From mboxrd@z Thu Jan 1 00:00:00 1970 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 0A449C433EF for ; Thu, 31 Mar 2022 04:32:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229478AbiCaEe3 (ORCPT ); Thu, 31 Mar 2022 00:34:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbiCaEeY (ORCPT ); Thu, 31 Mar 2022 00:34:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1A101FA42 for ; Wed, 30 Mar 2022 21:32:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6EFD361416 for ; Thu, 31 Mar 2022 04:32:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1F7AC340ED; Thu, 31 Mar 2022 04:32:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648701156; bh=kgB8L9Xuk3a5jK567WDar+IgZqgONDyAs4PlWTWgtmk=; h=Date:To:From:Subject:From; b=jhWmpdVmchC1l/qLNB1lE59yRY5ppl+lO9GfyLXGAkkNPMU+U/ZJRgBLSLQxuW4BT ISku6R9K0g/hVevTyXp123Eo412kYjLvX7Tt4NimjAVA6DyAR/cyD1VOzf9Fc8JKYp fsgVqciwBUMODRi52gHY/jUY0nQMBH1xxDPZRy0Q= Date: Wed, 30 Mar 2022 21:32:36 -0700 To: mm-commits@vger.kernel.org, zhangliang5@huawei.com, willy@infradead.org, vbabka@suse.cz, shy828301@gmail.com, shakeelb@google.com, rppt@linux.ibm.com, rientjes@google.com, riel@surriel.com, peterx@redhat.com, pedrodemargomes@gmail.com, oleg@redhat.com, oded.gabbay@gmail.com, namit@vmware.com, mike.kravetz@oracle.com, mhocko@kernel.org, kirill.shutemov@linux.intel.com, khalid.aziz@oracle.com, jhubbard@nvidia.com, jgg@nvidia.com, jannh@google.com, jack@suse.cz, hughd@google.com, hch@lst.de, guro@fb.com, ddutile@redhat.com, aarcange@redhat.com, david@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range.patch added to -mm tree Message-Id: <20220331043236.C1F7AC340ED@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/hugetlb: take src_mm->write_protect_seq in copy_hugetlb_page_range() has been added to the -mm tree. Its filename is mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: David Hildenbrand Subject: mm/hugetlb: take src_mm->write_protect_seq in copy_hugetlb_page_range() Let's do it just like copy_page_range(), taking the seqlock and making sure the mmap_lock is held in write mode. This allows for add a VM_BUG_ON to page_needs_cow_for_dma() and properly synchronizes cocnurrent fork() with GUP-fast of hugetlb pages, which will be relevant for further changes. Link: https://lkml.kernel.org/r/20220329160440.193848-3-david@redhat.com Signed-off-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: David Rientjes Cc: Don Dutile Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: Khalid Aziz Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton --- include/linux/mm.h | 4 ++++ mm/hugetlb.c | 8 ++++++-- 2 files changed, 10 insertions(+), 2 deletions(-) --- a/include/linux/mm.h~mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range +++ a/include/linux/mm.h @@ -1576,6 +1576,8 @@ static inline bool page_maybe_dma_pinned /* * This should most likely only be called during fork() to see whether we * should break the cow immediately for a page on the src mm. + * + * The caller has to hold the PT lock and the vma->vm_mm->->write_protect_seq. */ static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma, struct page *page) @@ -1583,6 +1585,8 @@ static inline bool page_needs_cow_for_dm if (!is_cow_mapping(vma->vm_flags)) return false; + VM_BUG_ON(!(raw_read_seqcount(&vma->vm_mm->write_protect_seq) & 1)); + if (!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)) return false; --- a/mm/hugetlb.c~mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range +++ a/mm/hugetlb.c @@ -4717,6 +4717,8 @@ int copy_hugetlb_page_range(struct mm_st vma->vm_start, vma->vm_end); mmu_notifier_invalidate_range_start(&range); + mmap_assert_write_locked(src); + raw_write_seqcount_begin(&src->write_protect_seq); } else { /* * For shared mappings i_mmap_rwsem must be held to call @@ -4849,10 +4851,12 @@ again: spin_unlock(dst_ptl); } - if (cow) + if (cow) { + raw_write_seqcount_end(&src->write_protect_seq); mmu_notifier_invalidate_range_end(&range); - else + } else { i_mmap_unlock_read(mapping); + } return ret; } _ Patches currently in -mm which might be from david@redhat.com are mm-rmap-fix-missing-swap_free-in-try_to_unmap-after-arch_unmap_one-failed.patch mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range.patch mm-memory-slightly-simplify-copy_present_pte.patch mm-rmap-split-page_dup_rmap-into-page_dup_file_rmap-and-page_try_dup_anon_rmap.patch mm-rmap-convert-rmap-flags-to-a-proper-distinct-rmap_t-type.patch mm-rmap-remove-do_page_add_anon_rmap.patch mm-rmap-pass-rmap-flags-to-hugepage_add_anon_rmap.patch mm-rmap-drop-compound-parameter-from-page_add_new_anon_rmap.patch mm-rmap-use-page_move_anon_rmap-when-reusing-a-mapped-pageanon-page-exclusively.patch mm-huge_memory-remove-outdated-vm_warn_on_once_page-from-unmap_page.patch mm-page-flags-reuse-pg_mappedtodisk-as-pg_anon_exclusive-for-pageanon-pages.patch mm-remember-exclusively-mapped-anonymous-pages-with-pg_anon_exclusive.patch mm-gup-disallow-follow_pagefoll_pin.patch mm-support-gup-triggered-unsharing-of-anonymous-pages.patch mm-gup-trigger-fault_flag_unshare-when-r-o-pinning-a-possibly-shared-anonymous-page.patch mm-gup-sanity-check-with-config_debug_vm-that-anonymous-pages-are-exclusive-when-unpinning.patch mm-swap-remember-pg_anon_exclusive-via-a-swp-pte-bit.patch mm-debug_vm_pgtable-add-tests-for-__have_arch_pte_swp_exclusive.patch x86-pgtable-support-__have_arch_pte_swp_exclusive.patch arm64-pgtable-support-__have_arch_pte_swp_exclusive.patch s390-pgtable-cleanup-description-of-swp-pte-layout.patch s390-pgtable-support-__have_arch_pte_swp_exclusive.patch powerpc-pgtable-remove-_page_bit_swap_type-for-book3s.patch powerpc-pgtable-support-__have_arch_pte_swp_exclusive-for-book3s.patch