From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 566645505C4 for ; Tue, 8 Sep 2026 19:50:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788897029; cv=none; b=Qxv4qq48VHNaPgwM+tIzs9c50gz6eIIROMbCbD6r3AxJ0pBk9BBwGsYgnd7UL4iLTvQ4wW4ovZCRZuOYJ0Zd0ETqBlbbbCmM/qWZOqDX+PKxmVxb1gN2VpPAR6xkwEp+SYRBXeJwr9/KkoFP2P2TDnoVudhC7Acrh1bfce7QkoA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788897029; c=relaxed/simple; bh=N57Z26wf26k1pzzdexfuStYJskwPwaS4cCWY99EhhXk=; h=Date:To:From:Subject:Message-Id; b=miWhBZ/CtR5LqZADFydqpb7zxhYZgvvuJFIvzM5nQ8sJKGZPs8g6nsWylys0osY9qASLghwH+e1f6laWYyr9DFmnDvOkTl15ZoHJwnpU9qKUlYpJtX+bn4D8glIz+SgeG9m/pLpw8LbBDiBDE/RTOEjTrI959+o+DbXXvRzUSbY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=B5HkzU2D; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="B5HkzU2D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 234141F00A3A; Tue, 8 Sep 2026 19:50:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788897022; bh=C7kPMwVQ45ggeEwzhYsvdunnnbV2S+FQSsZs/4uUbrU=; h=Date:To:From:Subject; b=B5HkzU2DGlLt45inw4O0pnO0NRibfMqNPQaSJ33X9w1JRypJNBA33FLZpImMncL/K BhlpzeI2o2UaEl3zV3TQ/eTixlEykJIfnA3h+Q49XihvFjpiFIKHgovZ48gUoygRBh LZuDqQ27OkWRe3LuhgsE9Snh8CG1u4aC8cXPKpOo= Date: Tue, 08 Sep 2026 12:50:21 -0700 To: mm-commits@vger.kernel.org,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-add-folio-order-detection-self-check.patch added to mm-new branch Message-Id: <20260908195022.234141F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/mm: add folio-order detection self-check has been added to the -mm mm-new branch. Its filename is selftests-mm-add-folio-order-detection-self-check.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-add-folio-order-detection-self-check.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "Kiryl Shutsemau (Meta)" Subject: selftests/mm: add folio-order detection self-check Date: Tue, 8 Sep 2026 13:50:55 +0100 The khugepaged mTHP tests detect collapse results with the vm_util folio-order helpers rather than smaps AnonHugePages, which only sees PMD mappings. If those helpers are wrong, every case built on them is wrong the same way, and nothing says so. Check them directly. For every anon THP order the kernel supports, fault memory in with only that order enabled. Require the helpers to classify the backing as exactly that order: not the order below it, and base-page memory as order 0. Run it in the thp category, ahead of ./khugepaged, so a broken helper is reported as itself rather than as a collapse failure. Verified on x86-64 4K (orders 0, 2-9) and arm64 64K (orders 0, 2-13). The test needs ALIGN(), which hmm-tests.c and migration.c each defined privately. Move it to vm_util.h and drop both copies. Assisted-by: LLM Link: https://lore.kernel.org/20260908125105.1510704-10-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Tested-by: Muhammad Usama Anjum Cc: Alexander Gordeev Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes (ARM) Cc: Michal Hocko Cc: Mike Rapoport (Microsoft) Cc: Ryan Roberts Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Usama Arif Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/Makefile | 1 tools/testing/selftests/mm/folio_order_check.c | 122 +++++++++++++++ tools/testing/selftests/mm/hmm-tests.c | 1 tools/testing/selftests/mm/migration.c | 1 tools/testing/selftests/mm/run_vmtests.sh | 2 tools/testing/selftests/mm/vm_util.h | 2 6 files changed, 127 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/folio_order_check.c a/tools/testing/selftests/mm/folio_order_check.c new file mode 100644 --- /dev/null +++ a/tools/testing/selftests/mm/folio_order_check.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Self-check for the vm_util folio-order helpers, is_backed_by_folio() and + * is_range_backed_by_order(), which the khugepaged mTHP cases use to detect + * collapse results. For every anon THP order the kernel supports, fault + * memory in with only that order enabled and require the helpers to report + * exactly that order. + */ +#define _GNU_SOURCE +#include +#include +#include +#include +#include + +#include "kselftest.h" +#include "vm_util.h" +#include "hugepage_settings.h" + +static int pagemap_fd; +static int kpageflags_fd; + +static char *alloc_aligned(size_t size) +{ + size_t len = size * 2; + char *p, *aligned; + + p = mmap(NULL, len, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (p == MAP_FAILED) + ksft_exit_fail_perror("mmap()"); + + aligned = (char *)ALIGN((uintptr_t)p, size); + if (aligned != p) + munmap(p, aligned - p); + if (aligned + size != p + len) + munmap(aligned + size, p + len - aligned - size); + + return aligned; +} + +static void check_order(int order) +{ + struct thp_settings settings = *thp_current_settings(); + size_t size = psize() << order; + bool ok = true; + char *p; + int i; + + for (i = 0; i < NR_ORDERS; i++) + settings.hugepages[i].enabled = THP_NEVER; + if (order) + settings.hugepages[order].enabled = THP_ALWAYS; + thp_push_settings(&settings); + + p = alloc_aligned(size); + *p = 1; + + if (!is_range_backed_by_order(p, size, order, pagemap_fd, kpageflags_fd)) { + ksft_print_msg("order %d not detected after fault\n", order); + ok = false; + } + + /* A lower order must be rejected: the folio is larger */ + if (order && is_range_backed_by_order(p, size, order - 1, + pagemap_fd, kpageflags_fd)) { + ksft_print_msg("order %d also reported as order %d\n", + order, order - 1); + ok = false; + } + + /* A large folio must not pass as order 0 */ + if (order && is_range_backed_by_order(p, size, 0, + pagemap_fd, kpageflags_fd)) { + ksft_print_msg("order %d also reported as order 0\n", order); + ok = false; + } + + munmap(p, size); + thp_pop_settings(); + + ksft_test_result(ok, "order %d classified\n", order); +} + +int main(void) +{ + struct thp_settings settings; + unsigned long orders; + int order; + + ksft_print_header(); + + if (!thp_available()) + ksft_exit_skip("Transparent Hugepages not available\n"); + + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + if (pagemap_fd < 0) + ksft_exit_fail_perror("open(/proc/self/pagemap)"); + kpageflags_fd = open("/proc/kpageflags", O_RDONLY); + if (kpageflags_fd < 0) + ksft_exit_skip("open(/proc/kpageflags) requires root\n"); + + orders = thp_supported_orders(); + if (!orders) + ksft_exit_skip("No supported THP orders\n"); + + ksft_set_plan(__builtin_popcountl(orders) + 1); + + thp_save_settings(); + thp_read_settings(&settings); + /* Base of the settings stack; the bottom entry is never popped */ + thp_push_settings(&settings); + + check_order(0); + for (order = 1; order < NR_ORDERS; order++) { + if (!(orders & (1UL << order))) + continue; + check_order(order); + } + + ksft_finished(); +} --- a/tools/testing/selftests/mm/hmm-tests.c~selftests-mm-add-folio-order-detection-self-check +++ a/tools/testing/selftests/mm/hmm-tests.c @@ -65,7 +65,6 @@ enum { #define HMM_PATH_MAX 64 #define NTIMES 10 -#define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1))) /* Just the flags we need, copied from mm.h: */ #ifndef FOLL_WRITE --- a/tools/testing/selftests/mm/Makefile~selftests-mm-add-folio-order-detection-self-check +++ a/tools/testing/selftests/mm/Makefile @@ -105,6 +105,7 @@ TEST_GEN_FILES += guard-regions TEST_GEN_FILES += merge TEST_GEN_FILES += rmap TEST_GEN_FILES += folio_split_race_test +TEST_GEN_FILES += folio_order_check ifneq ($(ARCH),arm64) TEST_GEN_FILES += soft-dirty --- a/tools/testing/selftests/mm/migration.c~selftests-mm-add-folio-order-detection-self-check +++ a/tools/testing/selftests/mm/migration.c @@ -20,7 +20,6 @@ #define TWOMEG (2<<20) #define RUNTIME (20) -#define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1))) HUGETLB_SETUP_DEFAULT_PAGES(1) --- a/tools/testing/selftests/mm/run_vmtests.sh~selftests-mm-add-folio-order-detection-self-check +++ a/tools/testing/selftests/mm/run_vmtests.sh @@ -367,6 +367,8 @@ CATEGORY="pfnmap" run_test ./pfnmap # COW tests CATEGORY="cow" run_test ./cow +CATEGORY="thp" run_test ./folio_order_check + CATEGORY="thp" run_test ./khugepaged CATEGORY="thp" run_test ./khugepaged -s 2 --- a/tools/testing/selftests/mm/vm_util.h~selftests-mm-add-folio-order-detection-self-check +++ a/tools/testing/selftests/mm/vm_util.h @@ -12,6 +12,8 @@ #include #define BIT_ULL(nr) (1ULL << (nr)) +#define ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1)) + #define PM_SOFT_DIRTY BIT_ULL(55) #define PM_MMAP_EXCLUSIVE BIT_ULL(56) #define PM_UFFD_WP BIT_ULL(57) _ Patches currently in -mm which might be from kas@kernel.org are mm-huge_memory-do-not-touch-frozen-folios-in-deferred_split_isolate.patch mm-huge_memory-dequeue-the-deferred-split-after-the-split-freeze.patch selftests-mm-raise-the-khugepaged-test-case-cap.patch selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large.patch selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch selftests-mm-skip-khugepaged-page-cache-cases-without-a-pmd-folio.patch selftests-mm-make-the-swap-cases-swapout-reliable.patch selftests-mm-stop-khugepaged-during-the-madv_collapse-cases.patch selftests-mm-move-is_backed_by_folio-into-vm_util.patch selftests-mm-add-folio-order-check-for-address-ranges.patch selftests-mm-add-folio-order-detection-self-check.patch selftests-mm-add-khugepaged-completion-barrier-helper.patch selftests-mm-add-order-parameterized-khugepaged-collapse-cases.patch selftests-mm-parameterize-the-mixed-source-collapse-case-by-source-order.patch selftests-mm-cover-a-shared-source-collapse-write-race.patch selftests-mm-run-every-supported-collapse-order-by-default.patch selftests-mm-check-that-one-khugepaged-pass-collapses-one-window.patch selftests-mm-add-khugepaged-race-harness.patch selftests-mm-race-the-collapse-of-windows-with-holes.patch selftests-mm-add-memory-pressure-threads-to-the-khugepaged-race-harness.patch selftests-mm-zap-whole-pte-tables-in-the-khugepaged-race-harness.patch