From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f197.google.com (mail-qk0-f197.google.com [209.85.220.197]) by kanga.kvack.org (Postfix) with ESMTP id 046836B03A0 for ; Fri, 7 Apr 2017 13:11:08 -0400 (EDT) Received: by mail-qk0-f197.google.com with SMTP id n80so14834653qke.8 for ; Fri, 07 Apr 2017 10:11:08 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id t21si5370916qta.36.2017.04.07.10.11.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 07 Apr 2017 10:11:06 -0700 (PDT) Date: Fri, 7 Apr 2017 13:10:59 -0400 From: Jerome Glisse Subject: Re: [HMM 01/16] mm/memory/hotplug: add memory type parameter to arch_add/remove_memory Message-ID: <20170407171055.GA16527@redhat.com> References: <20170405204026.3940-1-jglisse@redhat.com> <20170405204026.3940-2-jglisse@redhat.com> <20170407121349.GB16392@dhcp22.suse.cz> <20170407143246.GA15098@redhat.com> <20170407144504.GG16413@dhcp22.suse.cz> <20170407145740.GA15335@redhat.com> <20170407151105.GH16413@dhcp22.suse.cz> <20170407160959.GA15945@redhat.com> <20170407163737.GI16413@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="envbJBWh7q8WU6mo" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170407163737.GI16413@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, John Hubbard , Dan Williams , Naoya Horiguchi , David Nellans , Russell King , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Yoshinori Sato , Rich Felker , Chris Metcalf , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" --envbJBWh7q8WU6mo Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit On Fri, Apr 07, 2017 at 06:37:37PM +0200, Michal Hocko wrote: > On Fri 07-04-17 12:10:00, Jerome Glisse wrote: > > On Fri, Apr 07, 2017 at 05:11:05PM +0200, Michal Hocko wrote: > > > On Fri 07-04-17 10:57:43, Jerome Glisse wrote: > > > > On Fri, Apr 07, 2017 at 04:45:04PM +0200, Michal Hocko wrote: > > > > > On Fri 07-04-17 10:32:49, Jerome Glisse wrote: > > > > > > On Fri, Apr 07, 2017 at 02:13:49PM +0200, Michal Hocko wrote: > > > > > > > On Wed 05-04-17 16:40:11, Jerome Glisse wrote: > > > > > > > > When hotpluging memory we want more information on the type of memory. > > > > > > > > This is to extend ZONE_DEVICE to support new type of memory other than > > > > > > > > the persistent memory. Existing user of ZONE_DEVICE (persistent memory) > > > > > > > > will be left un-modified. > > > > > > > > > > > > > > My current hotplug rework [1] is touching this path as well. It is not > > > > > > > really clear from the chage why you are changing this and what are the > > > > > > > further expectations of MEMORY_DEVICE_PERSISTENT. Infact I have replaced > > > > > > > for_device with want__memblock [2]. I plan to repost shortly but I would > > > > > > > like to understand your modifications more to reduce potential conflicts > > > > > > > in the code. Why do you need to distinguish different types of memory > > > > > > > anyway. > > > > > > > > > > > > > > [1] http://lkml.kernel.org/r/20170330115454.32154-1-mhocko@kernel.org > > > > > > > [2] the current patchset is in git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git > > > > > > > branch attempts/rewrite-mem_hotplug-WIP > > > > > > > > > > > > This is needed for UNADDRESSABLE memory type introduced in patch 3 and > > > > > > the arch specific bits are in patch 4. Basicly for UNADDRESSABLE memory > > > > > > i do not want the arch code to create a linear mapping for the range > > > > > > being hotpluged. Adding memory_type in this patch allow to distinguish > > > > > > between different type of ZONE_DEVICE. > > > > > > > > > > Why don't you use __add_pages directly then? > > > > > > > > That's a possibility, i wanted to keep the arch code in the loop in case > > > > some arch wanted to do something specific. But it is unlikely to ever be > > > > use outside x86 and i don't think we will want to do anything more than > > > > skipping linear mapping. > > > > > > Hmm, I am looking closer and x86 stil updates max_pfn. Is this needed > > > or you are guaranteed to not cross the max_pfn? > > > > No guaranteed so yes i somewhat care about max_pfn, i do not care about > > any of its existing user last time i check but it might matter for some > > new user. > > OK, then we can add add_pages() which would do __add_pages by default > (#ifndef ARCH_HAS_ADD_PAGES) and x86 would override it do also call > update_end_of_memory_vars. This sounds easier to me than updating all > the archs and add something that most of them do not really care about. > > But I will not insist. If you think that your approach is better I will > not object. Something like attached patch ? > > Btw. is your series reviewed and ready to be applied to the mm tree? I > planed to post mine on Monday so I would like to know how do we > coordinate. I rebase on topo of yours or vice versa. Well v18 core patches were review by Mel, i did include all of his comment in v19 (i don't think i did miss any). I think Dan still want to look at patch 1 and 3 for ZONE_DEVICE. But i always welcome more review. I know Anshuman replied to this patch to improve a comments. Balbir had issue on powerpc because iomem_resource.end isn't clamped to MAX_PHYSMEM_BITS But that is all review i got so far on v19. I don't mind rebasing on top of your patchset. What ever is easier for Andrew i guess. Cheers, Jerome --envbJBWh7q8WU6mo Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: attachment; filename="0001-mm-memory_hotplug-add-add_pages-hotplug-without-line.patch" Content-Transfer-Encoding: 8bit --envbJBWh7q8WU6mo--