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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 C0321C433ED for ; Tue, 13 Apr 2021 09:49:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A570C613BA for ; Tue, 13 Apr 2021 09:49:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240265AbhDMJty (ORCPT ); Tue, 13 Apr 2021 05:49:54 -0400 Received: from outbound-smtp33.blacknight.com ([81.17.249.66]:45231 "EHLO outbound-smtp33.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241211AbhDMJto (ORCPT ); Tue, 13 Apr 2021 05:49:44 -0400 Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp33.blacknight.com (Postfix) with ESMTPS id CD6FABABFE for ; Tue, 13 Apr 2021 10:49:23 +0100 (IST) Received: (qmail 31546 invoked from network); 13 Apr 2021 09:49:23 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.22.4]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 13 Apr 2021 09:49:23 -0000 Date: Tue, 13 Apr 2021 10:49:20 +0100 From: Mel Gorman To: Vlastimil Babka Cc: Andrew Morton , Oscar Salvador , "Michael S. Tsirkin" , Alexander Duyck , Minchan Kim , Michal Hocko , David Hildenbrand , Linux-MM , LKML Subject: Re: [PATCH v2 resend] mm/memory_hotplug: Make unpopulated zones PCP structures unreachable during hot remove Message-ID: <20210413094920.GC3697@techsingularity.net> References: <20210412120842.GY3697@techsingularity.net> <20210412140852.GZ3697@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 13, 2021 at 11:36:08AM +0200, Vlastimil Babka wrote: > On 4/12/21 4:08 PM, Mel Gorman wrote: > > On Mon, Apr 12, 2021 at 02:40:18PM +0200, Vlastimil Babka wrote: > >> On 4/12/21 2:08 PM, Mel Gorman wrote: > > > > the pageset structures in place would be much more straight-forward > > assuming the structures were not allocated in the zone that is being > > hot-removed. > > I would expect this is not possible, at least for ZONE_MOVABLE, as the percpu > allocations should be GFP_KERNEL. True. > And it's not realistic to expect offlining to > succeed at all without using ZONE_MOVABLE. > > AFAIK even Oscar's work on using the node to self-contain its own structures is > only applicable to struct pages, not percpu allocations? That I don't know as I didn't check although in general, it would be somewhat unfortunate if per-cpu structures were remote. It wouldn't be critical given that they'll be in cache assuming the per-cpu structures are not straddling cache lines. -- Mel Gorman SUSE Labs