Messages in this thread Patch in this message | | | From | Yang Yang <> | Subject | [PATCH v7 6/6] selftest: add a testcase of ksm zero pages | Date | Thu, 13 Apr 2023 13:58:36 +0800 |
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From: xu xin <xu.xin16@zte.com.cn>
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 pages can update correctly after merging; (2) whether the count of ksm zero pages can update correctly after unmerging; (3) whether ksm zero pages are really unmerged.
Signed-off-by: xu xin <xu.xin16@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> --- tools/testing/selftests/mm/ksm_functional_tests.c | 75 +++++++++++++++++++++++ 1 file changed, 75 insertions(+)
diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c index d8b5b4930412..11f8e4726607 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/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 +59,21 @@ static bool range_maps_duplicates(char *addr, unsigned long size) return false; } +static long get_ksm_zero_pages(void) +{ + 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; +} + static long ksm_get_full_scans(void) { char buf[10]; @@ -146,6 +163,61 @@ static void test_unmerge(void) munmap(map, size); } +static inline unsigned long expected_ksm_pages(unsigned long mergeable_size) +{ + return mergeable_size / pagesize; +} + +static void test_unmerge_zero_pages(void) +{ + const unsigned int size = 2 * MiB; + char *map; + unsigned long pages_expected; + + ksft_print_msg("[RUN] %s\n", __func__); + + /* Confirm the interfaces*/ + if (ksm_zero_pages_fd < 0) { + ksft_test_result_skip("open(\"/sys/kernel/mm/ksm/ksm_zero_pages\") failed\n"); + return; + } + 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); + if (map == MAP_FAILED) + return; + + /* Check if ksm_zero_pages can be update correctly after merging */ + pages_expected = expected_ksm_pages(size); + ksft_test_result(pages_expected == get_ksm_zero_pages(), + "The count zero_page_sharing was updated after merging\n"); + + /* try to unmerge half of the region */ + if (madvise(map, size / 2, MADV_UNMERGEABLE)) { + ksft_test_result_fail("MADV_UNMERGEABLE failed\n"); + goto unmap; + } + + /* Check if ksm_zero_pages can be update correctly after unmerging */ + pages_expected = expected_ksm_pages(size / 2); + ksft_test_result(pages_expected == get_ksm_zero_pages(), + "The count zero_page_sharing was updated after unmerging\n"); + + /* Check if ksm zero pages are really unmerged */ + ksft_test_result(!range_maps_duplicates(map, size / 2), + "KSM zero pages were unmerged\n"); +unmap: + munmap(map, size); +} + static void test_unmerge_discarded(void) { const unsigned int size = 2 * MiB; @@ -264,8 +336,11 @@ int main(int argc, char **argv) pagemap_fd = open("/proc/self/pagemap", O_RDONLY); if (pagemap_fd < 0) ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n"); + ksm_zero_pages_fd = open("/sys/kernel/mm/ksm/ksm_zero_pages", O_RDONLY); + ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR); test_unmerge(); + test_unmerge_zero_pages(); test_unmerge_discarded(); #ifdef __NR_userfaultfd test_unmerge_uffd_wp(); -- 2.15.2
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