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[37.188.169.187]) by smtp.gmail.com with ESMTPSA id lc18sm120397ejb.29.2020.07.24.00.28.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Jul 2020 00:28:23 -0700 (PDT) Date: Fri, 24 Jul 2020 09:28:21 +0200 From: Michal Hocko To: David Hildenbrand Cc: Roger Pau =?iso-8859-1?Q?Monn=E9?= , =?iso-8859-1?Q?J=FCrgen_Gro=DF?= , linux-kernel@vger.kernel.org, Boris Ostrovsky , Stefano Stabellini , Andrew Morton , xen-devel@lists.xenproject.org, linux-mm@kvack.org Subject: Re: [PATCH 3/3] memory: introduce an option to force onlining of hotplug memory Message-ID: <20200724072821.GD4061@dhcp22.suse.cz> References: <20200723084523.42109-1-roger.pau@citrix.com> <20200723084523.42109-4-roger.pau@citrix.com> <21490d49-b2cf-a398-0609-8010bdb0b004@redhat.com> <20200723122300.GD7191@Air-de-Roger> <20200723135930.GH7191@Air-de-Roger> <82b131f4-8f50-cd49-65cf-9a87d51b5555@suse.com> <20200723162256.GI7191@Air-de-Roger> <4ff380e9-4b16-4cd0-7753-c2b89bd8ac6b@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ff380e9-4b16-4cd0-7753-c2b89bd8ac6b@redhat.com> X-Rspamd-Queue-Id: 01F7D18022F37 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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 23-07-20 19:39:54, David Hildenbrand wrote: [...] > Yeah, might require some code churn. It just feels wrong to involve > buddy concepts (e.g., onlining pages, calling memory notifiers, exposing > memory block devices) and introducing hacks (forced onlining) just to > get a memmap+identity mapping+iomem resource. I think reserving such a > region during boot as suggested is the easiest approach, but I am > *absolutely* not an expert on all these XEN-specific things :) I am late to the discussion but FTR I completely agree. -- Michal Hocko SUSE Labs