From nobody Wed Dec 17 17:22:14 2025 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 A0921C77B78 for ; Tue, 18 Apr 2023 15:30:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231599AbjDRPal (ORCPT ); Tue, 18 Apr 2023 11:30:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231701AbjDRPaf (ORCPT ); Tue, 18 Apr 2023 11:30:35 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 152A01FCA for ; Tue, 18 Apr 2023 08:29:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681831744; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=O7hwLzEYfyCC+1HV0+CQuKr6XrxBkPdmXIv3+pwAsAU=; b=bmfoqXYvEjJIxh9L2VOAgzyxW6hxU1TVQEii7fKesGNn04IKohG0D51mitHh4XoyMpvVNG dMloIUPNiWlTzyb14lzh6OjvhpEUE8rU8n71TdfgDBBUJnwhBKh3DHUChk1ii7zUu9aCZT 4RiNPu6hRGq9t3fzWT+/LpOAcH23SAw= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-283-tx5a0GuAONunj9TrLi1nxQ-1; Tue, 18 Apr 2023 11:29:01 -0400 X-MC-Unique: tx5a0GuAONunj9TrLi1nxQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 048921C0A58F; Tue, 18 Apr 2023 15:29:00 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id B148314152F6; Tue, 18 Apr 2023 15:28:57 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org, David Hildenbrand , Andrew Morton , Stefan Roesch , Rik van Riel , Johannes Weiner , Michal Hocko , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Shuah Khan Subject: [PATCH v1 2/3] selftests/ksm: ksm_functional_tests: add prctl unmerge test Date: Tue, 18 Apr 2023 17:28:48 +0200 Message-Id: <20230418152849.505124-3-david@redhat.com> In-Reply-To: <20230418152849.505124-1-david@redhat.com> References: <20230418051342.1919757-1-shr@devkernel.io> <20230418152849.505124-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Let's test whether setting PR_SET_MEMORY_MERGE to 0 after setting it to 1 will unmerge pages, similar to how setting MADV_UNMERGEABLE after setting MADV_MERGEABLE would. Signed-off-by: David Hildenbrand Acked-by: Stefan Roesch --- .../selftests/mm/ksm_functional_tests.c | 46 ++++++++++++++++--- 1 file changed, 40 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/test= ing/selftests/mm/ksm_functional_tests.c index 7bc9fc17c9f0..26853badae70 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -91,9 +91,10 @@ static int ksm_merge(void) return 0; } =20 -static char *mmap_and_merge_range(char val, unsigned long size) +static char *mmap_and_merge_range(char val, unsigned long size, bool use_p= rctl) { char *map; + int ret; =20 map =3D mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0); @@ -110,7 +111,17 @@ static char *mmap_and_merge_range(char val, unsigned l= ong size) =20 /* Make sure each page contains the same values to merge them. */ memset(map, val, size); - if (madvise(map, size, MADV_MERGEABLE)) { + + if (use_prctl) { + ret =3D prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); + if (ret < 0 && errno =3D=3D EINVAL) { + ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); + goto unmap; + } else if (ret) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=3D1 failed\n"); + goto unmap; + } + } else if (madvise(map, size, MADV_MERGEABLE)) { ksft_test_result_fail("MADV_MERGEABLE failed\n"); goto unmap; } @@ -133,7 +144,7 @@ static void test_unmerge(void) =20 ksft_print_msg("[RUN] %s\n", __func__); =20 - map =3D mmap_and_merge_range(0xcf, size); + map =3D mmap_and_merge_range(0xcf, size, false); if (map =3D=3D MAP_FAILED) return; =20 @@ -155,7 +166,7 @@ static void test_unmerge_discarded(void) =20 ksft_print_msg("[RUN] %s\n", __func__); =20 - map =3D mmap_and_merge_range(0xcf, size); + map =3D mmap_and_merge_range(0xcf, size, false); if (map =3D=3D MAP_FAILED) return; =20 @@ -187,7 +198,7 @@ static void test_unmerge_uffd_wp(void) =20 ksft_print_msg("[RUN] %s\n", __func__); =20 - map =3D mmap_and_merge_range(0xcf, size); + map =3D mmap_and_merge_range(0xcf, size, false); if (map =3D=3D MAP_FAILED) return; =20 @@ -323,9 +334,31 @@ static void test_prctl_fork(void) ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n"); } =20 +static void test_prctl_unmerge(void) +{ + const unsigned int size =3D 2 * MiB; + char *map; + + ksft_print_msg("[RUN] %s\n", __func__); + + map =3D mmap_and_merge_range(0xcf, size, true); + if (map =3D=3D MAP_FAILED) + return; + + if (prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0)) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=3D0 failed\n"); + goto unmap; + } + + ksft_test_result(!range_maps_duplicates(map, size), + "Pages were unmerged\n"); +unmap: + munmap(map, size); +} + int main(int argc, char **argv) { - unsigned int tests =3D 4; + unsigned int tests =3D 5; int err; =20 #ifdef __NR_userfaultfd @@ -355,6 +388,7 @@ int main(int argc, char **argv) =20 test_prctl(); test_prctl_fork(); + test_prctl_unmerge(); =20 err =3D ksft_get_fail_cnt(); if (err) --=20 2.39.2