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[209.85.220.65]) by mx.google.com with SMTPS id l1sor139007otk.47.2019.06.20.09.30.21 for (Google Transport Security); Thu, 20 Jun 2019 09:30:21 -0700 (PDT) Received-SPF: pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=IbYvmcN3; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=DApYrgtFGUX8hglw1AcOz6adgUtgKXSMo50u9kqGqWo=; b=IbYvmcN3FD1XsFJRWLBVeAh4cj+ztsE2rAJY2j9X45js8FuU/UPlkV5Z4mXnvi7Y7S A1GJpNUvJJbYn4ayjrn7/ANF+NiX7qKfqVlzDYpeflENEtIxLPu+qyys3bQLnsGfTQ1q nP6mTojxuOtLIWObuYkjJyA/1wtWC7fvvWuTmmiY8UwiqIT0/aeMmX6iPRbPwOg5iGPr uvfM5n2Dc7iiy1RvSAtGN0+PsX0kiVynUGI3ramtVIYzCGNtSNnR70SGPuHH87OdZOvD shvfqPmJ4PpbxFg34W9zwV3aCJNPq3GMuGB4dV59hH1kuK1Ja8KmFwrH/fL/dTGr3744 /wLg== X-Google-Smtp-Source: APXvYqxIllarlavyR5g1oQ37eeWGGe9Qov4pSV/b7aFTtPwH8mY5U/JzeG/yRiJUeWSkE5MXZLJELq2eNsiljKeKmTU= X-Received: by 2002:a9d:7b48:: with SMTP id f8mr14032030oto.207.1561048221363; Thu, 20 Jun 2019 09:30:21 -0700 (PDT) MIME-Version: 1.0 References: <156092349300.979959.17603710711957735135.stgit@dwillia2-desk3.amr.corp.intel.com> <874l4kjv6o.fsf@linux.ibm.com> In-Reply-To: <874l4kjv6o.fsf@linux.ibm.com> From: Dan Williams Date: Thu, 20 Jun 2019 09:30:10 -0700 Message-ID: Subject: Re: [PATCH v10 00/13] mm: Sub-section memory hotplug support To: "Aneesh Kumar K.V" Cc: Andrew Morton , David Hildenbrand , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Mike Rapoport , Jane Chu , Pavel Tatashin , Jonathan Corbet , Qian Cai , Logan Gunthorpe , Toshi Kani , Oscar Salvador , Jeff Moyer , Michal Hocko , Vlastimil Babka , stable , Wei Yang , Linux MM , linux-nvdimm , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" 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: On Thu, Jun 20, 2019 at 5:31 AM Aneesh Kumar K.V wrote: > > Dan Williams writes: > > > Changes since v9 [1]: > > - Fix multiple issues related to the fact that pfn_valid() has > > traditionally returned true for any pfn in an 'early' (onlined at > > boot) section regardless of whether that pfn represented 'System RAM'. > > Teach pfn_valid() to maintain its traditional behavior in the presence > > of subsections. Specifically, subsection precision for pfn_valid() is > > only considered for non-early / hot-plugged sections. (Qian) > > > > - Related to the first item introduce a SECTION_IS_EARLY > > (->section_mem_map flag) to remove the existing hacks for determining > > an early section by looking at whether the usemap was allocated from the > > slab. > > > > - Kill off the EEXIST hackery in __add_pages(). It breaks > > (arch_add_memory() false-positive) the detection of subsection > > collisions reported by section_activate(). It is also obviated by > > David's recent reworks to move the 'System RAM' request_region() earlier > > in the add_memory() sequence(). > > > > - Switch to an arch-independent / static subsection-size of 2MB. > > Otherwise, a per-arch subsection-size is a roadblock on the path to > > persistent memory namespace compatibility across archs. (Jeff) > > > > - Update the changelog for "libnvdimm/pfn: Fix fsdax-mode namespace > > info-block zero-fields" to clarify that the "Cc: stable" is only there > > as safety measure for a distro that decides to backport "libnvdimm/pfn: > > Stop padding pmem namespaces to section alignment", otherwise there is > > no known bug exposure in older kernels. (Andrew) > > > > - Drop some redundant subsection checks (Oscar) > > > > - Collect some reviewed-bys > > > > [1]: https://lore.kernel.org/lkml/155977186863.2443951.9036044808311959913.stgit@dwillia2-desk3.amr.corp.intel.com/ > > > You can add Tested-by: Aneesh Kumar K.V > for ppc64. Thank you! > BTW even after this series we have the kernel crash mentioned in the > below email on reconfigure. > > https://lore.kernel.org/linux-mm/20190514025354.9108-1-aneesh.kumar@linux.ibm.com > > I guess we need to conclude how the reserve space struct page should be > initialized ? Yes, that issue is independent of the subsection changes. I'll take a closer look.