From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AB25C3DA7A for ; Fri, 30 Dec 2022 01:19:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234260AbiL3BS5 (ORCPT ); Thu, 29 Dec 2022 20:18:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229667AbiL3BSy (ORCPT ); Thu, 29 Dec 2022 20:18:54 -0500 Received: from mxct.zte.com.cn (mxct.zte.com.cn [183.62.165.209]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FB6B1C4 for ; Thu, 29 Dec 2022 17:18:53 -0800 (PST) Received: from mse-fl2.zte.com.cn (unknown [10.5.228.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mxct.zte.com.cn (FangMail) with ESMTPS id 4NjnTS10zfz501Qj; Fri, 30 Dec 2022 09:18:52 +0800 (CST) Received: from szxlzmapp05.zte.com.cn ([10.5.230.85]) by mse-fl2.zte.com.cn with SMTP id 2BU1IkTi061010; Fri, 30 Dec 2022 09:18:46 +0800 (+08) (envelope-from yang.yang29@zte.com.cn) Received: from mapi (szxlzmapp01[null]) by mapi (Zmail) with MAPI id mid14; Fri, 30 Dec 2022 09:18:47 +0800 (CST) Date: Fri, 30 Dec 2022 09:18:47 +0800 (CST) X-Zmail-TransId: 2b0363ae3c77ffffffffe91c6f06 X-Mailer: Zmail v1.0 Message-ID: <202212300918477352037@zte.com.cn> Mime-Version: 1.0 From: To: Cc: , , , , , , , , Subject: =?UTF-8?B?W1BBVENIIHY1IDYvNl0gc2VsZnRlc3Q6IGFkZCB0ZXN0aW5nIHVuc2hhcmluZyBhbmQgY291bnRpbmcga3NtIHplcm8KIHBhZ2U=?= Content-Type: text/plain; charset="UTF-8" X-MAIL: mse-fl2.zte.com.cn 2BU1IkTi061010 X-Fangmail-Gw-Spam-Type: 0 X-FangMail-Miltered: at cgslv5.04-192.168.251.13.novalocal with ID 63AE3C7C.000 by FangMail milter! 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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