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 981A34C4F79; Thu, 24 Sep 2026 19:11:37 +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=1790277100; cv=none; b=glR7wOfmNQ+J9Cdbj03Cs93csy3RTMKW8qAY8SMazq/5vL8WCbjGm4zyR0iwJ8nXBXSHww+HvL/vQNjr6SZiVDvbIx+0GOKYl5+Ku5Mhwc3Du5n6q29iGgiiPYvDEe3Q5j0rmFB5U9mzbdDV+QoRpWoYXJC7JJxSzvatUmbb4Dg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790277100; c=relaxed/simple; bh=NJ9TsBzPv0Oz4pphqp12ZqEYe9odIvfqK7qCBWhEW7c=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OeMcwMF46EjuP1H05hshPJTVPCkoty3N+y7sTLtNS1N3fT2pp/mQGRGXTBFE4MRC2cXJoBQfnLPXlI1l/YuIG8HRiNo8xhzEXTdtLLuWRX24VrRc9AAoOcbOKu4kLBbnsQpzLnPGlUpbhinMrImZtLRP8cJFD4IiRZMT7FgbrJQ= 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=PTmpeLUu; 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="PTmpeLUu" 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 723ED1E5E; Thu, 24 Sep 2026 12:11:33 -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 90C143F86F; Thu, 24 Sep 2026 12:11:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790277096; bh=NJ9TsBzPv0Oz4pphqp12ZqEYe9odIvfqK7qCBWhEW7c=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=PTmpeLUu4wyIj1VaQQTuEqD6nqge3tOzbX7ZJEZqdDH2SUBv0TNPzoNuP4aFLj8ws NuixyaR/Zh+VrabD50dyp6o5Nde9QnXJq+506g0M4rcRVtyl7BJVoVKo81cD40gWX8 RRNePOKqfC+x7r/TLFVFmUk+xTXjnvFXg/U/swmc= From: Yeoreum Yun Date: Thu, 24 Sep 2026 20:11:17 +0100 Subject: [PATCH v8 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: <20260924-fix_split-v8-2-cba7359d882a@arm.com> References: <20260924-fix_split-v8-0-cba7359d882a@arm.com> In-Reply-To: <20260924-fix_split-v8-0-cba7359d882a@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=5190; i=yeoreum.yun@arm.com; h=from:subject:message-id; bh=NJ9TsBzPv0Oz4pphqp12ZqEYe9odIvfqK7qCBWhEW7c=; b=owEB7QES/pANAwAKAW3Vw9FaxTEzAcsmYgBqtXXc8ibPfv6vH/GOhPDJPfprZtHargXZrqKwL CAek8ul5gqJAbMEAAEKAB0WIQQtg+CS3QUzuFh1pJ1t1cPRWsUxMwUCarV13AAKCRBt1cPRWsUx M6qoC/49e4gLA4pQqDOKPjaqBhxn+g5q+qvt/d44hJ9I+Arzn03Yuoe6sCrJEOTDTbis86jDTIN qn6AUEmWUsmnamdtCWPy/9lc9ZDc87rKcOi8I1hBazFT4QncxIK7i3pO0VGvKLv2StKRyQRKjlo +PUp59Aq2TYvcVTM6k4nqyL1xq1k2vK/DjTBf7d8gArMI57xLzWyTDKDRWs0Ar41NmpqadNnSpU 7BNPwRWlBMINyTIPnjc50oeVpAlYgZ6O+Ty66x/w/cOWSe5yLsEGWRsRijwqzEUvkzuCPUU0t4u F+Ri6/qv/xX2MhniPrP8edl86i2EgOyk8uj4P75mPF1vnUpwbIO4xErnIdVasc0WSjK04Ul8CM7 k6c+fYYwe+QMDfjjrZb68gnTcdHdw/cnCkxFSBSR626PSNXGpvtfPtuPIHhHoLjrAMuYpnJxA0a Ci/nxP4ViurmzAsPs13TohS6XB4nAmN/xONoNXe3ZtUjW6wWIsq+8ql0dLO+uZOlLCi0U= 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 accroding to type of huge page. 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") Suggested-by: David Hildenbrand (Arm) 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..969d7202500c 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_msg("open pagemap fail\n"); + + 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