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Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA bi
From: |
Chris Wright |
Subject: |
Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding |
Date: |
Tue, 8 Nov 2011 09:33:04 -0800 |
User-agent: |
Mutt/1.5.20 (2009-08-17) |
* Alexander Graf (address@hidden) wrote:
> On 29.10.2011, at 20:45, Bharata B Rao wrote:
> > As guests become NUMA aware, it becomes important for the guests to
> > have correct NUMA policies when they run on NUMA aware hosts.
> > Currently limited support for NUMA binding is available via libvirt
> > where it is possible to apply a NUMA policy to the guest as a whole.
> > However multinode guests would benefit if guest memory belonging to
> > different guest nodes are mapped appropriately to different host NUMA nodes.
> >
> > To achieve this we would need QEMU to expose information about
> > guest RAM ranges (Guest Physical Address - GPA) and their host virtual
> > address mappings (Host Virtual Address - HVA). Using GPA and HVA, any
> > external
> > tool like libvirt would be able to divide the guest RAM as per the guest
> > NUMA
> > node geometry and bind guest memory nodes to corresponding host memory nodes
> > using HVA. This needs both QEMU (and libvirt) changes as well as changes
> > in the kernel.
>
> Ok, let's take a step back here. You are basically growing libvirt into a
> memory resource manager that know how much memory is available on which nodes
> and how these nodes would possibly fit into the host's memory layout.
>
> Shouldn't that be the kernel's job? It seems to me that architecturally the
> kernel is the place I would want my memory resource controls to be in.
I think that both Peter and Andrea are looking at this. Before we commit
an API to QEMU that has a different semantic than a possible new kernel
interface (that perhaps QEMU could use directly to inform kernel of the
binding/relationship between vcpu thread and it's memory at VM startuup)
it would be useful to see what these guys are working on...
thanks,
-chris
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding,
Chris Wright <=
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding, Bharata B Rao, 2011/11/21
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding, Peter Zijlstra, 2011/11/21
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding, Anthony Liguori, 2011/11/21
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding, Andrea Arcangeli, 2011/11/23
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding, Alexander Graf, 2011/11/23
- Re: [Qemu-devel] [RFC PATCH] Exporting Guest RAM information for NUMA binding, Andrea Arcangeli, 2011/11/23