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X-FangMail-Envelope: 1672363132/4NjnTS10zfz501Qj/63AE3C7C.000/10.5.228.133/[10.5.228.133]/mse-fl2.zte.com.cn/ X-Fangmail-Anti-Spam-Filtered: true X-Fangmail-MID-QID: 63AE3C7C.000/4NjnTS10zfz501Qj X-Rspam-User: X-Rspamd-Queue-Id: C5FF440007 X-Rspamd-Server: rspam01 X-Stat-Signature: xh4sfx5susyq911o1cyq3i1xjj633w4k X-HE-Tag: 1672363134-783814 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: xu xin Add a function test_unmerge_zero_page() to test the functionality on unsharing and counting ksm-placed zero pages and counting of this patch series. test_unmerge_zero_page() actually contains three subjct test objects: 1) whether the count of ksm zero page can react correctly to cow (copy on write); 2) whether the count of ksm zero page can react correctly to unmerge; 3) whether ksm zero pages are really unmerged. Signed-off-by: xu xin Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Xuexin Jiang Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang v4->v5: fix error of "} while (end_scans < start_scans + 20);" to "} while (end_scans < start_scans + 2);" in wait_two_full_scans(). --- tools/testing/selftests/vm/ksm_functional_tests.c | 103 +++++++++++++++++++++- 1 file changed, 99 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/vm/ksm_functional_tests.c b/tools/testing/selftests/vm/ksm_functional_tests.c index b11b7e5115dc..b792798a54c4 100644 --- a/tools/testing/selftests/vm/ksm_functional_tests.c +++ b/tools/testing/selftests/vm/ksm_functional_tests.c @@ -27,6 +27,8 @@ static int ksm_fd; static int ksm_full_scans_fd; +static int ksm_zero_pages_fd; +static int ksm_use_zero_pages_fd; static int pagemap_fd; static size_t pagesize; @@ -57,6 +59,22 @@ static bool range_maps_duplicates(char *addr, unsigned long size) return false; } +static bool check_ksm_zero_pages_count(unsigned long zero_size) +{ + unsigned long pages_expected = zero_size / (4 * KiB); + char buf[20]; + ssize_t read_size; + unsigned long ksm_zero_pages; + + read_size = pread(ksm_zero_pages_fd, buf, sizeof(buf) - 1, 0); + if (read_size < 0) + return -errno; + buf[read_size] = 0; + ksm_zero_pages = strtol(buf, NULL, 10); + + return ksm_zero_pages == pages_expected; +} + static long ksm_get_full_scans(void) { char buf[10]; @@ -70,15 +88,12 @@ static long ksm_get_full_scans(void) return strtol(buf, NULL, 10); } -static int ksm_merge(void) +static int wait_two_full_scans(void) { long start_scans, end_scans; - /* Wait for two full scans such that any possible merging happened. */ start_scans = ksm_get_full_scans(); if (start_scans < 0) - return start_scans; - if (write(ksm_fd, "1", 1) != 1) return -errno; do { end_scans = ksm_get_full_scans(); @@ -89,6 +104,34 @@ static int ksm_merge(void) return 0; } +static inline int ksm_merge(void) +{ + /* Wait for two full scans such that any possible merging happened. */ + if (write(ksm_fd, "1", 1) != 1) + return -errno; + return wait_two_full_scans(); +} + +static inline int make_cow(char *map, char val, unsigned long size) +{ + + memset(map, val, size); + return wait_two_full_scans(); +} + +static int unmerge_zero_page(char *start, unsigned long size) +{ + int ret; + + ret = madvise(start, size, MADV_UNMERGEABLE); + if (ret) { + ksft_test_result_fail("MADV_UNMERGEABLE failed\n"); + return ret; + } + + return wait_two_full_scans(); +} + static char *mmap_and_merge_range(char val, unsigned long size) { char *map; @@ -146,6 +189,56 @@ static void test_unmerge(void) munmap(map, size); } +static void test_unmerge_zero_pages(void) +{ + const unsigned int size = 2 * MiB; + char *map; + + ksft_print_msg("[RUN] %s\n", __func__); + + /* Confirm the interfaces*/ + ksm_zero_pages_fd = open("/sys/kernel/mm/ksm/zero_pages_sharing", O_RDONLY); + if (ksm_zero_pages_fd < 0) { + ksft_test_result_skip("open(\"/sys/kernel/mm/ksm/zero_pages_sharing\") failed\n"); + return; + } + ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR); + if (ksm_use_zero_pages_fd < 0) { + ksft_test_result_skip("open \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); + return; + } + if (write(ksm_use_zero_pages_fd, "1", 1) != 1) { + ksft_test_result_skip("write \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); + return; + } + + /* Mmap zero pages*/ + map = mmap_and_merge_range(0x00, size); + + /* Case 1: make Writing on ksm zero pages (COW) */ + if (make_cow(map, 0xcf, size / 2)) { + ksft_test_result_fail("COW failed\n"); + goto unmap; + } + ksft_test_result(check_ksm_zero_pages_count(size / 2), + "zero page count react to cow\n"); + + /* Case 2: Call madvise(xxx, MADV_UNMERGEABLE)*/ + if (unmerge_zero_page(map + size / 2, size / 4)) { + ksft_test_result_fail("unmerge_zero_page failed\n"); + goto unmap; + } + ksft_test_result(check_ksm_zero_pages_count(size / 4), + "zero page count react to unmerge\n"); + + /*Check if ksm pages are really unmerged */ + ksft_test_result(!range_maps_duplicates(map + size / 2, size / 4), + "KSM zero pages were unmerged\n"); + +unmap: + munmap(map, size); +} + static void test_unmerge_discarded(void) { const unsigned int size = 2 * MiB; @@ -261,11 +354,13 @@ int main(int argc, char **argv) ksm_full_scans_fd = open("/sys/kernel/mm/ksm/full_scans", O_RDONLY); if (ksm_full_scans_fd < 0) ksft_exit_skip("open(\"/sys/kernel/mm/ksm/full_scans\") failed\n"); + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); if (pagemap_fd < 0) ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n"); test_unmerge(); + test_unmerge_zero_pages(); test_unmerge_discarded(); #ifdef __NR_userfaultfd test_unmerge_uffd_wp(); -- 2.15.2