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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A542B1090240 for ; Thu, 19 Mar 2026 15:42:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A7B226B0510; Thu, 19 Mar 2026 11:42:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9B5C56B0512; Thu, 19 Mar 2026 11:42:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7BA356B0513; Thu, 19 Mar 2026 11:42:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 5BD996B0510 for ; Thu, 19 Mar 2026 11:42:16 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id A718713B19D for ; Thu, 19 Mar 2026 15:42:15 +0000 (UTC) X-FDA: 84563229030.14.B965C1B Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf12.hostedemail.com (Postfix) with ESMTP id F3E1340017 for ; Thu, 19 Mar 2026 15:42:13 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Z018L9Ma; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf12.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1773934934; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=lc95fE5PcKpVoqjQZVE/Y3nTvuJLsNcMVpnAyeEHQM8=; b=jVF5zr9ZV9tCYe4D4htC4WFHaqxiWJ1Xn0kWLxwkORO7C5jeLGJdmO1kLJpgQdemWeqi4h vN+DY1880ZZqVLx4JFOB7oD+pv5UnpRbgv9AhYcYgim9h3WI0JflY801CgtSlSePcn7ADU b++0qwgFHoGI5HZRTlZtv+A8MTiszeo= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1773934934; a=rsa-sha256; cv=none; b=z2HOdCwEypKlp0rHAlgtk6+kMtqjjejvUFRgEI8TqUrV79pR9dAExl/Wk1Put0KsI2XVpX r7U0DuLttWJ/Yt/Y47bepZHoKj2SLc2hRJPchKo7nsF6g4p7usEgeqygsJGpkuhu3e9Qzb CirgFFRO2M3H9Ar0qi/MbevsIAeAP8I= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Z018L9Ma; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf12.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 5A5B060097; Thu, 19 Mar 2026 15:42:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75EEAC19424; Thu, 19 Mar 2026 15:42:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773934933; bh=ddwCQSambwYhQk+Gsdfv4G9cQ4n4k0xN/Xf5jL5ONSU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z018L9Mak6kJMccjvcDtf9kU/gKi2xvWqu3Nn24TK/JUCbiVBonRRqd9vGgzuKqc6 a7MZUk1D5gPNrtaqHxzmo7toXNDIsCnJgjlbap47KUZP52UrYfIlOcdn1mX340p3MS o7kPN5nendZl6j4TQJQD0QAC337GqDQJrMnyOXi5tKmBB/xH4TFMhEgSXdrhYQ8d0A VpTfsK862COAupBKT5D+iLtiIf1kZNqUKaKRXOycyq+RjGiZFSjTs7aapyfZM9C+df NNhyAxNRNuOh4sarGLaHaNAET257IrdhIg1tGmDQjKglosykUDoKj4wfDyyrUAbsZl wXPDOxkUEGj+w== Date: Thu, 19 Mar 2026 17:42:06 +0200 From: Mike Rapoport To: Chris Down Cc: Andrew Morton , Peter Xu , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Matthew Wilcox , kernel-team@fb.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] selftests/mm: Add UFFDIO_MOVE huge zeropage PMD regression test Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: F3E1340017 X-Stat-Signature: 6mgymtrdfjk5k6qnqdkagnfouksyybgo X-Rspam-User: X-HE-Tag: 1773934933-429097 X-HE-Meta: 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 aPAXxaZM Px15CTC9ZPdRYq7BXBY0pGmeLpvCMNI/gk7l38vWwhiV6JmxL5+J6RE10pd+rQ2uSyAaw9P63ELfkn7STjz/7exezgIuYwQpvoE5aTn+qT7a3e6dqwMJpbiLOpe+00Om1evCq8RNJ28MA2+MHsbt/2ea4p5Iy8g/jhD8oiugUbh4Xxt8XyhZbHAnayhvucdKZ6GEmvWFdsrfm1rab/HjUcEEI2ps9X/sdlUSjr5arZ8U/4ScE24zYRM4a6EuLj9swF9hNb+FifbWvTl4EPj7PuhAn8HQ6pVgyWUsOIxFN7LSmIp3j7Oin3dydUhiNViFM/L2b2/ZOgVmhQlE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Mar 18, 2026 at 12:18:11PM +0800, Chris Down wrote: > The existing uffd-unit-tests move-pmd coverage exercises PMD-sized > UFFDIO_MOVE on anonymous THPs, but it does not force the huge zeropage > PMD path in move_pages_huge_pmd(). > > Add a dedicated anonymous UFFDIO_MOVE PMD test that exercises this > relatively comprehensively. > > Signed-off-by: Chris Down Reviewed-by: Mike Rapoport (Microsoft) > --- > tools/testing/selftests/mm/uffd-unit-tests.c | 100 +++++++++++++++++++ > tools/testing/selftests/mm/vm_util.c | 12 +++ > tools/testing/selftests/mm/vm_util.h | 1 + > 3 files changed, 113 insertions(+) > > diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c > index 6f5e404a446c..9cc4cbab9a23 100644 > --- a/tools/testing/selftests/mm/uffd-unit-tests.c > +++ b/tools/testing/selftests/mm/uffd-unit-tests.c > @@ -1227,6 +1227,99 @@ static void uffd_move_pmd_test(uffd_global_test_opts_t *gopts, uffd_test_args_t > uffd_move_pmd_handle_fault); > } > > +static void uffd_move_pmd_huge_zeropage_test(uffd_global_test_opts_t *gopts, > + uffd_test_args_t *targs) > +{ > + unsigned long pmd_size = read_pmd_pagesize(); > + unsigned long pmd_pages; > + unsigned long bytes = gopts->nr_pages * gopts->page_size; > + char *orig_area_src = gopts->area_src, *orig_area_dst = gopts->area_dst; > + char *aligned_src, *aligned_dst; > + unsigned long src_offs, dst_offs, max_offs; > + pthread_t uffd_mon; > + struct uffd_args args = { 0 }; > + char c = '\0'; > + int pagemap_fd; > + > + if (pmd_size <= gopts->page_size) { > + uffd_test_skip("huge page size is 0, feature missing?"); > + return; > + } > + if (!detect_huge_zeropage()) { > + uffd_test_skip("transparent huge zeropage disabled"); > + return; > + } > + > + pmd_pages = pmd_size / gopts->page_size; > + if (bytes < pmd_size) { > + uffd_test_skip("not enough pages for one PMD-sized move"); > + return; > + } > + > + aligned_src = ALIGN_UP(orig_area_src, pmd_size); > + aligned_dst = ALIGN_UP(orig_area_dst, pmd_size); > + src_offs = (aligned_src - orig_area_src) / gopts->page_size; > + dst_offs = (aligned_dst - orig_area_dst) / gopts->page_size; > + max_offs = src_offs > dst_offs ? src_offs : dst_offs; > + if (max_offs + pmd_pages > gopts->nr_pages) { > + uffd_test_skip("could not find aligned PMD-sized src/dst window"); > + return; > + } > + > + if (madvise(orig_area_dst, bytes, MADV_HUGEPAGE)) > + err("madvise(MADV_HUGEPAGE) failure"); > + if (madvise(orig_area_src, bytes, MADV_DONTFORK)) > + err("madvise(MADV_DONTFORK) failure"); > + if (madvise(aligned_src, pmd_size, MADV_DONTNEED)) > + err("madvise(MADV_DONTNEED) failure"); > + > + /* Fault in a PMD-sized huge zeropage mapping in the source. */ > + force_read_pages(aligned_src, pmd_pages, gopts->page_size); > + > + pagemap_fd = pagemap_open(); > + if (!pagemap_is_huge_zero(pagemap_fd, aligned_src)) { > + close(pagemap_fd); > + uffd_test_skip("could not fault in the huge zeropage"); > + return; > + } > + gopts->area_src = aligned_src; > + gopts->area_dst = aligned_dst; > + > + if (uffd_register(gopts->uffd, gopts->area_dst, pmd_size, true, false, false)) > + err("register failure"); > + > + args.gopts = gopts; > + args.handle_fault = uffd_move_pmd_handle_fault; > + if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) > + err("uffd_poll_thread create"); > + > + /* > + * One fault on dst should trigger a single PMD-sized UFFDIO_MOVE from > + * the huge zeropage PMD we populated in the source. > + */ > + force_read_pages(gopts->area_dst, pmd_pages, gopts->page_size); > + > + if (write(gopts->pipefd[1], &c, sizeof(c)) != sizeof(c)) > + err("pipe write"); > + if (pthread_join(uffd_mon, NULL)) > + err("join() failed"); > + > + if (args.missing_faults != 1 || args.minor_faults != 0) { > + uffd_test_fail("stats check error"); > + } else if (!pagemap_is_huge_zero(pagemap_fd, gopts->area_dst)) { > + uffd_test_fail("moved destination is not a huge zeropage PMD"); > + } else if (!check_huge_anon(gopts->area_dst, 0, pmd_size)) { > + /* vm_normal_page_pmd() must continue to treat the moved PMD as special. */ > + uffd_test_fail("moved huge zeropage PMD counted as AnonHugePages"); > + } else { > + uffd_test_pass(); > + } > + > + gopts->area_src = orig_area_src; > + gopts->area_dst = orig_area_dst; > + close(pagemap_fd); > +} > + > static void uffd_move_pmd_split_test(uffd_global_test_opts_t *gopts, uffd_test_args_t *targs) > { > if (madvise(gopts->area_dst, gopts->nr_pages * gopts->page_size, MADV_NOHUGEPAGE)) > @@ -1550,6 +1643,13 @@ uffd_test_case_t uffd_tests[] = { > .uffd_feature_required = UFFD_FEATURE_MOVE, > .test_case_ops = &uffd_move_test_pmd_case_ops, > }, > + { > + .name = "move-pmd-huge-zeropage", > + .uffd_fn = uffd_move_pmd_huge_zeropage_test, > + .mem_targets = MEM_ANON, > + .uffd_feature_required = UFFD_FEATURE_MOVE, > + .test_case_ops = &uffd_move_test_pmd_case_ops, > + }, > { > .name = "move-pmd-split", > .uffd_fn = uffd_move_pmd_split_test, > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c > index a6d4ff7dfdc0..55cc4cc058a2 100644 > --- a/tools/testing/selftests/mm/vm_util.c > +++ b/tools/testing/selftests/mm/vm_util.c > @@ -120,6 +120,18 @@ bool pagemap_is_populated(int fd, char *start) > PAGE_IS_PRESENT | PAGE_IS_SWAPPED); > } > > +bool pagemap_is_huge_zero(int fd, char *start) > +{ > + uint64_t categories; > + > + if (!pagemap_scan_supported(fd, start)) > + return false; > + > + categories = pagemap_scan_get_categories(fd, start); > + return (categories & (PAGE_IS_PRESENT | PAGE_IS_PFNZERO | PAGE_IS_HUGE)) == > + (PAGE_IS_PRESENT | PAGE_IS_PFNZERO | PAGE_IS_HUGE); > +} > + > unsigned long pagemap_get_pfn(int fd, char *start) > { > uint64_t entry = pagemap_get_entry(fd, start); > diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h > index e9c4e24769c1..e0b6ae1b12f5 100644 > --- a/tools/testing/selftests/mm/vm_util.h > +++ b/tools/testing/selftests/mm/vm_util.h > @@ -85,6 +85,7 @@ uint64_t pagemap_get_entry(int fd, char *start); > bool pagemap_is_softdirty(int fd, char *start); > bool pagemap_is_swapped(int fd, char *start); > bool pagemap_is_populated(int fd, char *start); > +bool pagemap_is_huge_zero(int fd, char *start); > unsigned long pagemap_get_pfn(int fd, char *start); > void clear_softdirty(void); > bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len); > > base-commit: f0caa1d49cc07b30a7e2f104d3853ec6dc1c3cad > -- > 2.53.0 > -- Sincerely yours, Mike.