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 46E5BC433FE for ; Fri, 18 Nov 2022 22:01:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229606AbiKRWBZ (ORCPT ); Fri, 18 Nov 2022 17:01:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230301AbiKRWBY (ORCPT ); Fri, 18 Nov 2022 17:01:24 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BA0591C0F for ; Fri, 18 Nov 2022 14:01:23 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B928AB8255C for ; Fri, 18 Nov 2022 22:01:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76664C433D6; Fri, 18 Nov 2022 22:01:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1668808880; bh=ESV2Hy7BHNZH/4xFLDENoKcfbhLwHfL9BtpbYNsbVkc=; h=Date:To:From:Subject:From; b=xD/PC4fPY5YjOfgbK4ERN4QWpkSThrXD8M3PZwOCcKseTljDBbJVb/UEEtjK6fvnz 4VwYbEVWBqb38aFaBr0aMWHQtfN6ZnbApjdqVL2+YJPjCoMnFPJ7AqBNqxFy5C11/u e2Llw8VRC1PLGgKrnYYMgoxbGlptRGfin3MedbQ0= Date: Fri, 18 Nov 2022 14:01:19 -0800 To: mm-commits@vger.kernel.org, zokeefe@google.com, willy@infradead.org, vbabka@suse.cz, torvalds@linux-foundation.org, songmuchun@bytedance.com, sidhartha.kumar@oracle.com, shy828301@gmail.com, peterx@redhat.com, naoya.horiguchi@linux.dev, mike.kravetz@oracle.com, linmiaohe@huawei.com, kirill@shutemov.name, jthoughton@google.com, jhubbard@nvidia.com, hannes@cmpxchg.org, david@redhat.com, almasrymina@google.com, hughd@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mmthprmap-clean-up-the-end-of-__split_huge_pmd_locked.patch added to mm-unstable branch Message-Id: <20221118220120.76664C433D6@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm,thp,rmap: clean up the end of __split_huge_pmd_locked() has been added to the -mm mm-unstable branch. Its filename is mmthprmap-clean-up-the-end-of-__split_huge_pmd_locked.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mmthprmap-clean-up-the-end-of-__split_huge_pmd_locked.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hugh Dickins Subject: mm,thp,rmap: clean up the end of __split_huge_pmd_locked() Date: Fri, 18 Nov 2022 01:16:20 -0800 (PST) It's hard to add a page_add_anon_rmap() into __split_huge_pmd_locked()'s HPAGE_PMD_NR set_pte_at() loop, without wincing at the "freeze" case's HPAGE_PMD_NR page_remove_rmap() loop below it. It's just a mistake to add rmaps in the "freeze" (insert migration entries prior to splitting huge page) case: the pmd_migration case already avoids doing that, so just follow its lead. page_add_ref() versus put_page() likewise. But why is one more put_page() needed in the "freeze" case? Because it's removing the pmd rmap, already removed when pmd_migration (and freeze and pmd_migration are mutually exclusive cases). Link: https://lkml.kernel.org/r/2f4afe60-40d2-706c-af21-914fbbbd164@google.com Signed-off-by: Hugh Dickins Cc: David Hildenbrand Cc: James Houghton Cc: Johannes Weiner Cc: John Hubbard Cc: "Kirill A . Shutemov" Cc: Linus Torvalds Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Mike Kravetz Cc: Mina Almasry Cc: Muchun Song Cc: Naoya Horiguchi Cc: Peter Xu Cc: Sidhartha Kumar Cc: Vlastimil Babka Cc: Yang Shi Cc: Zach O'Keefe Signed-off-by: Andrew Morton --- mm/huge_memory.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) --- a/mm/huge_memory.c~mmthprmap-clean-up-the-end-of-__split_huge_pmd_locked +++ a/mm/huge_memory.c @@ -2095,7 +2095,6 @@ static void __split_huge_pmd_locked(stru uffd_wp = pmd_uffd_wp(old_pmd); VM_BUG_ON_PAGE(!page_count(page), page); - page_ref_add(page, HPAGE_PMD_NR - 1); /* * Without "freeze", we'll simply split the PMD, propagating the @@ -2115,6 +2114,8 @@ static void __split_huge_pmd_locked(stru anon_exclusive = PageAnon(page) && PageAnonExclusive(page); if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) freeze = false; + if (!freeze) + page_ref_add(page, HPAGE_PMD_NR - 1); } /* @@ -2170,27 +2171,21 @@ static void __split_huge_pmd_locked(stru entry = pte_mksoft_dirty(entry); if (uffd_wp) entry = pte_mkuffd_wp(entry); + page_add_anon_rmap(page + i, vma, addr, false); } pte = pte_offset_map(&_pmd, addr); BUG_ON(!pte_none(*pte)); set_pte_at(mm, addr, pte, entry); - if (!pmd_migration) - page_add_anon_rmap(page + i, vma, addr, false); pte_unmap(pte); } if (!pmd_migration) page_remove_rmap(page, vma, true); + if (freeze) + put_page(page); smp_wmb(); /* make pte visible before pmd */ pmd_populate(mm, pmd, pgtable); - - if (freeze) { - for (i = 0; i < HPAGE_PMD_NR; i++) { - page_remove_rmap(page + i, vma, false); - put_page(page + i); - } - } } void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, _ Patches currently in -mm which might be from hughd@google.com are mmhugetlb-use-folio-fields-in-second-tail-page.patch mmhugetlb-use-folio-fields-in-second-tail-page-fix.patch mmthprmap-simplify-compound-page-mapcount-handling.patch mmthprmap-lock_compound_mapcounts-on-thp-mapcounts.patch mmthprmap-handle-the-normal-pagecompound-case-first.patch mmthprmap-subpages_mapcount-of-pte-mapped-subpages.patch mmthprmap-subpages_mapcount-compound_mapped-if-pmd-mapped.patch mmthprmap-clean-up-the-end-of-__split_huge_pmd_locked.patch