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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 0E852C10F06 for ; Wed, 3 Apr 2019 08:49:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDF5D2147A for ; Wed, 3 Apr 2019 08:49:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554281358; bh=ffPOkgZdwfC3V2tcRbeNjPGHdLRiZ5ehp27X6fLG+3I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=KeYNr0j7blmXuh6MUWAXSRhLClqE/oRiZ/TFTA4YMW+6QX6MuYNsMaup5GfWJE0Fj 0wwMLjRJS7I0bLz2z4ccYlYwKkhBQKtphfRAbwQPHzDlQcDiO4CDVyymp5VWm3VnF3 ziWX0kza9RSa+qdKtq5I7jp3tfdDMRGp+dqWNUw0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729020AbfDCItR (ORCPT ); Wed, 3 Apr 2019 04:49:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:50864 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725822AbfDCItR (ORCPT ); Wed, 3 Apr 2019 04:49:17 -0400 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 BBDCCADA3; Wed, 3 Apr 2019 08:49:15 +0000 (UTC) Date: Wed, 3 Apr 2019 10:49:15 +0200 From: Michal Hocko To: David Hildenbrand Cc: Oscar Salvador , akpm@linux-foundation.org, dan.j.williams@intel.com, Jonathan.Cameron@huawei.com, anshuman.khandual@arm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 0/4] mm,memory_hotplug: allocate memmap from hotadded memory Message-ID: <20190403084915.GF15605@dhcp22.suse.cz> References: <20190329134243.GA30026@dhcp22.suse.cz> <20190401075936.bjt2qsrhw77rib77@d104.suse.de> <20190401115306.GF28293@dhcp22.suse.cz> <20190402082812.fefamf7qlzulb7t2@d104.suse.de> <20190402124845.GD28293@dhcp22.suse.cz> <20190403080113.adj2m3szhhnvzu56@d104.suse.de> <20190403081232.GB15605@dhcp22.suse.cz> <20190403083757.GC15605@dhcp22.suse.cz> <04a5b856-c8e0-937b-72bb-b9d17a12ccc7@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <04a5b856-c8e0-937b-72bb-b9d17a12ccc7@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 Wed 03-04-19 10:41:35, David Hildenbrand wrote: > On 03.04.19 10:37, Michal Hocko wrote: [...] > > That being said it should be the caller of the hotplug code to tell > > the vmemmap allocation strategy. For starter, I would only pack vmemmaps > > for "regular" kernel zone memory. Movable zones should be more careful. > > We can always re-evaluate later when there is a strong demand for huge > > pages on movable zones but this is not the case now because those pages > > are not really movable in practice. > > Remains the issue with potential different user trying to remove memory > it didn't add in some other granularity. We then really have to identify > and isolate that case. Can you give an example of a sensible usecase that would require this? -- Michal Hocko SUSE Labs