Messages in this thread | | | Date | Tue, 10 Jul 2007 16:50:51 +0100 | Subject | Re: -mm merge plans -- anti-fragmentation | From | (Mel Gorman) |
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On (10/07/07 20:38), KAMEZAWA Hiroyuki didst pronounce: > On Tue, 10 Jul 2007 12:12:02 +0100 > mel@skynet.ie (Mel Gorman) wrote: > > > For (2), we need some method for specifing the range we will remove. For doing that, > > > ZONE seems to be good candidate. Now we use "kernelcore=" boot option to create > > > ZONE_MOVABLE by hand. > > > > At the risk of putting you on the spot, do you mind saying whether the > > grouping pages by mobility and ZONE_MOVABLE patches are going in the > > direction you want or should something totally different be done? If > > they are going the right direction, is there anything critical that is > > missing right now? > > > "grouping pages by mobility and ZONE_MOVABLE" things are what I want. And > I want to go with them. But I know some people doesn't want to increase # > of zones. It is my concern.
I'm not overly keen on increasing the number of zones either but it is a simplier approach, solves some of the problems and is less intrusive than grouping pages by mobility so it's a reasonable starting point.
> I know ZONE_MOVABLE works well but there are people who don't want new zone. > So making ZONE_MOVABLE as configurable will be good thing, as Nick Piggin pointed. >
I tested your zone-configurable patch and they appear to work. Your patch builds whether ZONE_MOVABLE is available or not and ZONE_MOVABLE is only available when the config option is set. It is also considerably cleaner than the patch I put together for a configurable ZONE_MOVABLE which is too ugly to live in comparison.
> About my other concerns , see node hotplug (below). > > > > But this is the first step. I know Intel guy posted > > > his idea to specify Hotpluggable-Memory range in SRAT (by firmware). > > > > There may be additional work required to make this play nicely with > > ZONE_MOVABLE but it shouldn't be anything fundamental. > > > yes. And I don't know his idea about SRAT is acceped in firmware comunity or not. > For now, kernelcore= works enough for memory hotplug. >
Sounds good.
> > > And I think that > > > other method may be introduced for node-hotplug. > > > > > > > Same as above really. If the node contains one zone - ZONE_MOVABLE, it > > would work for unplugging. > > > Our concern on node hotplug is "bootmem" and hashtable , pgdata, memmap etc.... > NUMA initilization (of each arch) includes something complicated. > But this is not directly related to ZONE_MOVABLE things I think. > It's node-hotplug problem. > We are now consdiering hot-add nodes after initcalls(). >
I don't see off-hand how it's so different from normal memory hot-add but I'll take your word for it. I'll keep an eye out for patches related to it.
Thanks
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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