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X-FangMail-Envelope: 1672020532/4NgLn06Lxpz8R041/63A90234.000/10.5.228.132/[10.5.228.132]/mse-fl1.zte.com.cn/ X-Fangmail-Anti-Spam-Filtered: true X-Fangmail-MID-QID: 63A90234.000/4NgLn06Lxpz8R041 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1508D20002 X-Stat-Signature: w7e59poyn1ufx5jx14kih1ujtud4nfta X-HE-Tag: 1672020536-929066 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 --- tools/testing/selftests/vm/ksm_functional_tests.c | 105 ++++++++++++++++++++-- 1 file changed, 100 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/vm/ksm_functional_tests.c b/tools/testing/selftests/vm/ksm_functional_tests.c index b11b7e5115dc..2c50c14d42db 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]; @@ -70,25 +88,50 @@ 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(); if (end_scans < 0) return end_scans; - } while (end_scans < start_scans + 2); + } while (end_scans < start_scans + 20); 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