From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 8 Oct 2007 12:01:23 -0700 From: Mark Gross Subject: Re: Hotplug memory remove Message-ID: <20071008190123.GC31906@linux.intel.com> Reply-To: mgross@linux.intel.com References: <1191253063.29581.7.camel@dyn9047017100.beaverton.ibm.com> <20071002011447.7ec1f513.kamezawa.hiroyu@jp.fujitsu.com> <20071005172128.GA19681@linux.intel.com> <20071006094115.8b488e55.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071006094115.8b488e55.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: pbadari@gmail.com, linux-mm@kvack.org, y-goto@jp.fujitsu.com List-ID: On Sat, Oct 06, 2007 at 09:41:15AM +0900, KAMEZAWA Hiroyuki wrote: > On Fri, 5 Oct 2007 10:21:28 -0700 > Mark Gross wrote: > > > > I'm not sure about this...does this memory is in ZONE_MOVABLE ? > > > If not ZONE_MOVABLE, offlining can be fail because of not-removable > > > kernel memory. > > > > How could I mark a nid's worth of memory as ZONE_MOVABLE? I've been > > reading through this code and it appears to somewhat arbitrarily choose > > some portion of the memory to be ZONE_MOVABLE per pxm and some kernel > > parameters. But I'm having a hard time finding the proper place to set > > up the nodes. > > > It's not available now. Thats a usability challenge. What use scenarios do you have for memory unplug then? I'd like to mimic your stuff if I can. > > 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? > > If your firmware (efi?) doesn't show memory for hot removal at boot time, > this idea will be simpler.. how so? thanks, --mgross -- 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