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Re: [Xen-devel] How does the numa flag affect memory allocation?

It is my understanding that, with numa=on, Xen will try to allocate memory for a para VM from the same node as the CPUs that the VM's procs are pinned to.
Thats true for HVM guests, too.
Thus, in a multi-node system, if we specify a pinning to
a specific node's CPUs in a VM's config file, Xen will allocate the VM's initial memory from that same node at startup.
My question is: does this location preference happen for all subsequent memory allocation? In other words, if I boot a VM configured with some initial memory and pinned to CPUs in node-X, change the pinning of the VM's procs to CPUs in node-Y, and then use "xm mem-set" to allocate more memory, does this new memory come from node-Y?
AFAIK ballooing and NUMA are in the moment mutually exclusive.

Currently I am working on NUMA PV guest support (multiple nodes within a
guest). I posted preliminary patches for HVM guests in August.
If you want to help, you are invited ;-)


Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 277-84917
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