From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DDAC423D7FF; Thu, 1 Oct 2026 11:40:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790854817; cv=none; b=CvH18rLFuL+tHPqavFiTAd3MsRevdqtYUEAtL0QoQHokxGH94lnpyJWdW1ai/R+/HVQDsrJpCD7isijdHS92XkeV1Bx5a8OSorgBBPrYLDvZASlegFl6bRvXVUW6or0fEbmiQIExpcOXV5T/ulOjL5RnLEwOpbw/JMi+hbnkI4Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790854817; c=relaxed/simple; bh=lGps2LNFvq9etSUgZN4EzP27oJQU5/5U260/hM7QV2U=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=iFPT4Yfw27tbNKlRxrqY6Y5qZUzlVQR5HQ0ASBLVqQjXw3gH57ZBaZ71O4H8BCQ84ye1LP3/jv7ks4AIvHYgFx8CDE/VxVR2+q/oSIait1E9lychEZx8frkYgrN7voHZbqha7jHztDuSu2UWK3Uc+L1+9lK2e1BEKTj2RXk+gXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PUupB5gQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PUupB5gQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B055D1F000FF; Thu, 1 Oct 2026 11:40:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790854815; bh=R8QnVRuxXx0DRHjhLodBsB0dPH0Vc9e66VDO/VON7WE=; h=Date:Subject:To:References:From:In-Reply-To; b=PUupB5gQlzr+bWtFrTHfgVpwkTN7x++K9kI8wfHEPTjtHMkwKqyI5WDWii0Bkkdm8 zc+/P0XWsRcF7derKkF83f7dkkQc1UWQelBTuOtpZ/gyAomoRXsifxd4luvWVBD3ER TNQ2PESLWmY6by6SyG+A+EUs5kmjXWnECiwaagON8c8jwJG3jtik1eKSgLol4paxDr wYHUnf6dCWnKcvULC69CJnKHJRP34dqQqmv3TFIugxWuTWrJDeeDJJV4e6n9vxHzzD srwh8e1g+YjOwg3w4ItlCE5jLfQT8SVJ4wjtkI4PFRLphYU+I+lLPhvTLFJuGLozv2 hKJP4P4l3Is7g== Message-ID: <3e03425b-7962-4c69-93aa-96168fd7168e@kernel.org> Date: Thu, 1 Oct 2026 13:40:06 +0200 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 , 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 References: <20260924-fix_split-v8-0-cba7359d882a@arm.com> <20260924-fix_split-v8-3-cba7359d882a@arm.com> <16f16e77-05ab-418e-ad06-8f48fb29375a@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/29/26 12:01, Yeoreum Yun wrote: > 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; > } > I'd leave existing __check_huge() mostly alone, and instead have an additional function that checks the type. Essentially a __check_type() or sth that we run after the large folio / pmd check. -- Cheers, David