Messages in this thread |  | | Date | Wed, 16 Jan 2013 22:03:14 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH v5 0/5] Add movablecore_map boot option |
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On 01/16/2013 09:08 PM, Yasuaki Ishimatsu wrote: > > I thought about the method of specifying the node. But I think > this method is inconvenience. Node number is decided by OS. > So the number is changed easily. > > for example: > > o exmaple 1 > System has 3 nodes: > node0, node1, node2 > > When user remove node1, the system has: > node0, node2 > > But after rebooting the system, the system has: > node0, node1 > > So node2 becomes node1. > > o example 2: > System has 2 nodes: > 0x40000000 - 0x7fffffff : node0 > 0xc0000000 - 0xffffffff : node1 > > When user add a node wchih memory range is [0x80000000 - 0xbfffffff], > system has: > 0x40000000 - 0x7fffffff : node0 > 0xc0000000 - 0xffffffff : node1 > 0x80000000 - 0xbfffffff : node2 > > But after rebooting the system, the system's node may become: > 0x40000000 - 0x7fffffff : node0 > 0x80000000 - 0xbfffffff : node1 > 0xc0000000 - 0xffffffff : node2 > > So node nunber is changed. > > Specifying node number may be easy method than specifying memory > range. But if user uses node number for specifying removable memory, > user always need to care whether node number is changed or not at > every hotplug operation. >
Well, there are only two options:
1. The user doesn't care which nodes are movable. In that case, the user may just want to specify a target as a percentage of memory to make movable -- effectively a "slider" on the performance vs. reliability spectrum. The kernel can then assign nodes arbitrarily.
2. If the user *does* care which nodes are movable, then the user needs to be able to specify that *in a way that makes sense to the user*. This may mean involving the DMI information as well as SRAT in order to get "silk screen" type information out.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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