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 7D59947C102; Mon, 21 Sep 2026 10:40:21 +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=1789987223; cv=none; b=KoYC7bKP3xkf+8I4zVbUzYA4rrKtYQq9OaS60Wke2AeQPNAxYshy6L46eqJDVn6EPKHnm3/wPLeOANOtp3bjZ/NXrzq11MKkCCPzIYsSTguFQe2dwXGiP2D2zuHIZt+ZFpZfHdK1hpMeWKCfLMR2JPfXKi5TOulO93vTRk58gIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789987223; c=relaxed/simple; bh=EdKZk9/jwDQIH8zFOg73ZY28l1qbx+55/Tqq3ekXyzM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Tog97e9IowUzGaOaBTAZP+VOTCdahn68ZAfIyP2LJvI4Zra1PfqAtcbFE9eJwJfMJ8dHpSbHZTM9yVeHxvFtbgk5nb+e3KShJz55WhKbAbWLRwTbNL52q+mY+RfmygBnkDyMKJLlin/myRKIIFEaRYyOZ4hFkqYwXzu3YWEHGZ0= 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=edH+WGXv; 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="edH+WGXv" 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 38BED2F; Mon, 21 Sep 2026 03:40:17 -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 B72DD3F86C; Mon, 21 Sep 2026 03:40:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789987220; bh=EdKZk9/jwDQIH8zFOg73ZY28l1qbx+55/Tqq3ekXyzM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=edH+WGXvFOoqTmFzW/qAYeuRkSbYB6GoWYchgnXWGvg+ykyVLn72hrrdSESDJNbtg SqvbwjgLAhzrP/wucnb1SJNssIUgMhCqFI6kvt7xa91iqxEvl6a9P42itW5mSsEcWt KMinCG5BbLF0Jt7L9zI8coH2iDy5CZEbXUvOUYrE= From: Yeoreum Yun Date: Mon, 21 Sep 2026 11:40:08 +0100 Subject: [PATCH v7 2/3] kselftest: mm: replace usage of /proc/self/smaps for check_huge_xxx() helper 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: <20260921-fix_split-v7-2-d25ec991159f@arm.com> References: <20260921-fix_split-v7-0-d25ec991159f@arm.com> In-Reply-To: <20260921-fix_split-v7-0-d25ec991159f@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, Yeoreum Yun X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7429; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=EdKZk9/jwDQIH8zFOg73ZY28l1qbx+55/Tqq3ekXyzM=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqsQmJmsEaafXH26QPIpE3mc5C7ESbc2MlpKPoS c7L30rdhyKJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCarEJiQAKCRBt1cPRWsUx MzXrC/0TBjJtiyR2c/wJJd55mqoYa7VS2P9VnxgPc6FtQX4KqIXS6rrQ9ffuNCJqGf2TJffEe3x 6NnvLtDZcdMd4iPg6OUy5TZ59DQSlZdLMtiHfrsDi5TKjgqRzy0lFLXJiFYvFl4+Z9Wt0Vsur5i SMEWYViWoEvo/B+mNtThYRUYxReqj08ecc6cdO3pQy5SZ1/4MVVHjyGI5aMg96T1uxuEBHmUWrA MXPVICjJp9DVnCYs71frynxaS3TaZ84c/ooFFU3FUT0q+HPksl5msxvs7KdVGRCv7ZH0qjySf3S tyQmlgdWZUns2U1OVeRsKE3KiFdSd1xZq8LpeiP3OAboubkfBXXp8+HAHSQQ5Afks8R/1rlFyLr jBuRZaOq6PROy6ZPUGKuGyi4o7rsirU50HxLdzGUKQ6WY9xX9GzXwpGTec2HjU4NDkvxbqyFU80 x4CZdTbOT40GThnn17nyNl+rU6L1/ay+tyJgsX8BtpgAMilEQeLn7BQYrMVwiF9NxPjrQ= 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_huge_xxx() 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 and large folios: 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 type of huge page. Since shmem pages are also file-backed, simply check whether the page is file-backed. Suggested-by: David Hildenbrand (Arm) Suggested-by: Zi Yan Signed-off-by: Yeoreum Yun --- tools/testing/selftests/mm/vm_util.c | 137 +++++++++++++++++++++-------------- 1 file changed, 84 insertions(+), 53 deletions(-) diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 4821a35630363..a7c5caf6925e0 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 +378,106 @@ 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) -{ - uint64_t pmd_pagesize = read_pmd_pagesize(); +enum check_huge_type { + CHECK_HUGE_ANON, + CHECK_HUGE_FILE, +}; - if (!pmd_pagesize) - ksft_exit_fail_msg("reading PMD pagesize failed\n"); +static bool check_huge_type(uint64_t categories, uint64_t kpageflags, + enum check_huge_type type) +{ + const bool file = categories & PAGE_IS_FILE; - if (hpage_size == pmd_pagesize) - return __check_pmd_huge(addr, "AnonHugePages: ", nr_hpages, hpage_size); + switch (type) { + case CHECK_HUGE_ANON: + return !file; + case CHECK_HUGE_FILE: + return file; + } - return check_large_folios(addr, len, nr_hpages, hpage_size); + return false; } -bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) +static bool __check_huge(void *addr, size_t len, int nr_hpages, + uint64_t hpage_size, enum check_huge_type type) { - uint64_t pmd_pagesize = read_pmd_pagesize(); + bool ret = false; + int pagemap_fd, kpageflags_fd; + int nr_pmd_mappings = 0; + uint64_t pmd_pagesize, scan_mapping_size; + uint64_t categories, kpf; + 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"); - if (hpage_size == pmd_pagesize) - return __check_pmd_huge(addr, "FilePmdMapped:", nr_hpages, hpage_size); + 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; - return check_large_folios(addr, len, nr_hpages, hpage_size); + pagemap_fd = open(PAGEMAP_PATH, O_RDONLY); + if (pagemap_fd < 0) + ksft_exit_fail_msg("open pagemap fail\n"); + + kpageflags_fd = open(KPAGEFLAGS_PATH, O_RDONLY); + if (kpageflags_fd < 0) + ksft_exit_fail_msg("open kpageflags fail\n"); + + if (!check_pmd_mapping && + !check_large_folios(pagemap_fd, kpageflags_fd, + addr, len, nr_hpages, hpage_size)) + goto out; + + for (; start < end; start += scan_mapping_size) { + categories = pagemap_scan_get_categories(pagemap_fd, start); + pfn = pagemap_get_pfn(pagemap_fd, start); + if (pfn == -1UL) { + if (!allow_nonpresent) + goto out; + else + continue; + } + if (pageflags_get(pfn, kpageflags_fd, &kpf)) + ksft_exit_fail_msg("read kpageflags: %s\n", strerror(errno)); + if (check_pmd_mapping && (categories & PAGE_IS_HUGE)) + nr_pmd_mappings++; + if (kpf & KPF_COMPOUND_TAIL) + continue; + if (!check_huge_type(categories, kpf, type)) + goto out; + } + + if (check_pmd_mapping && (nr_pmd_mappings != nr_hpages)) + goto out; + ret = true; + +out: + close(pagemap_fd); + close(kpageflags_fd); + return ret; } -bool check_huge_shmem(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(); - - if (!pmd_pagesize) - ksft_exit_fail_msg("reading PMD pagesize failed\n"); + return __check_huge(addr, len, nr_hpages, hpage_size, CHECK_HUGE_ANON); +} - if (hpage_size == pmd_pagesize) - return __check_pmd_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size); +bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size) +{ + return __check_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(addr, len, nr_hpages, hpage_size, CHECK_HUGE_FILE); } int64_t allocate_transhuge(void *ptr, int pagemap_fd) -- 2.43.0