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 D87CC3F44EC; Thu, 27 Aug 2026 10:56:27 +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=1787828189; cv=none; b=lH2McXYmlaaRcbv9T31xZuJRYT/lzW9OJrbxkBjHW2PhoSJy+EtuXkg4r/nGXfxQ8vHXwouhLjG1KW5IJO0Ip4HQ+qcCpp0k1XrlLmmCaPaC6On7d8CZm//ygEfusGXh+yXi48hWBzmXPco16YRiQby4knKFY6HnCV++2I8kYuU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787828189; c=relaxed/simple; bh=aeLOKipWhz7t3kYjsBn/bJ0T5mlSlbCPe9WPUdSgV/M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UqFQ5QLpEDVX3U712/uROBT4FWfW+HRb6sYemd585fCFA8hYB1Z5dfZuMb2e61f7x+y/G1Ki0M1ledLdOOovk3WiLk/jISPe1MaLCpTXsJ3rYcowYCg0BpvCwEmXcG3CLCqgeDYLpLpu9OmDOoKXN6BfKPHBMBEPjez838qST9Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hqAkKGTh; 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="hqAkKGTh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 884EE1F000E9; Thu, 27 Aug 2026 10:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787828187; bh=NFSoHGGqxxziGMu2IRcDTRzduPnwUAK7ed4z65urCyM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=hqAkKGThxGJWMDhKFcSqIWlnjHYbdxq1MeNgfjxCRuLwN4q6Unx/ArGi1iZEnVRvu Iv7dJcszqIzAJbFJsWXjHXD1+RsWJUxwC8j5Ks+evINia+X5Ozh67I5DYAQ53x2sA6 ImjOty7oGpySiMZzOvF75EtrAk5qVpXX2dRmif+/T1O+/UGu9i7E+5tmYuVhWNWUxV wbTlrMwiZOTS1625hnk4jnRHRraUo038M1/ftEcQCVtClBMO5Gf4u42PMvrCDsm8nG jGP7E7920p8wsb0FNIMiK5eJs+xLOaIUtwoG3yz1aEZq1G4QC1bOBA7M+Oag9b2hiT 1xm3sIdxFgf9g== Message-ID: <44d36fb6-fdf4-4a8b-8e74-084a4b4f802e@kernel.org> Date: Thu, 27 Aug 2026 12:56:20 +0200 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] kselftest: mm: replace usage of /proc/self/smaps for check_huge_xxx() helper To: Baolin Wang , Yeoreum Yun , Andrew Morton , Lorenzo Stoakes , Zi Yan , "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: <20260826-fix_split-v2-0-71153c7f579a@arm.com> <20260826-fix_split-v2-2-71153c7f579a@arm.com> <0107447a-7c1f-44f8-94fb-109b0f850677@linux.alibaba.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: <0107447a-7c1f-44f8-94fb-109b0f850677@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 8/27/26 10:28, Baolin Wang wrote: > > > On 8/26/26 8:24 PM, 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_huge_xxx() >> helpers incorrectly require the address returned by memalign() to >> match the VMA start address reported in /proc/self/smaps. >> >> Fix this by using /proc/self/pagemap and /proc/kpageflags instead of >> /proc/self/smaps to detect huge pages. >> >> Reported-by: David Hildenbrand (Arm) >> Signed-off-by: Yeoreum Yun >> --- >>   tools/testing/selftests/mm/vm_util.c | 130 ++++++++++++++++++++--------------- >>   tools/testing/selftests/mm/vm_util.h |   1 + >>   2 files changed, 77 insertions(+), 54 deletions(-) >> >> diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/ >> mm/vm_util.c >> index 4821a3563036..1d0959b3b9e8 100644 >> --- a/tools/testing/selftests/mm/vm_util.c >> +++ b/tools/testing/selftests/mm/vm_util.c >> @@ -351,31 +351,13 @@ char *__get_smap_entry(void *addr, const char *pattern, >> char *buf, size_t len) >>       return entry; >>   } >>   -static bool __check_pmd_huge(void *addr, char *pattern, int nr_hpages, >> -          uint64_t hpage_size) >> -{ >> -    char buffer[MAX_LINE_LENGTH]; >> -    uint64_t thp = -1; >> -    char *entry; >> - >> -    entry = __get_smap_entry(addr, pattern, buffer, sizeof(buffer)); >> -    if (!entry) >> -        goto err_out; >> - >> -    if (sscanf(entry, "%9" SCNu64 " kB", &thp) != 1) >> -        ksft_exit_fail_msg("Reading smap error\n"); >> - >> -err_out: >> -    return thp == (nr_hpages * (hpage_size >> 10)); >> -} >> - >> -static bool check_large_folios(void *addr, size_t len, int nr_hpages, >> -        uint64_t hpage_size) >> +static bool check_large_folios(int pagemap_fd, int kpageflags_fd, >> +                   void *addr, size_t len, int nr_hpages, >> +                   uint64_t hpage_size) >>   { >>       int order = 0, pagesize = getpagesize(); >>       unsigned int nr_pages = hpage_size / pagesize; >>       int orders[MAX_NR_ORDERS], status; >> -    int pagemap_fd, kpageflags_fd; >>       bool ret = false; >>         if (!nr_pages) >> @@ -386,15 +368,6 @@ static bool check_large_folios(void *addr, size_t len, >> int nr_hpages, >>           ksft_exit_fail_msg("invalid order\n"); >>         memset(orders, 0, sizeof(int) * MAX_NR_ORDERS); >> -    pagemap_fd = open(PAGEMAP_PATH, O_RDONLY); >> -    if (pagemap_fd == -1) >> -        ksft_exit_fail_msg("read pagemap fail\n"); >> - >> -    kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY); >> -    if (kpageflags_fd == -1) { >> -        close(pagemap_fd); >> -        ksft_exit_fail_msg("read kpageflags fail\n"); >> -    } >>         status = gather_folio_orders(addr, len, pagemap_fd, >>               kpageflags_fd, orders, MAX_NR_ORDERS); >> @@ -405,48 +378,97 @@ static bool check_large_folios(void *addr, size_t len, >> int nr_hpages, >>           ret = true; >>     out: >> -    close(pagemap_fd); >> -    close(kpageflags_fd); >>       return ret; >>   } >>   -bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t >> hpage_size) >> +enum check_huge_type { >> +    CHECK_HUGE_ANON, >> +    CHECK_HUGE_FILE, >> +    CHECK_HUGE_SHMEM, >> +}; >> + >> +static bool __check_pmd_huge(void *addr, size_t len, int nr_hpages, >> +                 uint64_t hpage_size, enum check_huge_type type) > > The original __check_pmd_huge() is only for PMD-sized large folios, but now it > not only checks PMD-sized large folios but also mTHP large folios, which I find > confusing. Please keep its original semantics, and only check PMD-sized large > folios. > >>   { >> -    uint64_t pmd_pagesize = read_pmd_pagesize(); >> +    int pagemap_fd, kpageflags_fd; >> +    uint64_t pmd_pagesize, granule; >> +    uint64_t categories, kpf; >> +    unsigned long pfn; >> +    bool check_large, huge_mapped; >> +    char *start = addr; >> +    char *end = start + len; >>   +    pmd_pagesize = read_pmd_pagesize(); >>       if (!pmd_pagesize) >>           ksft_exit_fail_msg("reading PMD pagesize failed\n"); >>   -    if (hpage_size == pmd_pagesize) >> -        return __check_pmd_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size); >> +    if (nr_hpages > 0) { >> +        check_large = true; >> +        granule = hpage_size; >> +    } else { >> +        check_large = false; >> +        granule = psize(); >> +    } > > This is incorrect for the mTHP large folio check. I already hit a selftest > failure. Please test your patches before sending them out. > > [root@]./khugepaged -c 4 mthp_khugepaged:anon > TAP version 13 > # Save THP and khugepaged settings... OK > 1..4 > # Allocate huge page on fault... OK > # Split huge PMD on MADV_DONTNEED... OK > ok 1 allocate on fault and split > # > # Run test: collapse_full (mthp_khugepaged:anon) > # Collapse multiple fully populated PTE table.... OK > ok 2 collapse_full > # > # Run test: collapse_empty (mthp_khugepaged:anon) > # Do not collapse empty PTE table.... OK > ok 3 collapse_empty > # > # Run test: collapse_single_mthp (mthp_khugepaged:anon) > # Collapse PTE table with half PTE entries present.... Fail > not ok 4 collapse_single_mthp > # Totals: pass:3 fail:1 xfail:0 xpass:0 skip:0 error:0 FWIW, the CI flags this as well: https://github.com/linux-mm/linux-mm/actions/runs/33028595020/job/98375618491 -- Cheers, David