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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