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 X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6DACC43142 for ; Fri, 22 Jun 2018 08:00:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9EBAE23E88 for ; Fri, 22 Jun 2018 08:00:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9EBAE23E88 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751423AbeFVIAA (ORCPT ); Fri, 22 Jun 2018 04:00:00 -0400 Received: from mga14.intel.com ([192.55.52.115]:32271 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751119AbeFVH76 (ORCPT ); Fri, 22 Jun 2018 03:59:58 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Jun 2018 00:59:58 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,255,1526367600"; d="scan'208";a="59316311" Received: from black.fi.intel.com ([10.237.72.28]) by FMSMGA003.fm.intel.com with ESMTP; 22 Jun 2018 00:59:56 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 4DDBD143; Fri, 22 Jun 2018 10:59:58 +0300 (EEST) Date: Fri, 22 Jun 2018 10:59:58 +0300 From: "Kirill A. Shutemov" To: yang.shi@linux.alibaba.com Cc: hughd@google.com, vbabka@suse.cz, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [v2 PATCH 1/2] mm: thp: register mm for khugepaged when merging vma for shmem Message-ID: <20180622075958.mzagr2ayufiuokea@black.fi.intel.com> References: <1529622949-75504-1-git-send-email-yang.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1529622949-75504-1-git-send-email-yang.shi@linux.alibaba.com> User-Agent: NeoMutt/20170714-126-deb55f (1.8.3) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 21, 2018 at 11:15:48PM +0000, yang.shi@linux.alibaba.com wrote: > When merging anonymous page vma, if the size of vma can fit in at least > one hugepage, the mm will be registered for khugepaged for collapsing > THP in the future. > > But, it skips shmem vma. Doing so for shmem too, but not file-private > mapping, when merging vma in order to increase the odd to collapse > hugepage by khugepaged. > > Signed-off-by: Yang Shi > Cc: Hugh Dickins > Cc: Kirill A. Shutemov > Cc: Vlastimil Babka > --- > v1 --> 2: > * Exclude file-private mapping per Kirill's comment > > mm/khugepaged.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index d7b2a4b..9b0ec30 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -440,8 +440,12 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma, > * page fault if needed. > */ > return 0; > - if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED)) > - /* khugepaged not yet working on file or special mappings */ > + if ((vma->vm_ops && (!shmem_file(vma->vm_file) || vma->anon_vma)) || > + (vm_flags & VM_NO_KHUGEPAGED)) > + /* > + * khugepaged not yet working on non-shmem file or special > + * mappings. And, file-private shmem THP is not supported. > + */ > return 0; My point was that vma->anon_vma check above this one should not prevent collapse for shmem. Looking into this more, I think we should just replace all these checks with hugepage_vma_check() call. -- Kirill A. Shutemov