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[2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id bc7-20020a056402204700b005600b00a5f9si590624edb.524.2024.02.07.22.29.57 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Feb 2024 22:29:57 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-57523-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=Phoix+90; arc=pass (i=1 dkim=pass dkdomain=kernel.org); spf=pass (google.com: domain of linux-kernel+bounces-57523-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-57523-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id DEDBE1F222B7 for ; Thu, 8 Feb 2024 06:29:56 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8D9B267E7C; Thu, 8 Feb 2024 06:29:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Phoix+90" 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 A954067E67; Thu, 8 Feb 2024 06:29:46 +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=1707373786; cv=none; b=XwxXYush4ctiQsT/Mzb0zEldr1DYYNkcLd1W8cVfvCDlNWsJq4THKh+JtWaAmEQYNi7g/ZllPdqKLcJUdvvAJFQKRbvUF+2eiFbmPVDcCLBO09ycwzwoRy9eGdqbuScjpfBK9tPF01gQI3iTbhgCIgG24/lfvK7u7BwVsYIZEP4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707373786; c=relaxed/simple; bh=x4GCLa2xzNhu7jlHpC2LrDTqBpAccwVcIjWuUAdJzgc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nK6LUx6DTXCDoxGb8Yo0Q6e0fGFzSbyEgFGyloC7SZvX9phPLJ1GVp+GJIj1fg0SRnh0157QclJQpRM/SJv+cumnE3SgtkQJARYUJIY3RWP6KmytQkeOlruoPBwcODMjk4HCuDlVrMWa8XdszFjTyz4YKIUsABx3iP29CtCDP9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Phoix+90; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E21FC433F1; Thu, 8 Feb 2024 06:29:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707373786; bh=x4GCLa2xzNhu7jlHpC2LrDTqBpAccwVcIjWuUAdJzgc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Phoix+90khL4IEhQ6gpSoCEIa7eKrFuowZSgj42G9vOi8dSlpe1gQK0YyWgYKp+4r sPLY9+CUFb9aZvZlJVuQqwKhWZ+pa+B4zWmW6ij44vrjGh7IL5UzkD3sKKzoxbKYee QNwaU30tJ0UF6MuasMfjEGa+A4FY8V6otf3jfYDzeJPTIubtszyNvCkdBsoVBCTCKZ +W8z7CCvQhm6qI593PxMf1LOB8FDsoWbQ3LesFfp+jH1tSwZzvF1v7s5703XCDTQvu YYI3y/4CVWlLjbUJLn8zUCRy2xy0Roln1eAOTnw74B+sWgLw7OSbGWrqA5wjWVRClH ouB/3F6aDobjA== Date: Thu, 8 Feb 2024 08:29:21 +0200 From: Mike Rapoport To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, 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: Re: [PATCH v3 11/15] mm/memory: factor out copying the actual PTE in copy_present_pte() Message-ID: References: <20240129124649.189745-1-david@redhat.com> <20240129124649.189745-12-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240129124649.189745-12-david@redhat.com> On Mon, Jan 29, 2024 at 01:46:45PM +0100, David Hildenbrand wrote: > Let's prepare for further changes. > > Reviewed-by: Ryan Roberts > Signed-off-by: David Hildenbrand Reviewed-by: Mike Rapoport (IBM) > --- > mm/memory.c | 63 ++++++++++++++++++++++++++++------------------------- > 1 file changed, 33 insertions(+), 30 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index 8d14ba440929..a3bdb25f4c8d 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. > @@ -939,23 +962,23 @@ 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); > + folio_get(folio); > + 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 > * guarantee the pinned page won't be randomly replaced in the > * future. > */ > - folio_get(folio); > if (unlikely(folio_try_dup_anon_rmap_pte(folio, page, src_vma))) { > /* Page may be pinned, we have to copy. */ > folio_put(folio); > @@ -963,34 +986,14 @@ 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) { > - folio_get(folio); > + VM_WARN_ON_FOLIO(PageAnonExclusive(page), folio); > + } else { > folio_dup_file_rmap_pte(folio, page); > rss[mm_counter_file(folio)]++; > } > > - /* > - * 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; > } > > -- > 2.43.0 > > -- Sincerely yours, Mike.