From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755336AbdESNIc (ORCPT ); Fri, 19 May 2017 09:08:32 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:36350 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751190AbdESNIa (ORCPT ); Fri, 19 May 2017 09:08:30 -0400 Subject: Re: [PATCH v5 01/11] mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1 To: Zi Yan , n-horiguchi@ah.jp.nec.com, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20170420204752.79703-1-zi.yan@sent.com> <20170420204752.79703-2-zi.yan@sent.com> Cc: akpm@linux-foundation.org, minchan@kernel.org, vbabka@suse.cz, mgorman@techsingularity.net, mhocko@kernel.org, khandual@linux.vnet.ibm.com, zi.yan@cs.rutgers.edu, dnellans@nvidia.com, Dave Hansen , andi.kleen@intel.com From: Anshuman Khandual Date: Fri, 19 May 2017 18:37:22 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170420204752.79703-2-zi.yan@sent.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable x-cbid: 17051913-0012-0000-0000-000002357E93 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17051913-0013-0000-0000-0000074CD0CE Message-Id: <9497ce52-dd0d-0c99-2d0f-de980dfbe28e@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-05-19_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1705190082 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/21/2017 02:17 AM, Zi Yan wrote: > From: Naoya Horiguchi > > pmd_present() checks _PAGE_PSE along with _PAGE_PRESENT to avoid > false negative return when it races with thp spilt > (during which _PAGE_PRESENT is temporary cleared.) I don't think that > dropping _PAGE_PSE check in pmd_present() works well because it can > hurt optimization of tlb handling in thp split. > In the current kernel, bits 1-4 are not used in non-present format > since commit 00839ee3b299 ("x86/mm: Move swap offset/type up in PTE to > work around erratum"). So let's move _PAGE_SWP_SOFT_DIRTY to bit 1. > Bit 7 is used as reserved (always clear), so please don't use it for > other purpose. > > Signed-off-by: Naoya Horiguchi > Signed-off-by: Zi Yan +Dave Hansen +Andi Kleen Dave/Andi/Kiril, Does this change looks okay ? Its been on the list for some time now. Could you please have a look into this and lets us know your inputs/suggestions/comments ? Thank you. - Anshuman