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 205CE28B4E2; Mon, 28 Sep 2026 12:46:50 +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=1790599611; cv=none; b=hoi2NWxuojt4A2EklcV21fLY/TlMGpekLHZrRRBAU2GxIcQZMBF/8iEiQq4T6YiYQvrnXr6fN488+2vBi+rex9QVdYmMduBra2qDJzBMSD1ugWO1qXDrhXY+CVTgc9M2g82cGyLZu86QZbJgIPAqhYkkQ6OPRAhOsjuhwrFUziI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790599611; c=relaxed/simple; bh=j/Ie592EEbk/T8LZ3R8KHr3py7srcqEXsjGQaHuXjC8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ubn8nc+P3YNraGlpL/OdOqIMWz+cs7myxX1XA2YnogVdScRm4MpvtJNOI7X55qfNJI7gaJ7DLJHoS9wHrhq4g+wHftRPEXFxeIm4Si16rLnZSJdRELItzvmOCZtOQAEpap2qc/Xdq0O3ZZsIbHlxjeu9EdZpXjzlFx11CROspos= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CLO2FB68; 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="CLO2FB68" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FADD1F000FF; Mon, 28 Sep 2026 12:46:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790599610; bh=sPyOk5nBUF/LDpjxx5RQ1YM9nnmqTs1Y+tPLkniResQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=CLO2FB68h13oONS0tCxT3nzpBarQ0IMXTNE8i/vtr+wdvHrdlshJxeAaSf2Vy7ANY vO23AracXVaObH4KAm+tkNctqZOp8360QJq2izxto2xDz2CkjdzYaoaINh/58bZ4WS p7DJh28paTWK/aQpKNmO3Zp+zCa4+mtkgDnnoiG9hWxIRcRRa40VkhWbl+T5Lih4Qp dfuZT0UdAhUvgQCCSCNpjgzIdT5lS0QZHkHkFkF+buuW711LVx6MRCCVEKzG1jjE3s CQ/HDjkO/BlH3+9QMoMpKI2A8plwtDPG6LYLf+bHNHmHUNoBy6mN+Y3J6uXoV+EwYS JZExNChDtc8vA== Message-ID: <8c4ffa3e-4ce6-4b0b-a2e0-08d710c54522@kernel.org> Date: Mon, 28 Sep 2026 14:46:40 +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 2/4] kselftest: mm: replace usage of /proc/self/smaps for __check_pmd_huge() To: Yeoreum Yun , Sarthak Sharma Cc: 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-v8-2-cba7359d882a@arm.com> 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: 8bit On 9/25/26 16:23, Yeoreum Yun wrote: > On Fri, Sep 25, 2026 at 06:08:44PM +0530, Sarthak Sharma wrote: >> >> >> On 9/25/26 12:41 AM, Yeoreum Yun wrote: >>> Since glibc commit 321e1fc73f (“malloc: Enable 2MB THP by default on AArch64”), >>> glibc may call madvise(MADV_HUGEPAGE) for sufficiently large allocations >>> made by memalign(). >>> >>> The underlying VMA may start at a different address from the aligned >>> address returned by memalign(). Furthermore, a subsequent >>> madvise(MADV_HUGEPAGE) call does not split the VMA because the flag is >>> already set. >>> >>> This causes split_huge_page_test to fail because the check_pmd_huge() >>> helpers incorrectly require the address returned by memalign() to >>> match the VMA start address reported in /proc/self/smaps. >>> >>> Instead of relying on /proc/self/smaps, use /proc/self/pagemap and >>> /proc/kpageflags to detect huge-page mappings checking PAGE_IS_HUGE >>> and PAGE_IS_FILE accroding to type of huge page. >> >> s/accroding/according > > Okay. > >> >>> >>> Since shmem pages are also file-backed, simply check whether the page >>> is file-backed. >>> >>> Fixes: 642bc52aed9 ("selftests: vm: bring common functions to a new file") >> >> Checkpatch gives a warning saying it requires atleast 12 characters of >> commit SHA. > > Oops. I'll update. > >> >>> Suggested-by: David Hildenbrand (Arm) >>> Signed-off-by: Yeoreum Yun >>> --- >> >> [...] >> >>> +static bool __check_pmd_huge(void *addr, size_t len, int nr_hpages, >>> + uint64_t hpage_size, enum check_huge_type type) >>> +{ >>> + int pagemap_fd; >>> + int nr_pmd_mappings = 0; >>> + uint64_t categories; >>> + char *start = addr; >>> + char *end = start + len; >>> + >>> + pagemap_fd = open(PAGEMAP_PATH, O_RDONLY); >>> + if (pagemap_fd < 0) >>> + ksft_exit_fail_msg("open pagemap fail\n"); >> >> Can we use ksft_exit_fail_perror("open pagemap") here? Will help in >> diagnosing failures as well. > > I see thanks! > > >> >> Apart from these nits, rest looks good. >> >> Reviewed-by: Sarthak Sharma > With these things Acked-by: David Hildenbrand (Arm) Thanks Sarthak for the review! -- Cheers, David