From mboxrd@z Thu Jan 1 00:00:00 1970 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 CB1DFC10F05 for ; Mon, 11 Dec 2023 16:18:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344438AbjLKQR7 (ORCPT ); Mon, 11 Dec 2023 11:17:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235023AbjLKQRo (ORCPT ); Mon, 11 Dec 2023 11:17:44 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 895E01BDB for ; Mon, 11 Dec 2023 08:17:22 -0800 (PST) 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 C5A1916F2; Mon, 11 Dec 2023 08:18:08 -0800 (PST) Received: from [10.57.73.30] (unknown [10.57.73.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DAF1B3F738; Mon, 11 Dec 2023 08:17:20 -0800 (PST) Message-ID: Date: Mon, 11 Dec 2023 16:17:19 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 03/39] mm/rmap: introduce and use hugetlb_add_file_rmap() Content-Language: en-GB To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Andrew Morton , "Matthew Wilcox (Oracle)" , Hugh Dickins , Yin Fengwei , Mike Kravetz , Muchun Song , Peter Xu References: <20231211155652.131054-1-david@redhat.com> <20231211155652.131054-4-david@redhat.com> From: Ryan Roberts In-Reply-To: <20231211155652.131054-4-david@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/12/2023 15:56, David Hildenbrand wrote: > hugetlb rmap handling differs quite a lot from "ordinary" rmap code. > For example, hugetlb currently only supports entire mappings, and treats > any mapping as mapped using a single "logical PTE". Let's move it out > of the way so we can overhaul our "ordinary" rmap. > implementation/interface. > > Right now we're using page_dup_file_rmap() in some cases where "ordinary" > rmap code would have used page_add_file_rmap(). So let's introduce and > use hugetlb_add_file_rmap() instead. We won't be adding a > "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be > doing the same: "dup" is just an optimization for "add". > > What remains is a single page_dup_file_rmap() call in fork() code. > > Reviewed-by: Yin Fengwei > Signed-off-by: David Hildenbrand Reviewed-by: Ryan Roberts > --- > include/linux/rmap.h | 7 +++++++ > mm/hugetlb.c | 6 +++--- > mm/migrate.c | 2 +- > 3 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/include/linux/rmap.h b/include/linux/rmap.h > index d85bd1d4de04..91178d1aa028 100644 > --- a/include/linux/rmap.h > +++ b/include/linux/rmap.h > @@ -213,6 +213,13 @@ void hugetlb_add_anon_rmap(struct folio *, struct vm_area_struct *, > void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *, > unsigned long address); > > +static inline void hugetlb_add_file_rmap(struct folio *folio) > +{ > + VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); > + > + atomic_inc(&folio->_entire_mapcount); > +} > + > static inline void hugetlb_remove_rmap(struct folio *folio) > { > atomic_dec(&folio->_entire_mapcount); > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index ef48ae673890..57e898187931 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -5408,7 +5408,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, > * sleep during the process. > */ > if (!folio_test_anon(pte_folio)) { > - page_dup_file_rmap(&pte_folio->page, true); > + hugetlb_add_file_rmap(pte_folio); > } else if (page_try_dup_anon_rmap(&pte_folio->page, > true, src_vma)) { > pte_t src_pte_old = entry; > @@ -6279,7 +6279,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, > if (anon_rmap) > hugetlb_add_new_anon_rmap(folio, vma, haddr); > else > - page_dup_file_rmap(&folio->page, true); > + hugetlb_add_file_rmap(folio); > new_pte = make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE) > && (vma->vm_flags & VM_SHARED))); > /* > @@ -6730,7 +6730,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, > goto out_release_unlock; > > if (folio_in_pagecache) > - page_dup_file_rmap(&folio->page, true); > + hugetlb_add_file_rmap(folio); > else > hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr); > > diff --git a/mm/migrate.c b/mm/migrate.c > index 4cb849fa0dd2..de9d94b99ab7 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -252,7 +252,7 @@ static bool remove_migration_pte(struct folio *folio, > hugetlb_add_anon_rmap(folio, vma, pvmw.address, > rmap_flags); > else > - page_dup_file_rmap(new, true); > + hugetlb_add_file_rmap(folio); > set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte, > psize); > } else