From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Date: Tue, 21 Mar 2006 18:00:12 +0000 Subject: Re: [PATCH: 002/017]Memory hotplug for new nodes v.4.(change name Message-Id: <1142964013.10906.158.camel@localhost.localdomain> List-Id: References: <20060317162757.C63B.Y-GOTO@jp.fujitsu.com> <1142615538.10906.67.camel@localhost.localdomain> <20060318102653.57c6a2af.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20060318102653.57c6a2af.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: KAMEZAWA Hiroyuki Cc: y-goto@jp.fujitsu.com, akpm@osdl.org, tony.luck@intel.com, ak@suse.de, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mm@kvack.org On Sat, 2006-03-18 at 10:26 +0900, KAMEZAWA Hiroyuki wrote: > If *determine node* function is moved to arch specific parts, > memory hot add need more and more codes to determine paddr -> nid in arch > specific codes. Then, we have to add new paddr->nid function even if new nid is > passed by firmware. We *lose* useful information of nid from firmware if > add_memory() has just 2 args, (start, end). What I'm saying is that I'd like add_memory() to be just that, for adding memory. At some point in the process, you need to export the NUMA node layout to the rest of the system, to say which pages go in which node. I'm just saying that you should do that _before_ add_memory(). add_memory() should support adding memory to more than one node. If any hypervisor or hardware happens to have memory added in one contiguous chunk, it can not simply call add_memory(). _That_ firmware would be forced to do the NUMA parsing and figure out how many times to call add_memory(). Let me reiterate: the process of telling the system which pages are in which node should be separate from telling the system that there *are* currently pages there now. -- Dave