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=-3.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED, 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 4B7D4C4321D for ; Wed, 22 Aug 2018 21:13:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2D88208E3 for ; Wed, 22 Aug 2018 21:13:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="juOGvQGZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2D88208E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shutemov.name 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 S1728003AbeHWAk0 (ORCPT ); Wed, 22 Aug 2018 20:40:26 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:47006 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727250AbeHWAkZ (ORCPT ); Wed, 22 Aug 2018 20:40:25 -0400 Received: by mail-pg1-f193.google.com with SMTP id b129-v6so1467566pga.13 for ; Wed, 22 Aug 2018 14:13:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ZeZtC1OZjSMCa2q8CctA0YI/urjnWDXPoeqECLJOF+I=; b=juOGvQGZWZh6SN686zjsZ58qM1zDqJDwDu8iqnwVpfSMd+k7263NsLthDE1rfmn0eo 08B2vkhqPXYjxOahbja7B0PPBmFGuy+5dLMka9eMnBvOzJj0s2aS6zL3uHkEKTv8RPZf GxQmgD8EcCGY4j8N0gYHb0Tb2pSTZi5+tqj04eEP93Yyee5qf+XxX2Y5/aXE/KA/U4R+ /QMMhG9nYPvR0lStHobRoOE8CSwSAWkgyjpf5YoPhDr1p123L/gA6Vpa6ED7O3s9qX58 5kYC/H1e7v4hcAcB9RXqnOcBgpT3uoSnRqLgQBGriJShvhk1OxdIPFR9Er6esrJwzRa1 PhZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ZeZtC1OZjSMCa2q8CctA0YI/urjnWDXPoeqECLJOF+I=; b=am2Amb+2xQSR6r1k0csunvWussLypTBUKi0GGgi5wmqTO0zoKizcTVNOBJlmTuZI5+ CJXxPYhFOTVZt1SRK/+IZuhR1HhcKb7kh8j9ppAlQwYddjoBLUkMVUPZtkPaSQQsbAaI aBHNEASEPryfZ4mBtN0Ba84UEo48pLTX7Vwpr5/l4yVopME8f4DT59YaQgRMviz7tOP/ zR42sq0SQSHk77TjiUAsH2VmgIEAOLMvvGEqIEtX5sFufCDN/0dsbRwZ2Xj7yIpZSwS3 JP+mGGrjtz/35E+OjsHbMA5yAtpflKWOrw4Egc73ddVqhxdgfHJSuQYFafzy0cSJb51i pG2w== X-Gm-Message-State: AOUpUlEy6ordLfD+rBQmVx/xNpM20szwv4LGzT8e82o0TTfxOdAfVnXq 8oJGHYwAWUSxceXvU6OieoCvoQ== X-Google-Smtp-Source: AA+uWPyOd2G9pkkQ5qrPv+75bB37EtxGFWsypSSKjxyQ3UP44TCNfNKRgFkX4ObPKwUTbzo6PU7mRg== X-Received: by 2002:a63:5143:: with SMTP id r3-v6mr53732383pgl.11.1534972434535; Wed, 22 Aug 2018 14:13:54 -0700 (PDT) Received: from kshutemo-mobl1.localdomain ([134.134.139.83]) by smtp.gmail.com with ESMTPSA id g66-v6sm4537522pfk.39.2018.08.22.14.13.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Aug 2018 14:13:53 -0700 (PDT) Received: by kshutemo-mobl1.localdomain (Postfix, from userid 1000) id 3CE1F3000BD; Thu, 23 Aug 2018 00:05:07 +0300 (+03) Date: Thu, 23 Aug 2018 00:05:07 +0300 From: "Kirill A. Shutemov" To: Mike Kravetz Cc: kbuild test robot , kbuild-all@01.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A . Shutemov" , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Vlastimil Babka , Naoya Horiguchi , Davidlohr Bueso , Michal Hocko , Andrew Morton , stable@vger.kernel.org Subject: Re: [PATCH v3 1/2] mm: migration: fix migration of huge PMD shared pages Message-ID: <20180822210507.lvb26bghqmt6c5fw@kshutemo-mobl1> References: <20180821205902.21223-2-mike.kravetz@oracle.com> <201808220831.eM0je51n%fengguang.wu@intel.com> <975b740d-26a6-eb3f-c8ca-1a9995d0d343@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <975b740d-26a6-eb3f-c8ca-1a9995d0d343@oracle.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 21, 2018 at 06:10:42PM -0700, Mike Kravetz wrote: > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 3103099f64fd..f085019a4724 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4555,6 +4555,9 @@ static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr) > > /* > * check on proper vm_flags and page table alignment > + * > + * Note that this is the same check used in huge_pmd_sharing_possible. > + * If you change one, consider changing both. Should we have helper to isolate the check in one place? > */ > if (vma->vm_flags & VM_MAYSHARE && > vma->vm_start <= base && end <= vma->vm_end) > @@ -4562,6 +4565,43 @@ static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr) > return false; > } > > +/* > + * Determine if start,end range within vma could be mapped by shared pmd. > + * If yes, adjust start and end to cover range associated with possible > + * shared pmd mappings. > + */ > +bool huge_pmd_sharing_possible(struct vm_area_struct *vma, > + unsigned long *start, unsigned long *end) > +{ > + unsigned long check_addr = *start; > + bool ret = false; > + > + if (!(vma->vm_flags & VM_MAYSHARE)) > + return ret; Do we ever use return value? I don't see it. And in this case function name is not really work... > + for (check_addr = *start; check_addr < *end; check_addr += PUD_SIZE) { > + unsigned long a_start = check_addr & PUD_MASK; > + unsigned long a_end = a_start + PUD_SIZE; > + > + /* > + * If sharing is possible, adjust start/end if necessary. > + * > + * Note that this is the same check used in vma_shareable. If > + * you change one, consider changing both. > + */ > + if (vma->vm_start <= a_start && a_end <= vma->vm_end) { > + if (a_start < *start) > + *start = a_start; > + if (a_end > *end) > + *end = a_end; > + > + ret = true; > + } > + } > + > + return ret; > +} > + -- Kirill A. Shutemov