From nobody Fri Sep 12 09:56:30 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13754C04E69 for ; Thu, 10 Aug 2023 14:30:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235770AbjHJOaN (ORCPT ); Thu, 10 Aug 2023 10:30:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235723AbjHJOaG (ORCPT ); Thu, 10 Aug 2023 10:30:06 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2502BFA for ; Thu, 10 Aug 2023 07:30:06 -0700 (PDT) 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 50B52150C; Thu, 10 Aug 2023 07:30:48 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 937D63F64C; Thu, 10 Aug 2023 07:30:03 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , Matthew Wilcox , Yin Fengwei , David Hildenbrand , Yu Zhao , Catalin Marinas , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain , Itaru Kitayama , "Kirill A. Shutemov" Cc: Ryan Roberts , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 5/5] selftests/mm/cow: Add large anon folio tests Date: Thu, 10 Aug 2023 15:29:42 +0100 Message-Id: <20230810142942.3169679-6-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230810142942.3169679-1-ryan.roberts@arm.com> References: <20230810142942.3169679-1-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add tests similar to the existing THP tests, but which operate on memory backed by large anonymous folios, which are smaller than THP. This reuses all the existing infrastructure. If the test suite detects that large anonyomous folios are not supported by the kernel, the new tests are skipped. Signed-off-by: Ryan Roberts --- tools/testing/selftests/mm/cow.c | 111 +++++++++++++++++++++++++++++-- 1 file changed, 106 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/= cow.c index 304882bf2e5d..932242c965a4 100644 --- a/tools/testing/selftests/mm/cow.c +++ b/tools/testing/selftests/mm/cow.c @@ -33,6 +33,7 @@ static size_t pagesize; static int pagemap_fd; static size_t thpsize; +static size_t lafsize; static int nr_hugetlbsizes; static size_t hugetlbsizes[10]; static int gup_fd; @@ -927,6 +928,42 @@ static void run_with_partial_shared_thp(test_fn fn, co= nst char *desc) do_run_with_large(fn, LARGE_RUN_PARTIAL_SHARED, thpsize); } =20 +static void run_with_laf(test_fn fn, const char *desc) +{ + ksft_print_msg("[RUN] %s ... with large anon folio\n", desc); + do_run_with_large(fn, LARGE_RUN_PTE, lafsize); +} + +static void run_with_laf_swap(test_fn fn, const char *desc) +{ + ksft_print_msg("[RUN] %s ... with swapped-out large anon folio\n", desc); + do_run_with_large(fn, LARGE_RUN_PTE_SWAPOUT, lafsize); +} + +static void run_with_single_pte_of_laf(test_fn fn, const char *desc) +{ + ksft_print_msg("[RUN] %s ... with single PTE of large anon folio\n", desc= ); + do_run_with_large(fn, LARGE_RUN_SINGLE_PTE, lafsize); +} + +static void run_with_single_pte_of_laf_swap(test_fn fn, const char *desc) +{ + ksft_print_msg("[RUN] %s ... with single PTE of swapped-out large anon fo= lio\n", desc); + do_run_with_large(fn, LARGE_RUN_SINGLE_PTE_SWAPOUT, lafsize); +} + +static void run_with_partial_mremap_laf(test_fn fn, const char *desc) +{ + ksft_print_msg("[RUN] %s ... with partially mremap()'ed large anon folio\= n", desc); + do_run_with_large(fn, LARGE_RUN_PARTIAL_MREMAP, lafsize); +} + +static void run_with_partial_shared_laf(test_fn fn, const char *desc) +{ + ksft_print_msg("[RUN] %s ... with partially shared large anon folio\n", d= esc); + do_run_with_large(fn, LARGE_RUN_PARTIAL_SHARED, lafsize); +} + static void run_with_hugetlb(test_fn fn, const char *desc, size_t hugetlbs= ize) { int flags =3D MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB; @@ -1105,6 +1142,14 @@ static void run_anon_test_case(struct test_case cons= t *test_case) run_with_partial_mremap_thp(test_case->fn, test_case->desc); run_with_partial_shared_thp(test_case->fn, test_case->desc); } + if (lafsize) { + run_with_laf(test_case->fn, test_case->desc); + run_with_laf_swap(test_case->fn, test_case->desc); + run_with_single_pte_of_laf(test_case->fn, test_case->desc); + run_with_single_pte_of_laf_swap(test_case->fn, test_case->desc); + run_with_partial_mremap_laf(test_case->fn, test_case->desc); + run_with_partial_shared_laf(test_case->fn, test_case->desc); + } for (i =3D 0; i < nr_hugetlbsizes; i++) run_with_hugetlb(test_case->fn, test_case->desc, hugetlbsizes[i]); @@ -1126,6 +1171,8 @@ static int tests_per_anon_test_case(void) =20 if (thpsize) tests +=3D 8; + if (lafsize) + tests +=3D 6; return tests; } =20 @@ -1680,15 +1727,74 @@ static int tests_per_non_anon_test_case(void) return tests; } =20 +static size_t large_anon_folio_size(void) +{ + /* + * There is no interface to query this. But we know that it must be less + * than thpsize. So we map a thpsize area, aligned to thpsize offset by + * thpsize/2 (to avoid a hugepage being allocated), then touch the first + * page and see how many pages get faulted in. + */ + + int max_order =3D __builtin_ctz(thpsize); + size_t mmap_size =3D thpsize * 3; + char *mmap_mem =3D NULL; + int order =3D 0; + char *mem; + size_t offset; + int ret; + + /* For alignment purposes, we need 2.5x the requested size. */ + mmap_mem =3D mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (mmap_mem =3D=3D MAP_FAILED) + goto out; + + /* Align the memory area to thpsize then offset it by thpsize/2. */ + mem =3D (char *)(((uintptr_t)mmap_mem + thpsize) & ~(thpsize - 1)); + mem +=3D thpsize / 2; + + /* We might get a bigger large anon folio when MADV_HUGEPAGE is set. */ + ret =3D madvise(mem, thpsize, MADV_HUGEPAGE); + if (ret) + goto out; + + /* Probe the memory to see how much is populated. */ + mem[0] =3D 0; + for (order =3D 0; order < max_order; order++) { + offset =3D (1 << order) * pagesize; + if (!pagemap_is_populated(pagemap_fd, mem + offset)) + break; + } + +out: + if (mmap_mem) + munmap(mmap_mem, mmap_size); + + if (order =3D=3D 0) + return 0; + + return offset; +} + int main(int argc, char **argv) { int err; =20 + gup_fd =3D open("/sys/kernel/debug/gup_test", O_RDWR); + pagemap_fd =3D open("/proc/self/pagemap", O_RDONLY); + if (pagemap_fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + pagesize =3D getpagesize(); thpsize =3D read_pmd_pagesize(); if (thpsize) ksft_print_msg("[INFO] detected THP size: %zu KiB\n", thpsize / 1024); + lafsize =3D large_anon_folio_size(); + if (lafsize) + ksft_print_msg("[INFO] detected large anon folio size: %zu KiB\n", + lafsize / 1024); nr_hugetlbsizes =3D detect_hugetlb_page_sizes(hugetlbsizes, ARRAY_SIZE(hugetlbsizes)); detect_huge_zeropage(); @@ -1698,11 +1804,6 @@ int main(int argc, char **argv) ARRAY_SIZE(anon_thp_test_cases) * tests_per_anon_thp_test_case() + ARRAY_SIZE(non_anon_test_cases) * tests_per_non_anon_test_case()); =20 - gup_fd =3D open("/sys/kernel/debug/gup_test", O_RDWR); - pagemap_fd =3D open("/proc/self/pagemap", O_RDONLY); - if (pagemap_fd < 0) - ksft_exit_fail_msg("opening pagemap failed\n"); - run_anon_test_cases(); run_anon_thp_test_cases(); run_non_anon_test_cases(); --=20 2.25.1