From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:49108 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725866AbfGaIDN (ORCPT ); Wed, 31 Jul 2019 04:03:13 -0400 Date: Wed, 31 Jul 2019 10:03:09 +0200 From: Michal Hocko Subject: Re: [PATCH v2 0/5] mm: Enable CONFIG_NODES_SPAN_OTHER_NODES by default for NUMA Message-ID: <20190731080309.GZ9330@dhcp22.suse.cz> References: <1562887528-5896-1-git-send-email-Hoan@os.amperecomputing.com> <20190712070247.GM29483@dhcp22.suse.cz> <586ae736-a429-cf94-1520-1a94ffadad88@os.amperecomputing.com> <20190712121223.GR29483@dhcp22.suse.cz> <20190712143730.au3662g4ua2tjudu@willie-the-truck> <20190712150007.GU29483@dhcp22.suse.cz> <730368c5-1711-89ae-e3ef-65418b17ddc9@os.amperecomputing.com> <20190730081415.GN9330@dhcp22.suse.cz> <20190731062420.GC21422@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190731062420.GC21422@rapoport-lnx> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Mike Rapoport Cc: Hoan Tran OS , Will Deacon , Catalin Marinas , Heiko Carstens , "open list:MEMORY MANAGEMENT" , Paul Mackerras , "H . Peter Anvin" , "sparclinux@vger.kernel.org" , Alexander Duyck , "linux-s390@vger.kernel.org" , Michael Ellerman , "x86@kernel.org" , Christian Borntraeger , Ingo Molnar , Vlastimil Babka , Benjamin Herrenschmidt , Open Source Submission , Pavel Tatashin , Vasily Gorbik , Will Deacon , Borislav Petkov , Thomas Gleixner , "linux-arm-kernel@lists.infradead.org" , Oscar Salvador , "linux-kernel@vger.kernel.org" , Andrew Morton , "linuxppc-dev@lists.ozlabs.org" , "David S . Miller" , "willy@infradead.org" On Wed 31-07-19 09:24:21, Mike Rapoport wrote: > [ sorry for a late reply too, somehow I missed this thread before ] > > On Tue, Jul 30, 2019 at 10:14:15AM +0200, Michal Hocko wrote: > > [Sorry for a late reply] > > > > On Mon 15-07-19 17:55:07, Hoan Tran OS wrote: > > > Hi, > > > > > > On 7/12/19 10:00 PM, Michal Hocko wrote: > > [...] > > > > Hmm, I thought this was selectable. But I am obviously wrong here. > > > > Looking more closely, it seems that this is indeed only about > > > > __early_pfn_to_nid and as such not something that should add a config > > > > symbol. This should have been called out in the changelog though. > > > > > > Yes, do you have any other comments about my patch? > > > > Not really. Just make sure to explicitly state that > > CONFIG_NODES_SPAN_OTHER_NODES is only about __early_pfn_to_nid and that > > doesn't really deserve it's own config and can be pulled under NUMA. > > > > > > Also while at it, does HAVE_MEMBLOCK_NODE_MAP fall into a similar > > > > bucket? Do we have any NUMA architecture that doesn't enable it? > > > > > > HAVE_MEMBLOCK_NODE_MAP makes huge difference in node/zone initialization > sequence so it's not only about a singe function. The question is whether we want to have this a config option or enable it unconditionally for each NUMA system. > > > As I checked with arch Kconfig files, there are 2 architectures, riscv > > > and microblaze, do not support NUMA but enable this config. > > My take would be that riscv will support NUMA some day. > > > > And 1 architecture, alpha, supports NUMA but does not enable this config. > > alpha's NUMA support is BROKEN for more than a decade now, I doubt it'll > ever get fixed. I can see Al has marked it BROKEN in 2005. Maybe time to rip it out? Although it doesn't seem to be a lot of code in arch/alpha at first glance so maybe not worth an effort. -- Michal Hocko SUSE Labs