Il 26/07/2013 09:38, Igor Mammedov ha scritto: > Perhaps denying memory add and suggesting node migration to a node with > more memory would be right approach, otherwise user is bound to be hit by > cross node penalty.
Or better, the user can first change the policy from "bind" to "preferred", and then hotplug. >> > I agree that specifying the policy on every hotplug complicates >> > management and may be overkill. But then, most guests are not NUMA at >> > all and you would hardly perceive the difference, you would just have to >> > separate >> > >> > set-mem-policy 0 size=2G >> > device_add dimm,slot=0 > I'm confused, size is inherent property of generic DimmDevice and policies > are NUMA specific of node. No, the size is not a property of the DimmDevice, it is a property of the host object that backs the DimmDevice. This is like the size is not a property of a disk, but rather of the image that backs it. Now, there may be a good reason to remove the host/guest distinction in the case of memory, but I'm still not sure this is the case. In the case of NUMA policies, I talked to Andrea Arcangeli and indeed his suggestion was to have a single policy per guest node (typically bind or preferred if guest node size <= host node size, interleave if guest node size > host node size). However, there are other properties of the memory object (e.g. hugetlbfs path) that could be customized for every slot. Paolo > If there is need for per DIMM policies, I'd store NUMA specific policy inside > object that implements it (allocates memory), and apply them to DIMM when > it's realized. > > set-mem-policy nodeid=X,mem-hostnodes=Z,dev=dimmY > device_add dimm,id=dimmY,size=2G,node=X >
