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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 36EEFC433E2 for ; Thu, 10 Sep 2020 11:12:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C921020C09 for ; Thu, 10 Sep 2020 11:12:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C921020C09 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 54EC56B007B; Thu, 10 Sep 2020 07:12:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5260B6B007D; Thu, 10 Sep 2020 07:12:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 463E66B007E; Thu, 10 Sep 2020 07:12:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0149.hostedemail.com [216.40.44.149]) by kanga.kvack.org (Postfix) with ESMTP id 31B296B007B for ; Thu, 10 Sep 2020 07:12:49 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DAAB08248047 for ; Thu, 10 Sep 2020 11:12:48 +0000 (UTC) X-FDA: 77246889216.14.table23_4802dd3270e5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin14.hostedemail.com (Postfix) with ESMTP id B1DFA18229818 for ; Thu, 10 Sep 2020 11:12:48 +0000 (UTC) X-HE-Tag: table23_4802dd3270e5 X-Filterd-Recvd-Size: 3171 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Thu, 10 Sep 2020 11:12:48 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D08DFABB2; Thu, 10 Sep 2020 11:13:02 +0000 (UTC) Date: Thu, 10 Sep 2020 13:12:46 +0200 From: Michal Hocko To: Laurent Dufour Cc: akpm@linux-foundation.org, David Hildenbrand , Oscar Salvador , rafael@kernel.org, nathanl@linux.ibm.com, cheloha@linux.ibm.com, stable@vger.kernel.org, Greg Kroah-Hartman , linux-mm@kvack.org, LKML Subject: Re: [PATCH] mm: don't rely on system state to detect hot-plug operations Message-ID: <20200910111246.GE28354@dhcp22.suse.cz> References: <5cbd92e1-c00a-4253-0119-c872bfa0f2bc@redhat.com> <20200908170835.85440-1-ldufour@linux.ibm.com> <20200909074011.GD7348@dhcp22.suse.cz> <9faac1ce-c02d-7dbc-f79a-4aaaa5a73d28@linux.ibm.com> <20200909090953.GE7348@dhcp22.suse.cz> <4cdb54be-1a92-4ba4-6fee-3b415f3468a9@linux.ibm.com> <20200909105914.GF7348@dhcp22.suse.cz> <74a62b00-235e-7deb-2814-f3b240fea25e@linux.ibm.com> <20200910072331.GB28354@dhcp22.suse.cz> <31cfdf35-618f-6f56-ef16-0d999682ad02@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <31cfdf35-618f-6f56-ef16-0d999682ad02@linux.ibm.com> X-Rspamd-Queue-Id: B1DFA18229818 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 10-09-20 09:51:39, Laurent Dufour wrote: > Le 10/09/2020 =E0 09:23, Michal Hocko a =E9crit=A0: > > On Wed 09-09-20 18:07:15, Laurent Dufour wrote: > > > Le 09/09/2020 =E0 12:59, Michal Hocko a =E9crit=A0: > > > > On Wed 09-09-20 11:21:58, Laurent Dufour wrote: > > [...] > > > > > For the point a, using the enum allows to know in > > > > > register_mem_sect_under_node() if the link operation is due to = a hotplug > > > > > operation or done at boot time. > > > >=20 > > > > Yes, but let me repeat. We have a mess here and different paths c= heck > > > > for the very same condition by different ways. We need to unify t= hose. > > >=20 > > > What are you suggesting to unify these checks (using a MP_* enum as > > > suggested by David, something else)? > >=20 > > We do have system_state check spread at different places. I would use > > this one and wrap it behind a helper. Or have I missed any reason why > > that wouldn't work for this case? >=20 > That would not work in that case because memory can be hot-added at the > SYSTEM_SCHEDULING system state and the regular memory is also registere= d at > that system state too. So system state is not enough to discriminate be= tween > the both. If that is really the case all other places need a fix as well. Btw. could you be more specific about memory hotplug during early boot? How that happens? I am only aware of https://lkml.kernel.org/r/2020081811= 0046.6664-1-osalvador@suse.de and that doesn't happen as early as SYSTEM_SCHEDULING. --=20 Michal Hocko SUSE Labs