failed"); + + // The kernel always marks new regions as soft dirty + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s dirty bit of allocated page\n", __func__); + + clear_softdirty(); + munmap(map, pagesize); + + map2 = mmap(NULL, pagesize, (PROT_READ | PROT_WRITE), (MAP_PRIVATE | MAP_ANON), -1, 0); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mmap failed"); + + // Dirty bit is set for new regions even if they are reused + if (map == map2) + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1, + "Test %s dirty bit of reused address page\n", __func__); + else + ksft_test_result_skip("Test %s dirty bit of reused address page\n", __func__); + + munmap(map2, pagesize); +} + +static void test_hugepage(int pagemap_fd, int pagesize) +{ + char *map; + int i, ret; + + if (!thp_is_enabled()) { + ksft_test_result_skip("Transparent Hugepages not available\n"); + return; + } + + size_t hpage_len = read_pmd_pagesize(); + if (!hpage_len) + ksft_exit_fail_msg("Reading PMD pagesize failed"); + + map = memalign(hpage_len, hpage_len); + if (!map) + ksft_exit_fail_msg("memalign failed\n"); + + ret = madvise(map, hpage_len, MADV_HUGEPAGE); + if (ret) + ksft_exit_fail_msg("madvise failed %d\n", ret); + + for (i = 0; i < hpage_len; i++) + map[i] = (char)i; + + if (check_huge_anon(map, 1, hpage_len)) { + ksft_test_result_pass("Test %s huge page allocation\n", __func__); + + clear_softdirty(); + for (i = 0 ; i < TEST_ITERATIONS ; i++) { + if (pagemap_is_softdirty(pagemap_fd, map) == 1) { + ksft_print_msg("dirty bit was 1, but should be 0 (i=%d)\n", i); + break; + } + + clear_softdirty(); + // Write something to the page to get the dirty bit enabled on the page + map[0]++; + + if (pagemap_is_softdirty(pagemap_fd, map) == 0) { + ksft_print_msg("dirty bit was 0, but should be 1 (i=%d)\n", i); + break; + } + clear_softdirty(); + } + + ksft_test_result(i == TEST_ITERATIONS, "Test %s huge page dirty bit\n", __func__); + } else { + // hugepage allocation failed. skip these tests + ksft_test_result_skip("Test %s huge page allocation\n", __func__); + ksft_test_result_skip("Test %s huge page dirty bit\n", __func__); + } + free(map); +} + +static void test_mprotect(int pagemap_fd, int pagesize, bool anon) +{ + const char *type[] = {"file", "anon"}; + const char *fname = "./soft-dirty-test-file"; + int test_fd = 0; + char *map; + + if (anon) { + map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE, + MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); + if (!map) + ksft_exit_fail_msg("anon mmap failed\n"); + } else { + test_fd = open(fname, O_RDWR | O_CREAT, 0664); + if (test_fd < 0) { + ksft_test_result_skip("Test %s open() file failed\n", __func__); + return; + } + unlink(fname); + ftruncate(test_fd, pagesize); + map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE, + MAP_SHARED, test_fd, 0); + if (!map) + ksft_exit_fail_msg("file mmap failed\n"); + } + + *map = 1; + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s-%s dirty bit of new written page\n", + __func__, type[anon]); + clear_softdirty(); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0, + "Test %s-%s soft-dirty clear after clear_refs\n", + __func__, type[anon]); + mprotect(map, pagesize, PROT_READ); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0, + "Test %s-%s soft-dirty clear after marking RO\n", + __func__, type[anon]); + mprotect(map, pagesize, PROT_READ|PROT_WRITE); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0, + "Test %s-%s soft-dirty clear after marking RW\n", + __func__, type[anon]); + *map = 2; + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s-%s soft-dirty after rewritten\n", + __func__, type[anon]); + + munmap(map, pagesize); + + if (!anon) + close(test_fd); +} + +static void test_merge(int pagemap_fd, int pagesize) +{ + char *reserved, *map, *map2; + + /* + * Reserve space for tests: + * + * ---padding to --- + * | avoid adj. | + * v merge v + * |---|---|---|---|---| + * | | 1 | 2 | 3 | | + * |---|---|---|---|---| + */ + reserved = mmap(NULL, 5 * pagesize, PROT_NONE, + MAP_ANON | MAP_PRIVATE, -1, 0); + if (reserved == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + munmap(reserved, 4 * pagesize); + + /* + * Establish initial VMA: + * + * S/D + * |---|---|---|---|---| + * | | 1 | | | | + * |---|---|---|---|---| + */ + map = mmap(&reserved[pagesize], pagesize, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* This will clear VM_SOFTDIRTY too. */ + clear_softdirty(); + + /* + * Now place a new mapping which will be marked VM_SOFTDIRTY. Away from + * map: + * + * - S/D + * |---|---|---|---|---| + * | | 1 | | 2 | | + * |---|---|---|---|---| + */ + map2 = mmap(&reserved[3 * pagesize], pagesize, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* + * Now remap it immediately adjacent to map, if the merge correctly + * propagates VM_SOFTDIRTY, we should then observe the VMA as a whole + * being marked soft-dirty: + * + * merge + * S/D + * |---|-------|---|---| + * | | 1 | | | + * |---|-------|---|---| + */ + map2 = mremap(map2, pagesize, pagesize, MREMAP_FIXED | MREMAP_MAYMOVE, + &reserved[2 * pagesize]); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mremap failed\n"); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s-anon soft-dirty after remap merge 1st pg\n", + __func__); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1, + "Test %s-anon soft-dirty after remap merge 2nd pg\n", + __func__); + + munmap(map, 2 * pagesize); + + /* + * Now establish another VMA: + * + * S/D + * |---|---|---|---|---| + * | | 1 | | | | + * |---|---|---|---|---| + */ + map = mmap(&reserved[pagesize], pagesize, PROT_READ | PROT_WRITE, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* Clear VM_SOFTDIRTY... */ + clear_softdirty(); + /* ...and establish incompatible adjacent VMA: + * + * - S/D + * |---|---|---|---|---| + * | | 1 | 2 | | | + * |---|---|---|---|---| + */ + map2 = mmap(&reserved[2 * pagesize], pagesize, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0); + if (map2 == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* + * Now mprotect() VMA 1 so it's compatible with 2 and therefore merges: + * + * merge + * S/D + * |---|-------|---|---| + * | | 1 | | | + * |---|-------|---|---| + */ + if (mprotect(map, pagesize, PROT_READ | PROT_WRITE | PROT_EXEC)) + ksft_exit_fail_msg("mprotect failed\n"); + + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1, + "Test %s-anon soft-dirty after mprotect merge 1st pg\n", + __func__); + ksft_test_result(pagemap_is_softdirty(pagemap_fd, map2) == 1, + "Test %s-anon soft-dirty after mprotect merge 2nd pg\n", + __func__); + + munmap(map, 2 * pagesize); +} + +static void test_mprotect_anon(int pagemap_fd, int pagesize) +{ + test_mprotect(pagemap_fd, pagesize, true); +} + +static void test_mprotect_file(int pagemap_fd, int pagesize) +{ + test_mprotect(pagemap_fd, pagesize, false); +} + +int main(int argc, char **argv) +{ + int pagemap_fd; + int pagesize; + + ksft_print_header(); + + if (!softdirty_supported()) + ksft_exit_skip("soft-dirty is not support\n"); + + ksft_set_plan(19); + pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY); + if (pagemap_fd < 0) + ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH); + + pagesize = getpagesize(); + + test_simple(pagemap_fd, pagesize); + test_vma_reuse(pagemap_fd, pagesize); + test_hugepage(pagemap_fd, pagesize); + test_mprotect_anon(pagemap_fd, pagesize); + test_mprotect_file(pagemap_fd, pagesize); + test_merge(pagemap_fd, pagesize); + + close(pagemap_fd); + + ksft_finished(); +} |