From nobody Sun Feb 8 21:47:12 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03D74EB64DC for ; Mon, 3 Jul 2023 13:53:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbjGCNx4 (ORCPT ); Mon, 3 Jul 2023 09:53:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230252AbjGCNxw (ORCPT ); Mon, 3 Jul 2023 09:53:52 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0716010C8 for ; Mon, 3 Jul 2023 06:53:45 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 71661C14; Mon, 3 Jul 2023 06:54:27 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EDAF83F73F; Mon, 3 Jul 2023 06:53:42 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , Matthew Wilcox , "Kirill A. Shutemov" , Yin Fengwei , David Hildenbrand , Yu Zhao , Catalin Marinas , Will Deacon , Anshuman Khandual , Yang Shi Cc: Ryan Roberts , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 1/5] mm: Non-pmd-mappable, large folios for folio_add_new_anon_rmap() Date: Mon, 3 Jul 2023 14:53:26 +0100 Message-Id: <20230703135330.1865927-2-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230703135330.1865927-1-ryan.roberts@arm.com> References: <20230703135330.1865927-1-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In preparation for FLEXIBLE_THP support, improve folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be passed to it. In this case, all contained pages are accounted using the "small" pages scheme. Signed-off-by: Ryan Roberts Reviewed-by: Yin, Fengwei Reviewed-by: Yu Zhao --- mm/rmap.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 1d8369549424..82ef5ba363d1 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1278,31 +1278,43 @@ void page_add_anon_rmap(struct page *page, struct v= m_area_struct *vma, * This means the inc-and-test can be bypassed. * The folio does not have to be locked. * - * If the folio is large, it is accounted as a THP. As the folio + * If the folio is pmd-mappable, it is accounted as a THP. As the folio * is new, it's assumed to be mapped exclusively by a single process. */ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *v= ma, unsigned long address) { - int nr; + int nr =3D folio_nr_pages(folio); + int i; + struct page *page; =20 - VM_BUG_ON_VMA(address < vma->vm_start || address >=3D vma->vm_end, vma); + VM_BUG_ON_VMA(address < vma->vm_start || + address + (nr << PAGE_SHIFT) > vma->vm_end, vma); __folio_set_swapbacked(folio); =20 - if (likely(!folio_test_pmd_mappable(folio))) { + if (!folio_test_large(folio)) { /* increment count (starts at -1) */ atomic_set(&folio->_mapcount, 0); - nr =3D 1; + __page_set_anon_rmap(folio, &folio->page, vma, address, 1); + } else if (!folio_test_pmd_mappable(folio)) { + /* increment count (starts at 0) */ + atomic_set(&folio->_nr_pages_mapped, nr); + + page =3D &folio->page; + for (i =3D 0; i < nr; i++, page++, address +=3D PAGE_SIZE) { + /* increment count (starts at -1) */ + atomic_set(&page->_mapcount, 0); + __page_set_anon_rmap(folio, page, vma, address, 1); + } } else { /* increment count (starts at -1) */ atomic_set(&folio->_entire_mapcount, 0); atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED); - nr =3D folio_nr_pages(folio); __lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr); + __page_set_anon_rmap(folio, &folio->page, vma, address, 1); } =20 __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr); - __page_set_anon_rmap(folio, &folio->page, vma, address, 1); } =20 /** --=20 2.25.1