From patchwork Mon Jan 22 19:41:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13526166 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DCE9DC47DD3 for ; Mon, 22 Jan 2024 19:43:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WiYKcSnbjqKxgmw5hOeOgYcYnS20riIF6+GsNvZflNg=; b=ORLNB35Js/wMVN ifQmEOvICu8ibrMk4ODoqxDIRmeArTDo7Y1ozjrnxgWXurLzBXsGazHYAbw0rA13Pi3FzZ58D7DBM MdW7RoVgSJyeklx4s2VRg9h2kXNx0NVCIs7Vapz2X2qyYbhbK80NqnqQl0cOv7Psu1AvPRC5rOS+i kJlPuwR8zzaDVZ6t0pzAPnFg9vwPxfwlfZCvYRpc1v5n9AOec986KxWvI7Y1OsOfQlHMwYm81OREr dm7+O/RVW3QhIxBmtjQ7QXWFDB7qqGdyq50wJ01CF0oE0YV0XGpO4fG3Rk4KtSZOSh0IdE4BIZvkt 3RzXV3aEDSlm2FanhWHw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rS0CS-00DlbD-2G; Mon, 22 Jan 2024 19:43:16 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rS0C7-00DlEC-0s for linux-riscv@lists.infradead.org; Mon, 22 Jan 2024 19:42:57 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1705952574; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aezdbNXr3jeNg/oq4Ir7c4pnUJMPrBPlV8tZyKwBKMo=; b=MrTKK64T88m5kupzcmHFWXEjBQ24brDysIgsk6AJMdcMn+PpKMa9hcUjFkyJ4v6IR+JW/Y nsJwW1djIwvH++bOTuoWpllrXMd4dgQWtAh3QoKz2dzHgmfrKoce0fLBEYTNLkJGpoRsxO a6YHtWwMJq++IyEpvZEEqw4virssRIQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-284-dLhPkRjVM62_BryuXLzoyw-1; Mon, 22 Jan 2024 14:42:48 -0500 X-MC-Unique: dLhPkRjVM62_BryuXLzoyw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 175DA3806063; Mon, 22 Jan 2024 19:42:47 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.195.114]) by smtp.corp.redhat.com (Postfix) with ESMTP id B54363C2E; Mon, 22 Jan 2024 19:42:41 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , Matthew Wilcox , Ryan Roberts , Russell King , Catalin Marinas , Will Deacon , Dinh Nguyen , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , "David S. Miller" , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org Subject: [PATCH v1 07/11] mm/memory: factor out copying the actual PTE in copy_present_pte() Date: Mon, 22 Jan 2024 20:41:56 +0100 Message-ID: <20240122194200.381241-8-david@redhat.com> In-Reply-To: <20240122194200.381241-1-david@redhat.com> References: <20240122194200.381241-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240122_114255_424881_0FF74CED X-CRM114-Status: GOOD ( 17.36 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Let's prepare for further changes. Signed-off-by: David Hildenbrand Reviewed-by: Ryan Roberts --- mm/memory.c | 60 ++++++++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 28 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 7e1f4849463aa..2aa2051ee51d3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -930,6 +930,29 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma return 0; } +static inline void __copy_present_pte(struct vm_area_struct *dst_vma, + struct vm_area_struct *src_vma, pte_t *dst_pte, pte_t *src_pte, + pte_t pte, unsigned long addr) +{ + struct mm_struct *src_mm = src_vma->vm_mm; + + /* If it's a COW mapping, write protect it both processes. */ + if (is_cow_mapping(src_vma->vm_flags) && pte_write(pte)) { + ptep_set_wrprotect(src_mm, addr, src_pte); + pte = pte_wrprotect(pte); + } + + /* If it's a shared mapping, mark it clean in the child. */ + if (src_vma->vm_flags & VM_SHARED) + pte = pte_mkclean(pte); + pte = pte_mkold(pte); + + if (!userfaultfd_wp(dst_vma)) + pte = pte_clear_uffd_wp(pte); + + set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); +} + /* * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page * is required to copy this pte. @@ -939,16 +962,16 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, pte_t *dst_pte, pte_t *src_pte, unsigned long addr, int *rss, struct folio **prealloc) { - struct mm_struct *src_mm = src_vma->vm_mm; - unsigned long vm_flags = src_vma->vm_flags; pte_t pte = ptep_get(src_pte); struct page *page; struct folio *folio; page = vm_normal_page(src_vma, addr, pte); - if (page) - folio = page_folio(page); - if (page && folio_test_anon(folio)) { + if (unlikely(!page)) + goto copy_pte; + + folio = page_folio(page); + if (folio_test_anon(folio)) { /* * If this page may have been pinned by the parent process, * copy the page immediately for the child so that we'll always @@ -963,34 +986,15 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, addr, rss, prealloc, page); } rss[MM_ANONPAGES]++; - } else if (page) { + VM_WARN_ON_FOLIO(PageAnonExclusive(page), folio); + } else { folio_get(folio); folio_dup_file_rmap_pte(folio, page); rss[mm_counter_file(page)]++; } - /* - * If it's a COW mapping, write protect it both - * in the parent and the child - */ - if (is_cow_mapping(vm_flags) && pte_write(pte)) { - ptep_set_wrprotect(src_mm, addr, src_pte); - pte = pte_wrprotect(pte); - } - VM_BUG_ON(page && folio_test_anon(folio) && PageAnonExclusive(page)); - - /* - * If it's a shared mapping, mark it clean in - * the child - */ - if (vm_flags & VM_SHARED) - pte = pte_mkclean(pte); - pte = pte_mkold(pte); - - if (!userfaultfd_wp(dst_vma)) - pte = pte_clear_uffd_wp(pte); - - set_pte_at(dst_vma->vm_mm, addr, dst_pte, pte); +copy_pte: + __copy_present_pte(dst_vma, src_vma, dst_pte, src_pte, pte, addr); return 0; }