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 5A6D648FF9D; Thu, 1 Oct 2026 21:18:14 +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=1790889496; cv=none; b=oH61zVYozt3T3GB7/gq7Sjpz6gIxhSer0HZmYEq2+zRCoVvqHfZEx0QyEkwvGh75WeBE5VF93gJ5VbL3JOSYM1sXue4UytSRNHNzSRkgImSDd8wP2uyBjQ7bXGX6v35utd2vUmq3HKFgGk/W57yUnwYoNipKV3VPO8LoaWq1nSM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790889496; c=relaxed/simple; bh=0FkiYTXFXeX4ri5wwdo8r1zDswEVykTKGJ/AokRyxDI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=HzGIsQd+pY5112rmABFKOnBU5hNy8BQnsgVIyPaAxQ7pmh2aFebXMWr+TetgCo5Q8Kj3yG+akiLbXcAdiMD9bf4z6Hbvv452IkDZUz99Pn+A40simCAdL4LmE9ApLPRMUk6DKdSXnDSyYwZclsMXhm4twbDrAj3DVZHpB3mf8X4= 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=Auk2Sz0w; 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="Auk2Sz0w" 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 BA94816F8; Thu, 1 Oct 2026 14:18:09 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 32B523F86F; Thu, 1 Oct 2026 14:18:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790889493; bh=0FkiYTXFXeX4ri5wwdo8r1zDswEVykTKGJ/AokRyxDI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Auk2Sz0wlnW2YUzEY0seFkGbJtuNi1gVERWfk1nWrvIGwydkd0ze+4yC7No5n9Hrs YcfmL9hJPAycP3USSkPccQsJgnPppfjoZm9ogF5zCfZgS8GluLWQW+1KG795zQxUf/ W++hd50w9IDH1vTSsjde/uqUjF+jVWV3s7aVCm18= From: Yeoreum Yun Date: Thu, 01 Oct 2026 22:17:52 +0100 Subject: [PATCH v9 2/4] kselftest: mm: replace usage of /proc/self/smaps for __check_pmd_huge() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20261001-fix_split-v9-2-0f4ba8bbdbdf@arm.com> References: <20261001-fix_split-v9-0-0f4ba8bbdbdf@arm.com> In-Reply-To: <20261001-fix_split-v9-0-0f4ba8bbdbdf@arm.com> To: 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, Sarthak Sharma , Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5409; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=0FkiYTXFXeX4ri5wwdo8r1zDswEVykTKGJ/AokRyxDI=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqvs4KSeP0+3vmIoY7ipzOig2DXg9K5T69uM/ce ct6vjHjeXmJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCar7OCgAKCRBt1cPRWsUx M+JSDACCs32nf3pXyJRxfH9fUKZQ/1LzPeB55JxBVFBp76w2DM2vT/dT+1ThPa11jqosHEDplOQ MCS73R5MY6W3PS4MlSJgGigd5WeOH2+JP9+Irq8E5lh4jwBicNIb8qMtSfvsxMKRIM/KVZfXDIW hCnpPtMfwt1CFySYkVsXZ6SNvun9hbpBJuEtreAAK+TQVMKUZveZMXtSyTC6542Rm8lls5EidLx F03Zh+sRXnnk8rJ+xCZh594Zm7WrXgzZnrRFKBpi5JARwnQQQxJvsSU1kk/eLh578xF0aWuNCp6 4fGtlWE9YPBFEHBM+hNk1bZH4iBimqCKy7+PCxpNBKp8U91/QY1yE3noAkn2x+AwDTml08z4wcs ok1MWeX5zlnM+s4+fJh/xkLtBcLdEiCie/rpPCEdRW91dgmbQ5/gfE2Sf+jr42oNhz0+9BtYOwh ou2LXpKXyeW283K8m6aQ1FZU4rNLRossrMztqx2+XTQGz22DdrOwHaGAf0Kiopoda4APM= X-Developer-Key: i=yeoreum.yun@arm.com; a=openpgp; fpr=2D83E092DD0533B85875A49D6DD5C3D15AC53133 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. Fixes: 642bc52aed9c ("selftests: vm: bring common functions to a new file") Suggested-by: David Hildenbrand (Arm) Reviewed-by: Sarthak Sharma Reviewed-by: Baolin Wang Acked-by: David Hildenbrand (Arm) Tested-by: Baolin Wang Signed-off-by: Yeoreum Yun --- tools/testing/selftests/mm/vm_util.c | 78 ++++++++++++++++++++++-------------- 1 file changed, 49 insertions(+), 29 deletions(-) diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index a0ab78ceedb1..a3c3a2706c22 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -351,24 +351,6 @@ 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) { @@ -410,20 +392,51 @@ static bool check_large_folios(void *addr, size_t len, int nr_hpages, 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 len, int nr_hpages, uint64_t hpage_size) 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 len, int nr_hpages, uint64_t hpage_size 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]; -- 2.43.0