From nobody Tue Oct 7 19:55:39 2025 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (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 CE6C421FF5C; Mon, 7 Jul 2025 07:33:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751873638; cv=pass; b=kIi36ws2BC6cHrhg0FC42UniDIoiUdcZ17Rtp1kpKH7oZbpSTBa9iR/stDG1d2++JM5OTeD7T09UBgRz7z03toXaLiiUtuahluw7/ArdBagw+tZKODb5NVtbwST2s9qiZeObKJ4b7d+iWudC57d2JN8DSMpiJwPNtPfIcEGYsA8= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751873638; c=relaxed/simple; bh=wXsTWyd4yYlOsiktiqaiTuUm1qucpLijYl3bq49V17w=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ZILTz21rYqEtwppwi670Th+QQutZuTREtY2wviqtPy82izQ9Z3DbMD5LDDrf0RQVPUBHF7/5vM3YAYFcYXUbXkdiTXAXogdu/4nBzZ27ry3uEIPihJtpeilZyCCIDaS28webEriT22XW0dl54yGuSJfHzOBuOTY0i0DcdttaI50= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=usama.anjum@collabora.com header.b=aJlh81gn; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=usama.anjum@collabora.com header.b="aJlh81gn" ARC-Seal: i=1; a=rsa-sha256; t=1751873620; cv=none; d=zohomail.com; s=zohoarc; b=HTCku5Z4eE+HXVPl3u6T2Czgb3E8BG0hU0FVn/GpZjxuDiW5YetXJMhHfh95kfzxvgNsyN09pPJe0boWmoD0NxCGIfiJD8sfNEDZ82lARDwuG3n9a9X2wwBIVMXry4hfk4pL2iGKt6LAS99IEujqwYdZBmfAZD1N0o1b7Ipv4m8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1751873620; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=BdU2n3YWpibKbpwCxOh1ePuw+qQOxSR0HU9wfR6gAUw=; b=UUtocAbeWAI9mnkKNCOlVjqWdsytG9HMeedJ9kKrctqq7KJ7JkyEu8zd6+ZCVsVoPRUolbhlLonFfNxnXfgI7JoICALTx6KEjDlQnoH9EgwIgNIKjGQmmfhTziS/wEI0anJWqdrK41eEvGD9ggnABvzLtTLp9fYdBbNPPo8LZhE= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=usama.anjum@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1751873620; s=zohomail; d=collabora.com; i=usama.anjum@collabora.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=BdU2n3YWpibKbpwCxOh1ePuw+qQOxSR0HU9wfR6gAUw=; b=aJlh81gnwv0G1WDmGbMUDQMTGB7/sBHhRZLQ/LdDsTfMlJSrQlsII+HOS4H4R+pC +3PxtlCvu3Y0bXGRyk3u09OWv3tMp8ZfX2PPh6zmdtFpmGGufya6lLwCL5EgMZV8zCv XwCHvyPXvLIpvlBqF73giMgeFOZKnBr6oXA06TlY= Received: by mx.zohomail.com with SMTPS id 1751873617320882.1477553147479; Mon, 7 Jul 2025 00:33:37 -0700 (PDT) From: Muhammad Usama Anjum To: Andrew Morton , Shuah Khan Cc: Muhammad Usama Anjum , kernel@collabora.com, David Hildenbrand , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] selftests/mm: pagemap_scan ioctl: add PFN ZERO test cases Date: Mon, 7 Jul 2025 12:33:20 +0500 Message-ID: <20250707073321.106431-1-usama.anjum@collabora.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMailClient: External Content-Type: text/plain; charset="utf-8" Add test cases to test the correctness of PFN ZERO flag of pagemap_scan ioctl. Test with normal pages backed memory and huge pages backed memory. Cc: David Hildenbrand Signed-off-by: Muhammad Usama Anjum --- The bug has been fixed [1]. [1] https://lore.kernel.org/all/20250617143532.2375383-1-david@redhat.com Changes since v1: - Skip if madvise() fails - Skip test if use_zero_page isn't set to 1 - Keep on using memalign()+free() to allocate huge pages Changes sice v2: - Move zero page detection code out to vm_util and use that - Use mmap instead of memalign to allocate hugepage --- tools/testing/selftests/mm/cow.c | 27 +------- tools/testing/selftests/mm/pagemap_ioctl.c | 72 +++++++++++++++++++++- tools/testing/selftests/mm/vm_util.c | 23 +++++++ tools/testing/selftests/mm/vm_util.h | 2 + 4 files changed, 95 insertions(+), 29 deletions(-) diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/= cow.c index b6cfe0a4b7dfd..b26bbf6ec4617 100644 --- a/tools/testing/selftests/mm/cow.c +++ b/tools/testing/selftests/mm/cow.c @@ -72,31 +72,6 @@ static int detect_thp_sizes(size_t sizes[], int max) return count; } =20 -static void detect_huge_zeropage(void) -{ - int fd =3D open("/sys/kernel/mm/transparent_hugepage/use_zero_page", - O_RDONLY); - size_t enabled =3D 0; - char buf[15]; - int ret; - - if (fd < 0) - return; - - ret =3D pread(fd, buf, sizeof(buf), 0); - if (ret > 0 && ret < sizeof(buf)) { - buf[ret] =3D 0; - - enabled =3D strtoul(buf, NULL, 10); - if (enabled =3D=3D 1) { - has_huge_zeropage =3D true; - ksft_print_msg("[INFO] huge zeropage is enabled\n"); - } - } - - close(fd); -} - static bool range_is_swapped(void *addr, size_t size) { for (; size; addr +=3D pagesize, size -=3D pagesize) @@ -1791,7 +1766,7 @@ int main(int argc, char **argv) } nr_hugetlbsizes =3D detect_hugetlb_page_sizes(hugetlbsizes, ARRAY_SIZE(hugetlbsizes)); - detect_huge_zeropage(); + has_huge_zeropage =3D detect_huge_zeropage(); =20 ksft_set_plan(ARRAY_SIZE(anon_test_cases) * tests_per_anon_test_case() + ARRAY_SIZE(anon_thp_test_cases) * tests_per_anon_thp_test_case() + diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/sel= ftests/mm/pagemap_ioctl.c index 57b4bba2b45f3..059c6d5f971e7 100644 --- a/tools/testing/selftests/mm/pagemap_ioctl.c +++ b/tools/testing/selftests/mm/pagemap_ioctl.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 + #define _GNU_SOURCE #include #include @@ -34,8 +35,8 @@ #define PAGEMAP "/proc/self/pagemap" int pagemap_fd; int uffd; -unsigned int page_size; -unsigned int hpage_size; +size_t page_size; +size_t hpage_size; const char *progname; =20 #define LEN(region) ((region.end - region.start)/page_size) @@ -1480,6 +1481,68 @@ static void transact_test(int page_size) extra_thread_faults); } =20 +void zeropfn_tests(void) +{ + unsigned long long mem_size; + struct page_region vec; + int i, ret; + char *mmap_mem, *mem; + + /* Test with normal memory */ + mem_size =3D 10 * page_size; + mem =3D mmap(NULL, mem_size, PROT_READ, MAP_PRIVATE | MAP_ANON, -1, 0); + if (mem =3D=3D MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + + /* Touch each page to ensure it's mapped */ + for (i =3D 0; i < mem_size; i +=3D page_size) + (void)((volatile char *)mem)[i]; + + ret =3D pagemap_ioctl(mem, mem_size, &vec, 1, 0, + (mem_size / page_size), PAGE_IS_PFNZERO, 0, 0, PAGE_IS_PFNZERO); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret =3D=3D 1 && LEN(vec) =3D=3D (mem_size / page_size), + "%s all pages must have PFNZERO set\n", __func__); + + munmap(mem, mem_size); + + /* Test with huge page if user_zero_page is set to 1 */ + if (!detect_huge_zeropage()) { + ksft_test_result_skip("%s use_zero_page not supported or set to 1\n", __= func__); + return; + } + + mem_size =3D 2 * hpage_size; + mmap_mem =3D mmap(NULL, mem_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (mmap_mem =3D=3D MAP_FAILED) + ksft_exit_fail_msg("error nomem\n"); + + /* We need a THP-aligned memory area. */ + mem =3D (char *)(((uintptr_t)mmap_mem + hpage_size) & ~(hpage_size - 1)); + + ret =3D madvise(mem, hpage_size, MADV_HUGEPAGE); + if (!ret) { + char tmp =3D *mem; + + asm volatile("" : "+r" (tmp)); + + ret =3D pagemap_ioctl(mem, hpage_size, &vec, 1, 0, + 0, PAGE_IS_PFNZERO, 0, 0, PAGE_IS_PFNZERO); + if (ret < 0) + ksft_exit_fail_msg("error %d %d %s\n", ret, errno, strerror(errno)); + + ksft_test_result(ret =3D=3D 1 && LEN(vec) =3D=3D (hpage_size / page_size= ), + "%s all huge pages must have PFNZERO set\n", __func__); + } else { + ksft_test_result_skip("%s huge page not supported\n", __func__); + } + + munmap(mmap_mem, mem_size); +} + int main(int __attribute__((unused)) argc, char *argv[]) { int shmid, buf_size, fd, i, ret; @@ -1494,7 +1557,7 @@ int main(int __attribute__((unused)) argc, char *argv= []) if (init_uffd()) ksft_exit_pass(); =20 - ksft_set_plan(115); + ksft_set_plan(117); =20 page_size =3D getpagesize(); hpage_size =3D read_pmd_pagesize(); @@ -1669,6 +1732,9 @@ int main(int __attribute__((unused)) argc, char *argv= []) /* 16. Userfaultfd tests */ userfaultfd_tests(); =20 + /* 17. ZEROPFN tests */ + zeropfn_tests(); + close(pagemap_fd); ksft_exit_pass(); } diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests= /mm/vm_util.c index a36734fb62f38..dde9e8ab4dc46 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -424,3 +424,26 @@ bool check_vmflag_io(void *addr) flags +=3D flaglen; } } + +bool detect_huge_zeropage(void) +{ + int fd =3D open("/sys/kernel/mm/transparent_hugepage/use_zero_page", + O_RDONLY); + bool enabled =3D 0; + char buf[15]; + int ret; + + if (fd < 0) + return 0; + + ret =3D pread(fd, buf, sizeof(buf), 0); + if (ret > 0 && ret < sizeof(buf)) { + buf[ret] =3D 0; + + if (strtoul(buf, NULL, 10) =3D=3D 1) + enabled =3D 1; + } + + close(fd); + return enabled; +} diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests= /mm/vm_util.h index 6effafdc4d8a2..ca4c1f78ce18c 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -74,6 +74,8 @@ int uffd_register_with_ioctls(int uffd, void *addr, uint6= 4_t len, unsigned long get_free_hugepages(void); bool check_vmflag_io(void *addr); =20 +bool detect_huge_zeropage(void); + /* * On ppc64 this will only work with radix 2M hugepage size */ --=20 2.43.0