From nobody Wed Dec 24 16:01:43 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 9D02E137C41 for ; Thu, 25 Jan 2024 19:33:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706211228; cv=none; b=ly7ebO5ocCca3vT4yXyjg/kMcotBLla5ns15iLyc53tG7Bzd4rATlnx2J1LOX4zn6C2qVOVblwdyPTsLP4VyCZhzJlnXIzKF32wUT3e00w41sWk6RydxV/wtrI7i+t9usi1xPDnxBynnvwSjt5HAvwmcTdM2RwHkLQ2OFBaS/W8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706211228; c=relaxed/simple; bh=jFvxDvMCUuRleg4b4uXwFulr+9I6bJoh7tuuFWyWIOw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=B/taxRIUW9zeIjyloIZFfwTr9EZEGecszuSMCsuVph2feeuHmhxrzvmohrMUcXZ27RL/TRkyq73oCrn1kaAVp4fSj33adorHwdVgef0wDXiW09XEohgTmcuvB6Q5hES3cpWJfG7xREia78r1/v9Kcj9sYp/lsk14Umqfk/0PIrQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=O6G4nsp+; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="O6G4nsp+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706211225; 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=3s1Jv/6P5yjhblLF2udczJAUFVvnCKFeQLjRuwj24+c=; b=O6G4nsp+f9m150UyKJv1GWw9i0fAeRALLAHzYgNfqUWdPscvD7ksmuvG0Y5m+JOb6qBRhJ RdbrYU5sDTLYU1c5wHrpfqM13tadqo0JA14qJ3MArBYGb0hk98U56d+Ou0CvDk03bZvxpC hB47h+m91TiejNzhnzn1Wd3eFlu3qnc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-499-493L1nvTPrqpYIPc57u-fA-1; Thu, 25 Jan 2024 14:33:42 -0500 X-MC-Unique: 493L1nvTPrqpYIPc57u-fA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (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 34A868432A1; Thu, 25 Jan 2024 19:33:41 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.193.154]) by smtp.corp.redhat.com (Postfix) with ESMTP id 074EA492BC9; Thu, 25 Jan 2024 19:33:34 +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 v2 11/15] mm/memory: factor out copying the actual PTE in copy_present_pte() Date: Thu, 25 Jan 2024 20:32:23 +0100 Message-ID: <20240125193227.444072-12-david@redhat.com> In-Reply-To: <20240125193227.444072-1-david@redhat.com> References: <20240125193227.444072-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Content-Type: text/plain; charset="utf-8" Let's prepare for further changes. Reviewed-by: Ryan Roberts Signed-off-by: David Hildenbrand --- mm/memory.c | 63 ++++++++++++++++++++++++++++------------------------- 1 file changed, 33 insertions(+), 30 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 7e1f4849463aa..10fc14ff8e49b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -930,6 +930,29 @@ copy_present_page(struct vm_area_struct *dst_vma, stru= ct vm_area_struct *src_vma return 0; } =20 +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 =3D 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 =3D pte_wrprotect(pte); + } + + /* If it's a shared mapping, mark it clean in the child. */ + if (src_vma->vm_flags & VM_SHARED) + pte =3D pte_mkclean(pte); + pte =3D pte_mkold(pte); + + if (!userfaultfd_wp(dst_vma)) + pte =3D 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 p= age * is required to copy this pte. @@ -939,23 +962,23 @@ copy_present_pte(struct vm_area_struct *dst_vma, stru= ct 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 =3D src_vma->vm_mm; - unsigned long vm_flags =3D src_vma->vm_flags; pte_t pte =3D ptep_get(src_pte); struct page *page; struct folio *folio; =20 page =3D vm_normal_page(src_vma, addr, pte); - if (page) - folio =3D page_folio(page); - if (page && folio_test_anon(folio)) { + if (unlikely(!page)) + goto copy_pte; + + folio =3D 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, stru= ct 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(page)]++; } =20 - /* - * 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 =3D 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 =3D pte_mkclean(pte); - pte =3D pte_mkold(pte); - - if (!userfaultfd_wp(dst_vma)) - pte =3D 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; } =20 --=20 2.43.0