From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7B0651CD33 for ; Thu, 22 Feb 2024 23:27:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708644475; cv=none; b=TSp/lrwVYkgTcJ+yMjWeXUHeLw9K4Y/sjwcBU/k2K2O4MJ2W5Cme1XFyog94SoaTTPxMRgibB1NGv2MdrMOotgN9sKzGdNSUMEszNQENaIE/ZhiByfAno94rh7mYB+fwAYSs/9cXxMPeb/xwNvkUEDuHkgElNK55nFCaaFd9zC8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708644475; c=relaxed/simple; bh=tYvtJo4zQXkDCy+RP1kG9vejYd/nooeKtslEn4kI8HQ=; h=Date:To:From:Subject:Message-Id; b=WMOBqVgoZh+jXE89rI+dxu/k6+Nqa8JeKijNdjGzGXLmd+4YpIleHgA4VjiZXWeJAUMlQRVmNHz4mcfblSO9qSI5wwD3f0OhoKpa0HwE/KSqYFvtId+Z0sgVAScjkjYIbgQi7uUsFo33vlavkx6JNyut1OSdf/8C6/oeEI85PWM= 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=M1+vrefu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="M1+vrefu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 04D2CC43390; Thu, 22 Feb 2024 23:27:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1708644475; bh=tYvtJo4zQXkDCy+RP1kG9vejYd/nooeKtslEn4kI8HQ=; h=Date:To:From:Subject:From; b=M1+vrefu4mLjA8gd1wtz19cpJ+BuR8k05YnVUHuvXgrl+wQz2t/6xvyIX+Bv6h/kS Z9jI9pPxCHjZqk+0mNUz4855zxm47SUQkL+l9MXSVHPHOSkv9DFsGvuZG7ZJJuiXbn YVHmKlRmrPamShqZOxVSLaasLH6oQyQJWHF+mdNU= Date: Thu, 22 Feb 2024 15:27:54 -0800 To: mm-commits@vger.kernel.org,willy@infradead.org,will@kernel.org,svens@linux.ibm.com,ryan.roberts@arm.com,peterz@infradead.org,npiggin@gmail.com,naveen.n.rao@linux.ibm.com,mpe@ellerman.id.au,mhocko@suse.com,hca@linux.ibm.com,gor@linux.ibm.com,fengwei.yin@intel.com,christophe.leroy@csgroup.eu,catalin.marinas@arm.com,borntraeger@linux.ibm.com,arnd@arndb.de,aneesh.kumar@linux.ibm.com,agordeev@linux.ibm.com,david@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-memory-handle-page-case-in-zap_present_pte-separately.patch removed from -mm tree Message-Id: <20240222232755.04D2CC43390@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/memory: handle !page case in zap_present_pte() separately has been removed from the -mm tree. Its filename was mm-memory-handle-page-case-in-zap_present_pte-separately.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: David Hildenbrand Subject: mm/memory: handle !page case in zap_present_pte() separately Date: Wed, 14 Feb 2024 21:44:27 +0100 We don't need uptodate accessed/dirty bits, so in theory we could replace ptep_get_and_clear_full() by an optimized ptep_clear_full() function. Let's rely on the provided pte. Further, there is no scenario where we would have to insert uffd-wp markers when zapping something that is not a normal page (i.e., zeropage). Add a sanity check to make sure this remains true. should_zap_folio() no longer has to handle NULL pointers. This change replaces 2/3 "!page/!folio" checks by a single "!page" one. Note that arch_check_zapped_pte() on x86-64 checks the HW-dirty bit to detect shadow stack entries. But for shadow stack entries, the HW dirty bit (in combination with non-writable PTEs) is set by software. So for the arch_check_zapped_pte() check, we don't have to sync against HW setting the HW dirty bit concurrently, it is always set. Link: https://lkml.kernel.org/r/20240214204435.167852-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Ryan Roberts Cc: Alexander Gordeev Cc: Aneesh Kumar K.V Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Christophe Leroy Cc: Heiko Carstens Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: Michal Hocko Cc: "Naveen N. Rao" Cc: Nicholas Piggin Cc: Peter Zijlstra (Intel) Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Will Deacon Cc: Yin Fengwei Signed-off-by: Andrew Morton --- mm/memory.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) --- a/mm/memory.c~mm-memory-handle-page-case-in-zap_present_pte-separately +++ a/mm/memory.c @@ -1499,10 +1499,6 @@ static inline bool should_zap_folio(stru if (should_zap_cows(details)) return true; - /* E.g. the caller passes NULL for the case of a zero folio */ - if (!folio) - return true; - /* Otherwise we should only zap non-anon folios */ return !folio_test_anon(folio); } @@ -1540,24 +1536,28 @@ static inline void zap_present_pte(struc int *rss, bool *force_flush, bool *force_break) { struct mm_struct *mm = tlb->mm; - struct folio *folio = NULL; bool delay_rmap = false; + struct folio *folio; struct page *page; page = vm_normal_page(vma, addr, ptent); - if (page) - folio = page_folio(page); + if (!page) { + /* We don't need up-to-date accessed/dirty bits. */ + ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm); + arch_check_zapped_pte(vma, ptent); + tlb_remove_tlb_entry(tlb, pte, addr); + VM_WARN_ON_ONCE(userfaultfd_wp(vma)); + ksm_might_unmap_zero_page(mm, ptent); + return; + } + folio = page_folio(page); if (unlikely(!should_zap_folio(details, folio))) return; ptent = ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm); arch_check_zapped_pte(vma, ptent); tlb_remove_tlb_entry(tlb, pte, addr); zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); - if (unlikely(!page)) { - ksm_might_unmap_zero_page(mm, ptent); - return; - } if (!folio_test_anon(folio)) { if (pte_dirty(ptent)) { _ Patches currently in -mm which might be from david@redhat.com are