From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 758A821214948 for ; Thu, 18 Apr 2019 05:45:26 -0700 (PDT) From: Jeff Moyer Subject: Re: [PATCH v6 00/12] mm: Sub-section memory hotplug support References: <155552633539.2015392.2477781120122237934.stgit@dwillia2-desk3.amr.corp.intel.com> <20190417150331.90219ca42a1c0db8632d0fd5@linux-foundation.org> Date: Thu, 18 Apr 2019 08:45:10 -0400 In-Reply-To: (Dan Williams's message of "Wed, 17 Apr 2019 19:09:12 -0700") Message-ID: MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: Michal Hocko , David Hildenbrand , linux-nvdimm , Linux Kernel Mailing List , stable , Linux MM , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Andrew Morton , Vlastimil Babka , osalvador@suse.de List-ID: Dan Williams writes: >> On Wed, Apr 17, 2019 at 3:59 PM Dan Williams wrote: >> >> On Wed, Apr 17, 2019 at 3:04 PM Andrew Morton wrote: >> > >> > On Wed, 17 Apr 2019 11:38:55 -0700 Dan Williams 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. > > I'm also hoping Jeff can give a tested-by for the customer scenarios > that fall over with the current implementation. Sure. I'll also have a look over the patches. -Jeff _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm 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=unavailable 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 DE3B7C10F0E for ; Thu, 18 Apr 2019 12:45:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B683C2183E for ; Thu, 18 Apr 2019 12:45:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388992AbfDRMp0 (ORCPT ); Thu, 18 Apr 2019 08:45:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43032 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726162AbfDRMp0 (ORCPT ); Thu, 18 Apr 2019 08:45:26 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 83FA681129; Thu, 18 Apr 2019 12:45:25 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6CC6519C65; Thu, 18 Apr 2019 12:45:11 +0000 (UTC) From: Jeff Moyer To: Dan Williams Cc: Andrew Morton , David Hildenbrand , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Logan Gunthorpe , Toshi Kani , Michal Hocko , Vlastimil Babka , stable , Linux MM , linux-nvdimm , Linux Kernel Mailing List , osalvador@suse.de Subject: Re: [PATCH v6 00/12] mm: Sub-section memory hotplug support References: <155552633539.2015392.2477781120122237934.stgit@dwillia2-desk3.amr.corp.intel.com> <20190417150331.90219ca42a1c0db8632d0fd5@linux-foundation.org> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Thu, 18 Apr 2019 08:45:10 -0400 In-Reply-To: (Dan Williams's message of "Wed, 17 Apr 2019 19:09:12 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 18 Apr 2019 12:45:26 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dan Williams writes: >> On Wed, Apr 17, 2019 at 3:59 PM Dan Williams wrote: >> >> On Wed, Apr 17, 2019 at 3:04 PM Andrew Morton wrote: >> > >> > On Wed, 17 Apr 2019 11:38:55 -0700 Dan Williams 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. > > I'm also hoping Jeff can give a tested-by for the customer scenarios > that fall over with the current implementation. Sure. I'll also have a look over the patches. -Jeff