From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 92E2F3D0BEC; Tue, 29 Sep 2026 10:01:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790676108; cv=none; b=kcEnwtarhhBW6ikx85DICcVqXctO4SvgtzISmZgvHjwplF7+PnvoMzNu4yVe94Dy4GDOnD5KYkoSdV2/BWxCmiedVwYi7WzJl/nOccMnSikU/YVE9RHtLNmkMQCs2h5msIi4QMV5hZzbBqtvp9vYQS5iBX/stiWV6xWF98wC4mU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790676108; c=relaxed/simple; bh=sOf1yxpICIHQ0diMdP7xrm0ukUMRWepHeq2vSRPG4qQ=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=i3oD8h8v4MP2khiE2xCgu32CiJewK+SRpV54COo4VD6ttacaDEbDSyo/lBPJ/uweME4qp77WsIhK9je93jAY1JUE01JyWp50nLvQlz4/0jRZQbhyjTgaFGNnqYqoLySbOeJRNBWkuM3PZoHlOHZWR6il5DH2435PhHEFsqOjTJc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=JjsM4U0d; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="JjsM4U0d" 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 134DD1516; Tue, 29 Sep 2026 03:01:41 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 57C053F85F; Tue, 29 Sep 2026 03:01:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790676104; bh=sOf1yxpICIHQ0diMdP7xrm0ukUMRWepHeq2vSRPG4qQ=; h=Date:From:To:Subject:References:In-Reply-To:From; b=JjsM4U0dCWQiwBxbACDJ3APXp7SAAY6WZjEcCJGR+fkF0lJD+DKExuMsMdh+XnBDu i0z/7aw1bFIIV5rVltVcodA/qy/Z73WE/sqRztwIokaAaVcrTjcm6DLx8c/CDtsnYi fzYfg2Y59P6spKNrcItxhEh8ew13b7ZcHr9keCoA= Date: Tue, 29 Sep 2026 11:01:38 +0100 From: Yeoreum Yun To: "David Hildenbrand (Arm)" , Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Kevin Brodsky , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 3/4] kselftest: mm: integrate huge page checks Message-ID: References: <20260924-fix_split-v8-0-cba7359d882a@arm.com> <20260924-fix_split-v8-3-cba7359d882a@arm.com> <16f16e77-05ab-418e-ad06-8f48fb29375a@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16f16e77-05ab-418e-ad06-8f48fb29375a@kernel.org> On Tue, Sep 29, 2026 at 10:07:37AM +0200, David Hildenbrand (Arm) wrote: > On 9/24/26 21:11, Yeoreum Yun wrote: > > check_large_folios() only checks for large folios without distinguishing > > between anonymous and file-backed huge pages. > > > > To add huge page type checking, integrate the huge page checks into > > __check_huge(): > > > > 1. If hpage_size == pmd_pagesize, check PAGE_IS_HUGE instead of using > > check_large_folios(), since only the mapping type matters. This > > identifies PMD-mapped huge pages. > > > > 2. Otherwise, use check_large_folios() to detect large folios. This > > covers mTHP cases. > > > > 3. Check the folio flags according to the huge page type. > > > > Suggested-by: David Hildenbrand (Arm) > > Suggested-by: Zi Yan > > Signed-off-by: Yeoreum Yun > > --- > > Instead of merging both things (detecting mapping vs. detecting anon vs. file), > could we simply perform the anon vs. file change separately? > > Doing another pagemap walk that focuses on that should end up with something > that is easier to read. Okay. I'll change like below in next-spin: -------&<------- @@ -411,57 +400,78 @@ static bool check_huge_type(uint64_t categories, enum check_huge_type type) return false; } -static bool __check_pmd_huge(void *addr, size_t len, int nr_hpages, - uint64_t hpage_size, enum check_huge_type type) +static bool __check_huge(void *addr, size_t len, int nr_hpages, + uint64_t hpage_size, enum check_huge_type type) { { - int pagemap_fd; + bool ret = false; + int pagemap_fd, kpageflags_fd; int nr_pmd_mappings = 0; + uint64_t pmd_pagesize, scan_mapping_size; uint64_t categories; + unsigned long pfn; + bool check_pmd_mapping, allow_nonpresent; char *start = addr; char *end = start + len; + pmd_pagesize = read_pmd_pagesize(); + if (!pmd_pagesize) + ksft_exit_fail_msg("reading PMD pagesize failed\n"); + + check_pmd_mapping = hpage_size == pmd_pagesize; + scan_mapping_size = (nr_hpages > 0) ? hpage_size : psize(); + /* Some mTHP tests check a partially populated PMD-sized range. */ + allow_nonpresent = (uint64_t)nr_hpages * hpage_size < len; + pagemap_fd = open(PAGEMAP_PATH, O_RDONLY); if (pagemap_fd < 0) ksft_exit_fail_perror("open pagemap"); - for (; start < end; start += hpage_size) { + kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY); + if (kpageflags_fd < 0) + ksft_exit_fail_perror("open kpageflags"); + + for (; start < end; start += scan_mapping_size) { categories = pagemap_scan_get_categories(pagemap_fd, start); - if (!(categories & PAGE_IS_HUGE)) + pfn = pagemap_get_pfn(pagemap_fd, start); + if (pfn == -1UL) { + if (!allow_nonpresent) + goto out; continue; - if (check_huge_type(categories, type)) + } + if (!check_huge_type(categories, type)) + goto out; + } + + if (!check_pmd_mapping) { + ret = check_large_folios(pagemap_fd, kpageflags_fd, + addr, len, nr_hpages, hpage_size); + goto out; + } + + for (start = addr; start < end; start += scan_mapping_size) { + categories = pagemap_scan_get_categories(pagemap_fd, start); + if (categories & PAGE_IS_HUGE) nr_pmd_mappings++; } - close(pagemap_fd); - return nr_hpages == nr_pmd_mappings; + if (nr_pmd_mappings != nr_hpages) + goto out; + ret = true; + +out: + close(pagemap_fd); + close(kpageflags_fd); + return ret; } -- Sincerely, Yeoreum Yun