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=-7.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 384F7C10F0E for ; Thu, 18 Apr 2019 20:30:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0502C217D7 for ; Thu, 18 Apr 2019 20:30:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="SwnFKNon" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390118AbfDRUac (ORCPT ); Thu, 18 Apr 2019 16:30:32 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:17090 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731565AbfDRUab (ORCPT ); Thu, 18 Apr 2019 16:30:31 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 18 Apr 2019 13:30:36 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 18 Apr 2019 13:30:31 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 18 Apr 2019 13:30:31 -0700 Received: from [10.2.163.72] (172.20.13.39) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 18 Apr 2019 20:30:29 +0000 From: Zi Yan To: Yang Shi CC: , , , , , , , Subject: Re: [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore Date: Thu, 18 Apr 2019 16:30:27 -0400 X-Mailer: MailMate (1.12.4r5622) Message-ID: In-Reply-To: <1555618624-23957-1-git-send-email-yang.shi@linux.alibaba.com> References: <1555618624-23957-1-git-send-email-yang.shi@linux.alibaba.com> MIME-Version: 1.0 X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL103.nvidia.com (172.20.187.11) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: text/plain; format=flowed DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1555619436; bh=T3JD0sgSOXk1vRSr1uVe9SorhMd4n+SS+HWTi6IFNCc=; h=X-PGP-Universal:From:To:CC:Subject:Date:X-Mailer:Message-ID: In-Reply-To:References:MIME-Version:X-Originating-IP: X-ClientProxiedBy:Content-Type; b=SwnFKNonXOE1zQVJWCyAkBVjCLR/gdo0c98WcA4gmTZefaRGQCthtZhxg/jleQzpb 9ey3mfNA2l5uwtSrjts4734cmnAQzrvuHJkA0/uVgRhdrUSqaEEH5iSCLqsgZ+z1mf eeg11NLcYkIb/mqsgxPlqRYvLKPIDYGdSbrtnlZUeJ4SkRHOQlXkM81nzq/VmKWoBq F+ZustVToSp/Ww2x7qBHKYszHEDGptzDItgUiSNegC2a4t8wVt2Udzszw5zk7EYoRl T2VVXWCXJVBoGCwEAjqmLJrf4butHZI6agSmOQ0mGBaG9CzXgI07vrYyRDygRIjFSL N81lBCiahYjRw== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18 Apr 2019, at 16:17, Yang Shi wrote: > When demonstrating FOLL_SPLIT in transhuge document, migration is used > as an example. But, since commit 94723aafb9e7 ("mm: unclutter THP > migration"), the way of THP migration is totally changed. FOLL_SPLIT > is > not used by migration anymore due to the change. > > Remove the obsolete example to avoid confusion. > > Cc: Michal Hocko > Cc: Kirill A. Shutemov > Cc: Zi Yan > Cc: Mike Rapoport > Signed-off-by: Yang Shi > --- > Documentation/vm/transhuge.rst | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/Documentation/vm/transhuge.rst > b/Documentation/vm/transhuge.rst > index a8cf680..8df3806 100644 > --- a/Documentation/vm/transhuge.rst > +++ b/Documentation/vm/transhuge.rst > @@ -55,13 +55,7 @@ prevent page from being split by anyone. > In case you can't handle compound pages if they're returned by > follow_page, the FOLL_SPLIT bit can be specified as parameter to > follow_page, so that it will split the hugepages before returning > -them. Migration for example passes FOLL_SPLIT as parameter to > -follow_page because it's not hugepage aware and in fact it can't work > -at all on hugetlbfs (but it instead works fine on transparent > -hugepages thanks to FOLL_SPLIT). migration simply can't deal with > -hugepages being returned (as it's not only checking the pfn of the > -page and pinning it during the copy but it pretends to migrate the > -memory in regular page sizes and with regular pte/pmd mappings). > +them. > > Graceful fallback > ================= > -- > 1.8.3.1 Thanks for updating the document. Reviewed-by: Zi Yan -- Best Regards, Yan Zi