From nobody Fri Dec 19 09:30:38 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 53B9AC4167B for ; Thu, 7 Dec 2023 16:13:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235301AbjLGQN2 (ORCPT ); Thu, 7 Dec 2023 11:13:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232960AbjLGQNH (ORCPT ); Thu, 7 Dec 2023 11:13:07 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 178CE19A6 for ; Thu, 7 Dec 2023 08:12:52 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7819A15A1; Thu, 7 Dec 2023 08:13:38 -0800 (PST) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B0DD83F762; Thu, 7 Dec 2023 08:12:49 -0800 (PST) From: Ryan Roberts To: Andrew Morton , Matthew Wilcox , Yin Fengwei , David Hildenbrand , Yu Zhao , Catalin Marinas , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain , Itaru Kitayama , "Kirill A. Shutemov" , John Hubbard , David Rientjes , Vlastimil Babka , Hugh Dickins , Kefeng Wang , Barry Song <21cnbao@gmail.com>, Alistair Popple Cc: Ryan Roberts , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v9 08/10] selftests/mm/khugepaged: Enlighten for multi-size THP Date: Thu, 7 Dec 2023 16:12:09 +0000 Message-Id: <20231207161211.2374093-9-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231207161211.2374093-1-ryan.roberts@arm.com> References: <20231207161211.2374093-1-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The `collapse_max_ptes_none` test was previously failing when a THP size less than PMD-size had enabled=3D"always". The root cause is because the test faults in 1 page less than the threshold it set for collapsing. But when THP is enabled always, we "over allocate" and therefore the threshold is passed, and collapse unexpectedly succeeds. Solve this by enlightening khugepaged selftest. Add a command line option to pass in the desired THP size that should be used for all anonymous allocations. The harness will then explicitly configure a THP size as requested and modify the `collapse_max_ptes_none` test so that it faults in the threshold minus the number of pages in the configured THP size. If no command line option is provided, default to order 0, as per previous behaviour. I chose to use an order in the command line interface, since this makes the interface agnostic of base page size, making it easier to invoke from run_vmtests.sh. Tested-by: Kefeng Wang Tested-by: John Hubbard Signed-off-by: Ryan Roberts --- tools/testing/selftests/mm/khugepaged.c | 48 +++++++++++++++++------ tools/testing/selftests/mm/run_vmtests.sh | 2 + 2 files changed, 39 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selfte= sts/mm/khugepaged.c index 7bd3baa9d34b..829320a519e7 100644 --- a/tools/testing/selftests/mm/khugepaged.c +++ b/tools/testing/selftests/mm/khugepaged.c @@ -28,6 +28,7 @@ static unsigned long hpage_pmd_size; static unsigned long page_size; static int hpage_pmd_nr; +static int anon_order; =20 #define PID_SMAPS "/proc/self/smaps" #define TEST_FILE "collapse_test_file" @@ -607,6 +608,11 @@ static bool is_tmpfs(struct mem_ops *ops) return ops =3D=3D &__file_ops && finfo.type =3D=3D VMA_SHMEM; } =20 +static bool is_anon(struct mem_ops *ops) +{ + return ops =3D=3D &__anon_ops; +} + static void alloc_at_fault(void) { struct thp_settings settings =3D *thp_current_settings(); @@ -673,6 +679,7 @@ static void collapse_max_ptes_none(struct collapse_cont= ext *c, struct mem_ops *o int max_ptes_none =3D hpage_pmd_nr / 2; struct thp_settings settings =3D *thp_current_settings(); void *p; + int fault_nr_pages =3D is_anon(ops) ? 1 << anon_order : 1; =20 settings.khugepaged.max_ptes_none =3D max_ptes_none; thp_push_settings(&settings); @@ -686,10 +693,10 @@ static void collapse_max_ptes_none(struct collapse_co= ntext *c, struct mem_ops *o goto skip; } =20 - ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size); + ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none - fault_nr_pages) * page_s= ize); c->collapse("Maybe collapse with max_ptes_none exceeded", p, 1, ops, !c->enforce_pte_scan_limits); - validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size); + validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - fault_nr_pages) * p= age_size); =20 if (c->enforce_pte_scan_limits) { ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size); @@ -1076,7 +1083,7 @@ static void madvise_retracted_page_tables(struct coll= apse_context *c, =20 static void usage(void) { - fprintf(stderr, "\nUsage: ./khugepaged [dir]\n\n"); + fprintf(stderr, "\nUsage: ./khugepaged [OPTIONS] [dir]\n\n"); fprintf(stderr, "\t\t: :\n"); fprintf(stderr, "\t\t: [all|khugepaged|madvise]\n"); fprintf(stderr, "\t\t: [all|anon|file|shmem]\n"); @@ -1085,15 +1092,34 @@ static void usage(void) fprintf(stderr, "\tCONFIG_READ_ONLY_THP_FOR_FS=3Dy\n"); fprintf(stderr, "\n\tif [dir] is a (sub)directory of a tmpfs mount, tmpfs= must be\n"); fprintf(stderr, "\tmounted with huge=3Dmadvise option for khugepaged test= s to work\n"); + fprintf(stderr, "\n\tSupported Options:\n"); + fprintf(stderr, "\t\t-h: This help message.\n"); + fprintf(stderr, "\t\t-s: mTHP size, expressed as page order.\n"); + fprintf(stderr, "\t\t Defaults to 0. Use this size for anon allocation= s.\n"); exit(1); } =20 -static void parse_test_type(int argc, const char **argv) +static void parse_test_type(int argc, char **argv) { + int opt; char *buf; const char *token; =20 - if (argc =3D=3D 1) { + while ((opt =3D getopt(argc, argv, "s:h")) !=3D -1) { + switch (opt) { + case 's': + anon_order =3D atoi(optarg); + break; + case 'h': + default: + usage(); + } + } + + argv +=3D optind; + argc -=3D optind; + + if (argc =3D=3D 0) { /* Backwards compatibility */ khugepaged_context =3D &__khugepaged_context; madvise_context =3D &__madvise_context; @@ -1101,7 +1127,7 @@ static void parse_test_type(int argc, const char **ar= gv) return; } =20 - buf =3D strdup(argv[1]); + buf =3D strdup(argv[0]); token =3D strsep(&buf, ":"); =20 if (!strcmp(token, "all")) { @@ -1135,11 +1161,13 @@ static void parse_test_type(int argc, const char **= argv) if (!file_ops) return; =20 - if (argc !=3D 3) + if (argc !=3D 2) usage(); + + get_finfo(argv[1]); } =20 -int main(int argc, const char **argv) +int main(int argc, char **argv) { int hpage_pmd_order; struct thp_settings default_settings =3D { @@ -1164,9 +1192,6 @@ int main(int argc, const char **argv) =20 parse_test_type(argc, argv); =20 - if (file_ops) - get_finfo(argv[2]); - setbuf(stdout, NULL); =20 page_size =3D getpagesize(); @@ -1183,6 +1208,7 @@ int main(int argc, const char **argv) default_settings.khugepaged.max_ptes_shared =3D hpage_pmd_nr / 2; default_settings.khugepaged.pages_to_scan =3D hpage_pmd_nr * 8; default_settings.hugepages[hpage_pmd_order].enabled =3D THP_INHERIT; + default_settings.hugepages[anon_order].enabled =3D THP_ALWAYS; =20 save_settings(); thp_push_settings(&default_settings); diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/self= tests/mm/run_vmtests.sh index c0212258b852..87f513f5cf91 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -357,6 +357,8 @@ CATEGORY=3D"cow" run_test ./cow =20 CATEGORY=3D"thp" run_test ./khugepaged =20 +CATEGORY=3D"thp" run_test ./khugepaged -s 2 + CATEGORY=3D"thp" run_test ./transhuge-stress -d 20 =20 CATEGORY=3D"thp" run_test ./split_huge_page_test --=20 2.25.1