From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: + mm-gup-allow-to-react-to-fatal-signals.patch added to -mm tree Date: Mon, 09 Mar 2020 20:39:17 -0700 Message-ID: <20200310033917.k5Ng5EUq0%akpm@linux-foundation.org> References: <20200305222751.6d781a3f2802d79510941e4e@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:52958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726170AbgCJDjV (ORCPT ); Mon, 9 Mar 2020 23:39:21 -0400 In-Reply-To: <20200305222751.6d781a3f2802d79510941e4e@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: aarcange@redhat.com, bgeffon@google.com, bobbypowers@gmail.com, cracauer@cons.org, david@redhat.com, dgilbert@redhat.com, dplotnikov@virtuozzo.com, gokhale2@llnl.gov, hannes@cmpxchg.org, hughd@google.com, jglisse@redhat.com, kirill@shutemov.name, mcfadden8@llnl.gov, mgorman@suse.de, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, peterx@redhat.com, rppt@linux.vnet.ibm.com, torvalds@linux-foundation.org, willy@infradead.org, xemul@virtuozzo.com The patch titled Subject: mm/gup: allow to react to fatal signals has been added to the -mm tree. Its filename is mm-gup-allow-to-react-to-fatal-signals.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-gup-allow-to-react-to-fatal-signals.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-gup-allow-to-react-to-fatal-signals.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: Peter Xu Subject: mm/gup: allow to react to fatal signals The existing gup code does not react to the fatal signals in many code paths. For example, in one retry path of gup we're still using down_read() rather than down_read_killable(). Also, when doing page faults we don't pass in FAULT_FLAG_KILLABLE as well, which means that within the faulting process we'll wait in non-killable way as well. These were spotted by Linus during the code review of some other patches. Let's allow the gup code to react to fatal signals to improve the responsiveness of threads when during gup and being killed. Link: http://lkml.kernel.org/r/20200220160256.9887-1-peterx@redhat.com Signed-off-by: Peter Xu Cc: Andrea Arcangeli Cc: Bobby Powers Cc: Brian Geffon Cc: David Hildenbrand Cc: Denis Plotnikov Cc: "Dr . David Alan Gilbert" Cc: Hugh Dickins Cc: Jerome Glisse Cc: Johannes Weiner Cc: "Kirill A . Shutemov" Cc: Linus Torvalds Cc: Martin Cracauer Cc: Marty McFadden Cc: Matthew Wilcox Cc: Maya Gokhale Cc: Mel Gorman Cc: Mike Kravetz Cc: Mike Rapoport Cc: Pavel Emelyanov Signed-off-by: Andrew Morton --- mm/gup.c | 12 +++++++++--- mm/hugetlb.c | 3 ++- 2 files changed, 11 insertions(+), 4 deletions(-) --- a/mm/gup.c~mm-gup-allow-to-react-to-fatal-signals +++ a/mm/gup.c @@ -857,7 +857,7 @@ static int faultin_page(struct task_stru if (*flags & FOLL_REMOTE) fault_flags |= FAULT_FLAG_REMOTE; if (locked) - fault_flags |= FAULT_FLAG_ALLOW_RETRY; + fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; if (*flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; if (*flags & FOLL_TRIED) { @@ -1200,7 +1200,7 @@ int fixup_user_fault(struct task_struct address = untagged_addr(address); if (unlocked) - fault_flags |= FAULT_FLAG_ALLOW_RETRY; + fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; retry: vma = find_extend_vma(mm, address); @@ -1322,7 +1322,13 @@ retry: break; *locked = 1; - down_read(&mm->mmap_sem); + ret = down_read_killable(&mm->mmap_sem); + if (ret) { + BUG_ON(ret > 0); + if (!pages_done) + pages_done = ret; + break; + } ret = __get_user_pages(tsk, mm, start, 1, flags | FOLL_TRIED, pages, NULL, locked); --- a/mm/hugetlb.c~mm-gup-allow-to-react-to-fatal-signals +++ a/mm/hugetlb.c @@ -4344,7 +4344,8 @@ long follow_hugetlb_page(struct mm_struc if (flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; if (locked) - fault_flags |= FAULT_FLAG_ALLOW_RETRY; + fault_flags |= FAULT_FLAG_ALLOW_RETRY | + FAULT_FLAG_KILLABLE; if (flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; _ Patches currently in -mm which might be from peterx@redhat.com are mm-gup-rename-nonblocking-to-locked-where-proper.patch mm-gup-fix-__get_user_pages-on-fault-retry-of-hugetlb.patch mm-introduce-fault_signal_pending.patch x86-mm-use-helper-fault_signal_pending.patch arc-mm-use-helper-fault_signal_pending.patch arm64-mm-use-helper-fault_signal_pending.patch powerpc-mm-use-helper-fault_signal_pending.patch sh-mm-use-helper-fault_signal_pending.patch mm-return-faster-for-non-fatal-signals-in-user-mode-faults.patch userfaultfd-dont-retake-mmap_sem-to-emulate-nopage.patch mm-introduce-fault_flag_default.patch mm-introduce-fault_flag_interruptible.patch mm-allow-vm_fault_retry-for-multiple-times.patch mm-gup-allow-vm_fault_retry-for-multiple-times.patch mm-gup-allow-to-react-to-fatal-signals.patch mm-userfaultfd-honor-fault_flag_killable-in-fault-path.patch mm-merge-parameters-for-change_protection.patch userfaultfd-wp-apply-_page_uffd_wp-bit.patch userfaultfd-wp-drop-_page_uffd_wp-properly-when-fork.patch userfaultfd-wp-add-pmd_swp_uffd_wp-helpers.patch userfaultfd-wp-support-swap-and-page-migration.patch khugepaged-skip-collapse-if-uffd-wp-detected.patch userfaultfd-wp-dont-wake-up-when-doing-write-protect.patch userfaultfd-wp-declare-_uffdio_writeprotect-conditionally.patch userfaultfd-selftests-refactor-statistics.patch userfaultfd-selftests-add-write-protect-test.patch