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 E3BDF3D891F; Fri, 25 Sep 2026 12:55:01 +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=1790340904; cv=none; b=tGs+QTXrYmwf0MM7EDD0+ssFPNPmUkDF0XrPgsig7stB+3gwr9U92EZOnKIOIQGv2fR1uWaAyPrQnhdlRn7ZveEAMqghdbP+RmhfRbsfA1nP53eRVqA3bY1Fs9cbNdBJ+320/b5Apc3+OVVBp5Qt8eeRc+Hox/CbjmzJQi+etwQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790340904; c=relaxed/simple; bh=j/85jN3gYWWQWBvqu4uwZCoLwy7OMcYx99dC/0gNZ/0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Aqzt2iMErlBzBYUgVBuI/woF2zX9j3lWtoaUdMQCXJIBvlxocrsc1orRKmusm8bZZRnl2rGE4cXp2d9wRPI5AQ7GaDYZK2xAdRB/VtRLClGhEAj/OoF3dFm7L4IA1eqEom4qa3t6uZZC92zH6Ws+mBnH+k6UQs041n1HcotaO8g= 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=T2sDY/OT; 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="T2sDY/OT" 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 B6F40169C; Fri, 25 Sep 2026 05:54:57 -0700 (PDT) Received: from [10.164.19.84] (a081061.arm.com [10.164.19.84]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AA2733F86C; Fri, 25 Sep 2026 05:54:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790340901; bh=j/85jN3gYWWQWBvqu4uwZCoLwy7OMcYx99dC/0gNZ/0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=T2sDY/OT1wts5m+zf3YiB+h35c0wkFSU5O7wCdUM4ZIQDvj82832pGAwRVWgO6O4P ls3SAOPMKxbCbE73jt4apBpB5wtgH643FtHhgqzeN2vytVostVCok9iKdS/zDUhGem 4aG0r2e4ya4jwiIvb3KUc+KaEx2ck1IE42sZpUG8= Message-ID: <1dc9a608-16f0-445c-8e5d-a865d4ed0736@arm.com> Date: Fri, 25 Sep 2026 18:24:52 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 3/4] kselftest: mm: integrate huge page checks To: Yeoreum Yun , Andrew Morton , David Hildenbrand , 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 Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260924-fix_split-v8-0-cba7359d882a@arm.com> <20260924-fix_split-v8-3-cba7359d882a@arm.com> Content-Language: en-US From: Sarthak Sharma In-Reply-To: <20260924-fix_split-v8-3-cba7359d882a@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/25/26 12:41 AM, 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 > --- Looks good to me, some nits below. Reviewed-by: Sarthak Sharma [...] > -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_msg("open pagemap fail\n"); > > - for (; start < end; start += hpage_size) { > + kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY); > + if (kpageflags_fd < 0) > + ksft_exit_fail_msg("open kpageflags fail\n"); Again, can we change it to ksft_exit_fail_perror()? > + > + if (!check_pmd_mapping && > + !check_large_folios(pagemap_fd, kpageflags_fd, > + addr, len, nr_hpages, hpage_size)) > + goto out; > + > + for (; start < end; start += scan_mapping_size) { > categories = pagemap_scan_get_categories(pagemap_fd, start); > - if (!(categories & PAGE_IS_HUGE)) > - continue; > - if (check_huge_type(categories, type)) > + pfn = pagemap_get_pfn(pagemap_fd, start); > + if (pfn == -1UL) { > + if (!allow_nonpresent) > + goto out; > + else Nit: We can skip this else here. > + continue; > + } > + if (check_pmd_mapping && (categories & PAGE_IS_HUGE)) > nr_pmd_mappings++; > + if (!check_huge_type(categories, type)) > + goto out; > } > - close(pagemap_fd); > > - return nr_hpages == nr_pmd_mappings; > + if (check_pmd_mapping && (nr_pmd_mappings != nr_hpages)) > + goto out; > + ret = true; > + > +out: > + close(pagemap_fd); > + close(kpageflags_fd); > + return ret; > }