Messages in this thread | | | Date | Wed, 14 Aug 2013 14:22:22 -0400 | From | KOSAKI Motohiro <> | Subject | Re: [PATCH part5 0/7] Arrange hotpluggable memory as ZONE_MOVABLE. |
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(8/12/13 1:23 PM), H. Peter Anvin wrote: > On 08/12/2013 10:01 AM, Tang Chen wrote: >>> >>>> I'm just thinking of a more extreme case. For example, if a machine >>>> has only one node hotpluggable, and the kernel resides in that node. >>>> Then the system has no hotpluggable node. >>> >>> Yeah, sure, then there's no way that node can be hotpluggable and the >>> right thing to do is booting up the machine and informing the userland >>> that memory is not hotpluggable. >>> >>>> If we can prevent the kernel from using hotpluggable memory, in such >>>> a machine, users can still do memory hotplug. >>>> >>>> I wanted to do it as generic as possible. But yes, finding out the >>>> nodes the kernel resides in and make it unhotpluggable can work. >>> >>> Short of being able to remap memory under the kernel, I don't think >>> this can be very generic and as a compromise trying to keep as many >>> hotpluggable nodes as possible doesn't sound too bad. >> >> I think making one of the node hotpluggable is better. But OK, it is >> no big deal. There won't be such machine in reality, I think. :) >> > > The user may very well have configured a system with mirrored memory for > the kernel node as that will be non-hotpluggable, but not for the > others. One can wonder how much that actually buys in real life, but > still...
Note. Such system is much cheaper than full memory mirroring system. That's one of reason why server vendors are interesting in hot plugging.
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