From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 09 Oct 2007 19:51:59 +0900 From: Yasunori Goto Subject: Re: Hotplug memory remove In-Reply-To: <20071009101003.cb9fdc9f.kamezawa.hiroyu@jp.fujitsu.com> References: <20071008190123.GC31906@linux.intel.com> <20071009101003.cb9fdc9f.kamezawa.hiroyu@jp.fujitsu.com> Message-Id: <20071009193217.4270.Y-GOTO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: mgross@linux.intel.com, pbadari@gmail.com, linux-mm@kvack.org List-ID: > > > One idea is to ignore memory of some PXMs specified by kerenel boot param. > > > Later, you can hot-add specified PXM memory as MOVABLE. > > > Then, boot sequence will be > > > -- > > > bootstrap , ignore some memory here. > > > init memory, driver, etc > > > hot-add ignored memory > > > online hot-added memory by user scripts. (from rc script ?) > > > --y > > > For doing this, we need > > > - a switch to hot-add memory as MOVABLE (will be easy patch) > > > - a code for ignoring memory at boot but remember them for later hotadd > > > (maybe needs arch specific codes) > > > - a code for hot add memory before rc script (initcall is suitable ?) > > > > > > Needs some amount of arch-specific codes, but maybe simple. > > > Why I recommend above is it will be complex to avoid some PXM's memory > > > to be used as bootmem or for some other purpose(slab, hash, etc...). > > > > I have the boot memory allocations or off-lineable-memory taken care of. > > I can see how the above would work, but I worry that it feels a bit > > hackish. > > > > BTW Is this how memory hot remove is expected to be used? > > > I think above is a simple way to go. How about you ? > Goto-san. > I don't want to make memory-initialization too complicated. Hmm. At first, I agreed with you. But I'm a bit worry about it too now. When movable-memory is specified by boot option, I guess something wrong case will occur like followings. ex) Movable node is specified by boot-option as "movable_node=2" on 4 node box. 1) boot up with 2 movable node and 2 non-movable node. 2) remove those 2 nodes physically. 3) system must be removed by some reasons. 4) system can't boot up due to only 2 MOVABLE nodes! It depends how "movable area" is specified. please take care. Bye. -- Yasunori Goto -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org