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 2D39DC0044C for ; Mon, 5 Nov 2018 17:10:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E512B20827 for ; Mon, 5 Nov 2018 17:10:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E512B20827 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 S1729927AbeKFCao (ORCPT ); Mon, 5 Nov 2018 21:30:44 -0500 Received: from mx2.suse.de ([195.135.220.15]:59486 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729733AbeKFCao (ORCPT ); Mon, 5 Nov 2018 21:30:44 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id D9BD8B0B3; Mon, 5 Nov 2018 17:10:04 +0000 (UTC) Date: Mon, 5 Nov 2018 18:10:02 +0100 From: Michal Hocko To: Baoquan He Cc: Andrew Morton , linux-mm@kvack.org, LKML , Stable tree Subject: Re: [PATCH] mm, memory_hotplug: teach has_unmovable_pages about of LRU migrateable pages Message-ID: <20181105171002.GO4361@dhcp22.suse.cz> References: <20181101091055.GA15166@MiWiFi-R3L-srv> <20181102155528.20358-1-mhocko@kernel.org> <20181105002009.GF27491@MiWiFi-R3L-srv> <20181105091407.GB4361@dhcp22.suse.cz> <20181105092851.GD4361@dhcp22.suse.cz> <20181105102520.GB22011@MiWiFi-R3L-srv> <20181105123837.GH4361@dhcp22.suse.cz> <20181105142308.GJ27491@MiWiFi-R3L-srv> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181105142308.GJ27491@MiWiFi-R3L-srv> 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 Mon 05-11-18 22:23:08, Baoquan He wrote: > On 11/05/18 at 01:38pm, Michal Hocko wrote: > > On Mon 05-11-18 18:25:20, Baoquan He wrote: > > > Hi Michal, > > > > > > On 11/05/18 at 10:28am, Michal Hocko wrote: > > > > > > > > Or something like this. Ugly as hell, no question about that. I also > > > > have to think about this some more to convince myself this will not > > > > result in an endless loop under some situations. > > > > > > It failed. Paste the log and patch diff here, please help check if I made > > > any mistake on manual code change. The log is at bottom. > > > > The retry patch is obviously still racy, it just makes the race window > > slightly smaller and I hoped it would catch most of those races but this > > is obviously not the case. > > > > I was thinking about your MIGRATE_MOVABLE check some more and I still do > > not like it much, we just change migrate type at many places and I have > > hard time to actually see this is always safe wrt. to what we need here. > > > > We should be able to restore the zone type check though. The > > primary problem fixed by 15c30bc09085 ("mm, memory_hotplug: make > > has_unmovable_pages more robust") was that early allocations made it to > > the zone_movable range. If we add the check _after_ the PageReserved() > > check then we should be able to rule all bootmem allocation out. > > > > So what about the following (on top of the previous patch which makes > > sense on its own I believe). > > Yes, I think this looks very reasonable and should be robust. > > Have tested it, hot removing 4 hotpluggable nodes continusously > succeeds, and then hot adding them back, still works well. > > So please feel free to add my Tested-by or Acked-by. > > Tested-by: Baoquan He > or > Acked-by: Baoquan He Thanks for retesting! Does this apply to both patches? -- Michal Hocko SUSE Labs