From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one.patch added to -mm tree Date: Thu, 08 Feb 2018 14:39:56 -0800 Message-ID: <5a7cd1bc.yFSKRcMrDmYkxijb%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58364 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079AbeBHWj5 (ORCPT ); Thu, 8 Feb 2018 17:39:57 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: yang.shi@linux.alibaba.com, akpm@linux-foundation.org, gavin.dg@linux.alibaba.com, kirill.shutemov@linux.intel.com, mm-commits@vger.kernel.org The patch titled Subject: mm: thp: fix potential clearing to referenced flag in page_idle_clear_pte_refs_one() has been added to the -mm tree. Its filename is mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one.patch 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/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Yang Shi Subject: mm: thp: fix potential clearing to referenced flag in page_idle_clear_pte_refs_one() For PTE-mapped THP, the compound THP has not been split to normal 4K pages yet, the whole THP is considered referenced if any one of sub page is referenced. When walking PTE-mapped THP by pvmw, all relevant PTEs will be checked to retrieve referenced bit. But, the current code just returns the result of the last PTE. If the last PTE has not referenced, the referenced flag will be cleared. So, here just break pvmw walk once referenced PTE is found if the page is a part of THP. Link: http://lkml.kernel.org/r/1517875596-76350-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi Reported-by: Gang Deng Reviewed-by: Andrew Morton Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton --- mm/page_idle.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN mm/page_idle.c~mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one mm/page_idle.c --- a/mm/page_idle.c~mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one +++ a/mm/page_idle.c @@ -67,6 +67,14 @@ static bool page_idle_clear_pte_refs_one if (pvmw.pte) { referenced = ptep_clear_young_notify(vma, addr, pvmw.pte); + /* + * For PTE-mapped THP, one sub page is referenced, + * the whole THP is referenced. + */ + if (referenced && PageTransCompound(pvmw.page)) { + page_vma_mapped_walk_done(&pvmw); + break; + } } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { referenced = pmdp_clear_young_notify(vma, addr, pvmw.pmd); _ Patches currently in -mm which might be from yang.shi@linux.alibaba.com are mm-thp-fix-potential-clearing-to-referenced-flag-in-page_idle_clear_pte_refs_one.patch