Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756101AbcKJWwD convert rfc822-to-8bit (ORCPT ); Thu, 10 Nov 2016 17:52:03 -0500 Received: from TYO202.gate.nec.co.jp ([210.143.35.52]:46157 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756077AbcKJWwA (ORCPT ); Thu, 10 Nov 2016 17:52:00 -0500 From: Naoya Horiguchi To: Anshuman Khandual CC: "linux-mm@kvack.org" , "Kirill A. Shutemov" , Hugh Dickins , "Andrew Morton" , Dave Hansen , Andrea Arcangeli , Mel Gorman , Michal Hocko , "Vlastimil Babka" , Pavel Emelyanov , Zi Yan , Balbir Singh , "linux-kernel@vger.kernel.org" , "Naoya Horiguchi" Subject: Re: [PATCH v2 05/12] mm: thp: add core routines for thp/pmd migration Thread-Topic: [PATCH v2 05/12] mm: thp: add core routines for thp/pmd migration Thread-Index: AQHSOU9Q7WDKwpLw/E++HKi9rnTMz6DRT36AgAAUyYA= Date: Thu, 10 Nov 2016 09:43:28 +0000 Message-ID: <20161110094327.GE9173@hori1.linux.bs1.fc.nec.co.jp> References: <1478561517-4317-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1478561517-4317-6-git-send-email-n-horiguchi@ah.jp.nec.com> <58242FCF.50602@linux.vnet.ibm.com> In-Reply-To: <58242FCF.50602@linux.vnet.ibm.com> Accept-Language: en-US, ja-JP Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.28] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1707 Lines: 41 On Thu, Nov 10, 2016 at 01:59:03PM +0530, Anshuman Khandual wrote: > On 11/08/2016 05:01 AM, Naoya Horiguchi wrote: > > This patch prepares thp migration's core code. These code will be open when > > unmap_and_move() stops unconditionally splitting thp and get_new_page() starts > > to allocate destination thps. > > > > Snip > > > Signed-off-by: Naoya Horiguchi > > --- > > ChangeLog v1 -> v2: > > - support pte-mapped thp, doubly-mapped thp > > --- > > arch/x86/include/asm/pgtable_64.h | 2 + > > include/linux/swapops.h | 61 +++++++++++++++ > > mm/huge_memory.c | 154 ++++++++++++++++++++++++++++++++++++++ > > mm/migrate.c | 44 ++++++++++- > > mm/pgtable-generic.c | 3 +- > > 5 files changed, 262 insertions(+), 2 deletions(-) > > > > diff --git v4.9-rc2-mmotm-2016-10-27-18-27/mm/pgtable-generic.c v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/pgtable-generic.c > > index 71c5f91..6012343 100644 > > --- v4.9-rc2-mmotm-2016-10-27-18-27/mm/pgtable-generic.c > > +++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/pgtable-generic.c > > @@ -118,7 +118,8 @@ pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address, > > { > > pmd_t pmd; > > VM_BUG_ON(address & ~HPAGE_PMD_MASK); > > - VM_BUG_ON(!pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp)); > > + VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) && > > + !pmd_devmap(*pmdp)) > > Its a valid VM_BUG_ON check but is it related to THP migration or > just a regular fix up ? Without this change, this VM_BUG_ON always triggers when migration happens on normal thp and it succeeds, so I included it here. - Naoya Horiguchi