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[209.132.183.28]) by mx.google.com with ESMTPS id m10si1332766qkg.37.2019.03.25.07.28.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Mar 2019 07:28:05 -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-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9480288304; Mon, 25 Mar 2019 14:28:04 +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 729CC842B2; Mon, 25 Mar 2019 14:28:02 +0000 (UTC) From: Jeff Moyer To: Michal Hocko Cc: Dan Williams , Andrew Morton , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Logan Gunthorpe , Toshi Kani , Vlastimil Babka , stable , Linux MM , linux-nvdimm , Linux Kernel Mailing List Subject: Re: [PATCH v5 00/10] mm: Sub-section memory hotplug support References: <155327387405.225273.9325594075351253804.stgit@dwillia2-desk3.amr.corp.intel.com> <20190322180532.GM32418@dhcp22.suse.cz> <20190325101945.GD9924@dhcp22.suse.cz> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Mon, 25 Mar 2019 10:28:00 -0400 In-Reply-To: <20190325101945.GD9924@dhcp22.suse.cz> (Michal Hocko's message of "Mon, 25 Mar 2019 11:19:45 +0100") 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 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 25 Mar 2019 14:28:04 +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: Michal Hocko writes: >> > and I would like to know that you are >> > not just shifting the problem to a smaller unit and a new/creative HW >> > will force us to go even more complicated. >> >> HW will not do this to us. It's software that has the problem. >> Namespace creation is unnecessarily constrained to 128MB alignment. > > And why is that a problem? A lack of documentation that this is a > requirement? Something will not work with a larger alignment? Someting > else? See this email for one user-visible problem: https://lore.kernel.org/lkml/x49imxbx22d.fsf@segfault.boston.devel.redhat.com/ Cheers, Jeff