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 9C0241C75F9 for ; Fri, 2 Oct 2026 00:37:41 +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=1790901463; cv=none; b=JZlXmHSWQaZVwwT0Jlmp8/lkZLuAUgqA0m9ZJcmQVng1X/FhzwkVXH55D2i3bGytvFNAIDx0BHr1mhpefcX1sm70crdbjgmS+8m4JKFA1YXCCFlECdvnM6KL380O6CNs2EkQ3vhpmiZf/Mqfiq9TPOh69hVOpgZ7nu9a4ZSf2As= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790901463; c=relaxed/simple; bh=MQMVBj7PfeCwAFVg6systb/1ND3ML48dVoSteWC4Io0=; h=Date:To:From:Subject:Message-Id; b=jHgUVEP2hohVB37U957PWpy3iPvCQThSbGaGe0pynpv2Q+ILy1o3qbd+JLRt8oifjAwkG+046jMW/vAF5f54OnEWt28fGdx6Lbj0uxOv/cZQs/x0XKKeeYfDgZVslWzyibXPL+UzYdLe9rsmYdyHNPJSnIts8T87TFJfYxcxBW8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=E+t0hny0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="E+t0hny0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 410BF1F000FF; Fri, 2 Oct 2026 00:37:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790901461; bh=KLP3lSu8+jKhMzcNVKydt8OM+8IBmvNqzktCZRFAOxs=; h=Date:To:From:Subject; b=E+t0hny0iB9aXMAndmz20zKMoruinpf8OTjXr1PW0kQO/k470adz2CKmZQqOIjoiC vbtmArg4YO0yM+nlPpglKhhArllJQWhcDLgKcmup6vkVqbFRLjV/cK7ZbtsFekIbnR LWw9xbKG29bIeWglE67EshLsz50/LPunk0T3uxx8= Date: Thu, 01 Oct 2026 17:37:40 -0700 To: mm-commits@vger.kernel.org,yeoreum.yun@arm.com,akpm@linux-foundation.org From: Andrew Morton Subject: + kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge.patch added to mm-unstable branch Message-Id: <20261002003741.410BF1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: kselftest: mm: replace usage of /proc/self/smaps for __check_pmd_huge() has been added to the -mm mm-unstable branch. Its filename is kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Yeoreum Yun Subject: kselftest: mm: replace usage of /proc/self/smaps for __check_pmd_huge() Date: Thu, 01 Oct 2026 22:17:52 +0100 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 according to type of huge page. Since shmem pages are also file-backed, simply check whether the page is file-backed. Link: https://lore.kernel.org/20261001-fix_split-v9-2-0f4ba8bbdbdf@arm.com Fixes: 642bc52aed9c ("selftests: vm: bring common functions to a new file") Signed-off-by: Yeoreum Yun Signed-off-by: Andrew Morton Suggested-by: David Hildenbrand (Arm) Reviewed-by: Sarthak Sharma Reviewed-by: Baolin Wang Acked-by: David Hildenbrand (Arm) Tested-by: Baolin Wang Cc: Lorenzo Stoakes Cc: Zi Yan Cc: Liam R. Howlett Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lance Yang Cc: Usama Arif Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Shuah Khan Cc: Kevin Brodsky --- tools/testing/selftests/mm/vm_util.c | 78 +++++++++++++++---------- 1 file changed, 49 insertions(+), 29 deletions(-) --- a/tools/testing/selftests/mm/vm_util.c~kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge +++ a/tools/testing/selftests/mm/vm_util.c @@ -351,24 +351,6 @@ err_out: 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) { @@ -410,20 +392,51 @@ out: 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, +}; + +static bool check_huge_type(uint64_t categories, enum check_huge_type type) { - uint64_t pmd_pagesize = read_pmd_pagesize(); + const bool file = categories & PAGE_IS_FILE; - if (!pmd_pagesize) - ksft_exit_fail_msg("reading PMD pagesize failed\n"); + switch (type) { + case CHECK_HUGE_ANON: + return !file; + case CHECK_HUGE_FILE: + return file; + } - if (hpage_size == pmd_pagesize) - return __check_pmd_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size); + return false; +} - return check_large_folios(addr, len, nr_hpages, hpage_size); +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_perror("open pagemap"); + + for (; start < end; start += hpage_size) { + categories = pagemap_scan_get_categories(pagemap_fd, start); + if (!(categories & PAGE_IS_HUGE)) + continue; + if (check_huge_type(categories, type)) + nr_pmd_mappings++; + } + close(pagemap_fd); + + return nr_hpages == nr_pmd_mappings; } -bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) +bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) { uint64_t pmd_pagesize = read_pmd_pagesize(); @@ -431,12 +444,13 @@ bool check_huge_file(void *addr, size_t ksft_exit_fail_msg("reading PMD pagesize failed\n"); if (hpage_size == pmd_pagesize) - return __check_pmd_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size); + return __check_pmd_huge(addr, len, nr_hpages, hpage_size, + CHECK_HUGE_ANON); return check_large_folios(addr, len, nr_hpages, hpage_size); } -bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) +bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) { uint64_t pmd_pagesize = read_pmd_pagesize(); @@ -444,11 +458,17 @@ bool check_huge_shmem(void *addr, size_t ksft_exit_fail_msg("reading PMD pagesize failed\n"); if (hpage_size == pmd_pagesize) - return __check_pmd_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size); + return __check_pmd_huge(addr, len, nr_hpages, hpage_size, + CHECK_HUGE_FILE); return check_large_folios(addr, len, nr_hpages, hpage_size); } +bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) +{ + return check_huge_file(addr, len, nr_hpages, hpage_size); +} + int64_t allocate_transhuge(void *ptr, int pagemap_fd) { uint64_t ent[2]; _ Patches currently in -mm which might be from yeoreum.yun@arm.com are kselftest-mm-fix-potential-failure-for-merged-vma-in-guard-regions.patch kselftest-mm-remove-exclusion-of-building-soft-dirty-test-in-arm64.patch kselftest-mm-return-fail-when-child-test-result-is-fail-in-khugepaged.patch kselftest-mm-fix-intermittent-failure-khugepaged-test.patch kselftest-mm-prevent-random-failure-of-huge-page-split-for-khugepaged.patch kselftest-mm-replace-usage-of-proc-self-smaps-for-__check_pmd_huge.patch kselftest-mm-integrate-huge-page-checks.patch kselftest-mm-remove-check_huge_shmem.patch