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=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 B288CC433F5 for ; Wed, 5 Sep 2018 06:57:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65CC22075E for ; Wed, 5 Sep 2018 06:57:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65CC22075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1727685AbeIEL0f (ORCPT ); Wed, 5 Sep 2018 07:26:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:38800 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726272AbeIEL0e (ORCPT ); Wed, 5 Sep 2018 07:26:34 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 5691BADE2; Wed, 5 Sep 2018 06:57:49 +0000 (UTC) Date: Wed, 5 Sep 2018 08:57:46 +0200 From: Michal Hocko To: Jerome Glisse Cc: Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A . Shutemov" , Vlastimil Babka , Naoya Horiguchi , Davidlohr Bueso , Andrew Morton , stable@vger.kernel.org, linux-rdma@vger.kernel.org, Matan Barak , Leon Romanovsky , Dimitri Sivanich Subject: Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages Message-ID: <20180905065746.GY14951@dhcp22.suse.cz> References: <20180829183906.GF10223@dhcp22.suse.cz> <20180829211106.GC3784@redhat.com> <20180830105616.GD2656@dhcp22.suse.cz> <20180830140825.GA3529@redhat.com> <20180830161800.GJ2656@dhcp22.suse.cz> <20180830165751.GD3529@redhat.com> <20180830183944.GE3529@redhat.com> <20180903055654.GA14951@dhcp22.suse.cz> <20180904140035.GA3526@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180904140035.GA3526@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 04-09-18 10:00:36, Jerome Glisse wrote: > On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: [...] > > And THP migration is still a problem with 4.4 AFAICS. All other cases > > simply split the huge page but THP migration keeps it in one piece and > > as such it is theoretically broken as you have explained. So I would > > stick with what I posted with some more clarifications in the changelog > > if you think it is appropriate (suggestions welcome). > > Reading code there is no THP migration in 4.4 only huge tlb migration. Meh, you are right. For some reason I misread unmap_and_move_huge_page to be also for THP. Sorry for the conusion. My fault! Then it would be indeed safer to use your backport. -- Michal Hocko SUSE Labs