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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D31CEC32793 for ; Wed, 18 Jan 2023 14:26:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5BB506B0071; Wed, 18 Jan 2023 09:26:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 544636B0072; Wed, 18 Jan 2023 09:26:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3BD516B0074; Wed, 18 Jan 2023 09:26:23 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 260B76B0071 for ; Wed, 18 Jan 2023 09:26:23 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id E22EE120BFB for ; Wed, 18 Jan 2023 14:26:22 +0000 (UTC) X-FDA: 80368145004.24.4223999 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf08.hostedemail.com (Postfix) with ESMTP id DED13160023 for ; Wed, 18 Jan 2023 14:26:15 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=flKbb9+z; spf=pass (imf08.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1674051980; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=g06cdjA6Y1YmHGhcKb7SPdcn8qSEd7bjUCxNp9yfSiQ=; b=zOQ8wRzuFBYEykKesiz9lH+Jbf/xwgaAP5q4XqTtyYfobidHK+0OzQRCHVHf/lPcMMK0BW VjvuQ1unNYkkF4MxjsG5FjWunr5VFGE0mvuYOJ/Nu4r6NOttKZXDtQPDww+eLtcbGr3Bb1 4jGqhMciWR4yqYxLCly7wAyR2PKiZlQ= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=flKbb9+z; spf=pass (imf08.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1674051980; a=rsa-sha256; cv=none; b=TUNrgE5+DhSaEVBb14P3Ngpf2PpQD8ksiFB+5fw5y50Xq/N6hKcYdhYtMZtq5cb8R2HpjD 5VRd4n7Dj5cDz1jVql9dTJNVEjEwp3SIgAyhCHblQ2j1BJEQvWAekFcEcWkE7j5h3gPKG2 lCdTR+lW1k5086Vo55/iBGizRT9Uexc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674051975; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=g06cdjA6Y1YmHGhcKb7SPdcn8qSEd7bjUCxNp9yfSiQ=; b=flKbb9+z784peNsVPIfH88MTd8JDtviu2ddrDdNmLOr5dn6umZ8avmzu9aKN28nF/cL/oB quUh9h2lo78fWbDOTLHkphVtuTixD5pAyJ3j2kLHYiYD+928sJ9pH1UfdsD0GmM8jYJ4wc 3w7Way/WE7ocSThnCYG5JTYOLCqJQrg= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-623-kKLG1Xu8NPmJzgb_7aw-Lw-1; Wed, 18 Jan 2023 09:26:11 -0500 X-MC-Unique: kKLG1Xu8NPmJzgb_7aw-Lw-1 Received: by mail-wm1-f71.google.com with SMTP id g9-20020a7bc4c9000000b003d214cffa4eso563713wmk.5 for ; Wed, 18 Jan 2023 06:26:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:subject:organization:from :references:cc:to:content-language:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=g06cdjA6Y1YmHGhcKb7SPdcn8qSEd7bjUCxNp9yfSiQ=; b=PfozfdSOrRTDcwEz+lZ4WpQPsTDF+hxL+ukvOIQW6MyDYxE9lXASkAd2lB3vqiO7ux tL/+aED+4PHh0p5y88xhQcfi1OuiEZfmAoM8UfgcTwgSevaO1OzZJ080CoPe0vsckAx2 6OD9zJkvaOkrv8g9oLh+XJ8wEloZGc6s+jSbjxVpOpYpAc9uzdsHawHtjhjt7eHgeAny bcyUY72Q/rjCPtDKYkjaV5fHIPwFTRlrEUn/TaUd+ufuQH2s6DB2P/RV71OAxwbDZ+qH IRXrWHK2Jh8frcLWOTSfbY0qi55KMjdyPI45By9rzK4klXg8nGb0Z1JwDhKmlyKLRu1U uotA== X-Gm-Message-State: AFqh2koO2LMbCJcnTZFeRbih9U5VusYDB+yH7I/V0ELxo0+Gn3Fba5+t mWeXit9fk5Cqi5hm4PeqP6Phz4FfCy/zXjb5P3bxQ3x24J5kvo3C5C0rjDFJC/166SeJJHnzQ51 3G5GVR9oaSfI= X-Received: by 2002:a1c:f617:0:b0:3d2:191d:2420 with SMTP id w23-20020a1cf617000000b003d2191d2420mr6765365wmc.7.1674051970242; Wed, 18 Jan 2023 06:26:10 -0800 (PST) X-Google-Smtp-Source: AMrXdXs8qt2aUQTMf4NiwYQSMfy0TkaQhHKLrhb7WoCi5t6BJc9U5DppBmazAWsNoJuY1A5pOdpI3A== X-Received: by 2002:a1c:f617:0:b0:3d2:191d:2420 with SMTP id w23-20020a1cf617000000b003d2191d2420mr6765343wmc.7.1674051969945; Wed, 18 Jan 2023 06:26:09 -0800 (PST) Received: from ?IPV6:2003:cb:c705:800:1a88:f98a:d223:c454? (p200300cbc70508001a88f98ad223c454.dip0.t-ipconnect.de. [2003:cb:c705:800:1a88:f98a:d223:c454]) by smtp.gmail.com with ESMTPSA id p4-20020a05600c1d8400b003da286f8332sm2273274wms.18.2023.01.18.06.26.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Jan 2023 06:26:09 -0800 (PST) Message-ID: <3704dcf0-bd0a-8ab2-7f4f-045fc7c73171@redhat.com> Date: Wed, 18 Jan 2023 15:26:08 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 To: yang.yang29@zte.com.cn, akpm@linux-foundation.org Cc: imbrenda@linux.ibm.com, jiang.xuexin@zte.com.cn, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ran.xiaokai@zte.com.cn, xu.xin.sc@gmail.com, xu.xin16@zte.com.cn References: <202212300918477352037@zte.com.cn> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH v5 6/6] selftest: add testing unsharing and counting ksm zero page In-Reply-To: <202212300918477352037@zte.com.cn> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: DED13160023 X-Stat-Signature: bcnchwzbyhjkdz5ezqqfoykxwpa5wbsw X-Rspam-User: X-HE-Tag: 1674051975-469871 X-HE-Meta: U2FsdGVkX1+AFM4ELtStyBJaKLUbHzFQ5sCtFcEEvKEhRrPWo4Q5Tcy5UcN4zIcsi4SRK8IdkIGYnPp7c6fsiw2qBZh3UCsEF/ur6nnZyn3scSx9mkenqwCSplTTqbqrsXFkqQJXc1Rjjm27aLQurZz7oR/YpVDDDU3UFJw+XA/LSyN45yeXMhRtkiY4Yij5EL1oMRgw6T3hCjiTcvygydEr4MlaI4v7zy7FMK8Ein6R/avSqu/aXQyNziMc/cowfM1jnnH6nGBZwdJ443+3XFo3wrb1RMV+Wifr+k1nU4ce3672iIG3u0Ktq6tnBN8sHT7N2FooBgT47xNIKGaDZx5QNWsW3I3t2U/YBnXqzMUercozlmfyllogf9+BFAJpA/Lvg+r2ACHSiZZZsy+reZN3fZ1BRowzfHIhs6dFyPI2roJgbs/ke8dgixlP8iENpqt7uGw9cMYFU6C1O7SoipcXliDhVZsDBDQBWtymw49nuUzJUtKrlhUmJhAvCMJz81iBEavuk7N7edOEouKAI/pGje8TrhAcd3mUQJSIe4TtwEofjkaNl4asMWNIQoiPh2HIXYBeSZ4lwZrPpM8UUm0pS2xvUVXBcJp2sukpWGNJB6/4VYnxTyNKgx+9ews0Buh/tthQiksfAGEyo4+qa8YW+q6lo+lDGct/uohMaCvTnwbLyLYVUR/BUOd1H8FQjFWdf5JKCY+JGu51CzQeULhoFOJKHzrDJDSokMDqvZexk6qZTrm0Il+HLWtbLC0EMKFum5YbGV7dXw0jgznNjNS5YsMyODIQhEXYP/4pdjsj4DuBIoxb8sZFT6SGRWqboG0dgNg+e7G3QnAtn4Iz/R36kDGuWXIC7L71sFShMdSVs3zD04toDfePfucnxaVwXCD6aYNchQyfexZclCi2ZJ4qWGBw5lMdWDGY+sckKEX63P6Jw4f6zM7H0i37ZmPy7QfE/XSa6YYbD/FuAB2 XuA23STe swBST59aJsfxGGlNR5S/fDEWGLyDkJMWTJjoBHfh9mAVc+do035ikeTckrG7swAOGmG7hG582f5G1GrghS4KGEyLXqCn3YqhcEB/5zpcyeSBHRP/3g7qn53COjP0qyOQ5EZlZOBx4PZfRuJ1/n6ECrA8KcChKwk8oAnnCzEpzWF9q9cYTefgx+Z3ptjuiZcGzP37PpepUzoOkogY9ItgOBOD/vQ== 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: On 30.12.22 02:18, yang.yang29@zte.com.cn wrote: > 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; If they are global, open them from main(), not from the test case. > 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; Better call this function "ksm_get_zero_pages", do it similarly to ksm_get_full_scans() and do the comparison in the kernel. > +} > + > 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; This change might not be required. > 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(); Why is that required? > +} > + > +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(); Dito, why is that required when unmerging? > +} > + > 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); Not checking for map == MAP_FAILED. Best to follow what test_unmerge() does. > + > + /* 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"); > + Let's keep COW tests to cow.c and focus on explicit unmerging here. Once we add support for KSM in cow.c , we can also test that e.g., long-term R/O pinning works as expected. I have that on my todo list but would be pleasantly surprised if someone else could tackle it :) > + /* 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; > + } Just avoid that helper and do it like test_unmerge(). Keep it simple. > + ksft_test_result(check_ksm_zero_pages_count(size / 4), > + "zero page count react to unmerge\n"); > + > + /*Check if ksm pages are really unmerged */ Missing space at the beginning. + the comment is superfluous. > + 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"); > + Unrelated change. > 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(); -- Thanks, David / dhildenb