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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 CD13FC10F14 for ; Tue, 23 Apr 2019 13:17:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99D2A2175B for ; Tue, 23 Apr 2019 13:17:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727666AbfDWNRR (ORCPT ); Tue, 23 Apr 2019 09:17:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:60998 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726421AbfDWNRR (ORCPT ); Tue, 23 Apr 2019 09:17:17 -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 8A81EABB1; Tue, 23 Apr 2019 13:17:15 +0000 (UTC) Message-ID: <1556025416.2956.0.camel@suse.de> Subject: Re: [PATCH v6 00/12] mm: Sub-section memory hotplug support From: Oscar Salvador To: Dan Williams , Andrew Morton Cc: David Hildenbrand , =?ISO-8859-1?Q?J=E9r=F4me?= Glisse , Logan Gunthorpe , Toshi Kani , Jeff Moyer , Michal Hocko , Vlastimil Babka , stable , Linux MM , linux-nvdimm , Linux Kernel Mailing List Date: Tue, 23 Apr 2019 15:16:56 +0200 In-Reply-To: References: <155552633539.2015392.2477781120122237934.stgit@dwillia2-desk3.amr.corp.intel.com> <20190417150331.90219ca42a1c0db8632d0fd5@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, 2019-04-17 at 15:59 -0700, Dan Williams wrote: > On Wed, Apr 17, 2019 at 3:04 PM Andrew Morton org> wrote: > > > > On Wed, 17 Apr 2019 11:38:55 -0700 Dan Williams > el.com> wrote: > > > > > The memory hotplug section is an arbitrary / convenient unit for > > > memory > > > hotplug. 'Section-size' units have bled into the user interface > > > ('memblock' sysfs) and can not be changed without breaking > > > existing > > > userspace. The section-size constraint, while mostly benign for > > > typical > > > memory hotplug, has and continues to wreak havoc with 'device- > > > memory' > > > use cases, persistent memory (pmem) in particular. Recall that > > > pmem uses > > > devm_memremap_pages(), and subsequently arch_add_memory(), to > > > allocate a > > > 'struct page' memmap for pmem. However, it does not use the > > > 'bottom > > > half' of memory hotplug, i.e. never marks pmem pages online and > > > never > > > exposes the userspace memblock interface for pmem. This leaves an > > > opening to redress the section-size constraint. > > > > v6 and we're not showing any review activity. Who would be > > suitable > > people to help out here? > > There was quite a bit of review of the cover letter from Michal and > David, but you're right the details not so much as of yet. I'd like > to > call out other people where I can reciprocate with some review of my > own. Oscar's altmap work looks like a good candidate for that. Thanks Dan for ccing me. I will take a look at the patches soon. -- Oscar Salvador SUSE L3