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 6BCA0C282DD for ; Thu, 18 Apr 2019 12:45:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0AAA42183E for ; Thu, 18 Apr 2019 12:45:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0AAA42183E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6382F6B0008; Thu, 18 Apr 2019 08:45:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5E6E26B000A; Thu, 18 Apr 2019 08:45:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4D7D26B000C; Thu, 18 Apr 2019 08:45:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) by kanga.kvack.org (Postfix) with ESMTP id 29DF96B0008 for ; Thu, 18 Apr 2019 08:45:28 -0400 (EDT) Received: by mail-qt1-f197.google.com with SMTP id n1so1878534qte.12 for ; Thu, 18 Apr 2019 05:45:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:references:date:in-reply-to:message-id:user-agent :mime-version; bh=V6+AwqFlWgmo/f1d5Sr1wG1FplZRlRHmIy7RCmGRmNA=; b=iH8wJ9dbWje1aQWep1zlDY+aZi2a+cwrsvOQGnwdQfNW+7SHtuyTRddhRfkMEfYl2G LTfwr86jzCyBqEpqy+NsmXKCHZhVTmLC73AUNDwgUHC3YweeuLpGh3OOz1kUxXssNrVC NwSCq1xuJJ/ZW8k/eBZAg3TkO9qhRPwiGKVDgrE13XLrHzA8a2Wuon1zMd79l2vjcHjS THvxpJ8hVcmZNJV7EF6aYjlqKNMFMaYc9wGRGESNeVC/iVylCxkxgPcCUJiJRfxVoxkB 1pZhLb1eyhEA0HkTyWVTaoHUBPzPkNib3c0EKU7W4XL0S+ARJ3DwKD8xq9kSloKmZPBO 9SWw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jmoyer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: APjAAAUfE0s5gKpL/BYOtiqBsb+gpl9g0rYPlKPiWq8r0F7iHEbn9fb1 Tp5PO4LY2sS8p+bsnQRJlpWBmnjpSlUsRuejprwejuikyoAcFCRH5N7Tz820BbxmoiIYGoNPyXk PXONDuCASDikRzmDi8jzWN/tJOdgIDsSCml2oa2xyh9poxpw8BIl+thoiwTmrYGv8ww== X-Received: by 2002:a37:7c87:: with SMTP id x129mr8174161qkc.311.1555591527838; Thu, 18 Apr 2019 05:45:27 -0700 (PDT) X-Google-Smtp-Source: APXvYqx7K6Gco0E4zKGW+yYKZ34b7XbKRYvnc1grFSL0JUUy7jG2y5Z6t/pqt/6+IGzm+rp1JIJJ X-Received: by 2002:a37:7c87:: with SMTP id x129mr8174120qkc.311.1555591527070; Thu, 18 Apr 2019 05:45:27 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555591527; cv=none; d=google.com; s=arc-20160816; b=lINbMtjMds0f4jh/SPrTkylBYNA6PTA9KIzMVAxqxNd7BuhAiH5cZPcYkS6dDTrPwj dADtWe8yaNL2W+IAsrUsBsbVP8Tjudya4hN8wg7jHGl5Pdk6i1atTX0LhlELOOuRsHAZ YhjZwuKZiSsVWPbrmEvRhwdrCjKPA3jjVsxGvcNtm16yj7txXZuAHXE5kjRY2k5STnLQ +9g5XiJaSaCkbvcYKWWqv58wryLAIHUxyulec2ewDNaaO+lhvL2XnDLBirR+8KDEbS8n s85q0CLf8W301jngavkmOBE8c/1PxRl5MKQ24TpPPhtvzMTE6nvNUWT4zqKT1+ErXdJo SFfw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:message-id:in-reply-to:date:references :subject:cc:to:from; bh=V6+AwqFlWgmo/f1d5Sr1wG1FplZRlRHmIy7RCmGRmNA=; b=imklo8SfPTBVlKO9TA58VA0vHWb7NS5kuczIe6UFlP/+eEASmetN4MmKFeqncjyZYL BJ1tIeW0vZFte+3mV5RIl2GAje8qhnDWJH3+ehUUrYZDPgPJ8k2CSH329zg7GrnbNfcs bA3cXfGSPMFM+ozaWHwQrO3YVAgvv5jVv3v3sdRMpo5Jpmbrh2wkBL5AxKKoR78fNgJu GoWEqRCpklel+MjM0EWL4qpqMC+6XCTceeXePM+9GO37yA+Bd+qTtVtm0jmp7a5cFNfj dZkVM9le3Ew5f2nciCmYjGXCIoG/RqfofeK0KwCGoITs0PQs45YEcEaSK0tOjyPb97Ij C/yQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jmoyer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id e33si1516500qvh.73.2019.04.18.05.45.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Apr 2019 05:45:27 -0700 (PDT) Received-SPF: pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jmoyer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jmoyer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com 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) 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: 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