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Re: [Qemu-ppc] [RFC PATCH v5 6/6] spapr: Don't allow memory hotplug to m
Bharata B Rao
Re: [Qemu-ppc] [RFC PATCH v5 6/6] spapr: Don't allow memory hotplug to memory less nodes
Fri, 26 Jun 2015 11:13:14 +0530
On Fri, Jun 26, 2015 at 03:33:29PM +1000, David Gibson wrote:
> On Thu, Jun 25, 2015 at 11:44:15AM +0530, Bharata B Rao wrote:
> > Currently PowerPC kernel doesn't allow hot-adding memory to memory-less
> > node, but instead will silently add the memory to the first node that has
> > some memory. This causes two unexpected behaviours for the user.
> > Memory gets hotplugged to a different node than what the user specified.
> > Since pc-dimm subsystem in QEMU still thinks that memory belongs to
> > memory-less node, a reboot will set things accordingly and the previously
> > hotplugged memory now ends in the right node. This appears as if some
> > memory moved from one node to another.
> > So until kernel starts supporting memory hotplug to memory-less
> > nodes, just prevent such attempts upfront in QEMU.
> > Signed-off-by: Bharata B Rao <address@hidden>
> I presume you're talking about host kernel limitations here?
No, this is a guest kernel limitation. Pls refer to the related discussions
about this here:
> If that does get changed in future we'll need some sort of ugly compat
> test in qemu to see if the new kernel can handle it, but there's no
> way to avoid that, so.
Yeah, I see that.
- [Qemu-ppc] [PATCH v5 3/6] spapr: Support ibm, dynamic-reconfiguration-memory, (continued)
- [Qemu-ppc] [PATCH v5 3/6] spapr: Support ibm, dynamic-reconfiguration-memory, Bharata B Rao, 2015/06/25
- [Qemu-ppc] [PATCH v5 5/6] spapr: Memory hotplug support, Bharata B Rao, 2015/06/25
- [Qemu-ppc] [PATCH v5 4/6] spapr: Make hash table size a factor of maxram_size, Bharata B Rao, 2015/06/25
- [Qemu-ppc] [PATCH v5 2/6] spapr: Add LMB DR connectors, Bharata B Rao, 2015/06/25
- [Qemu-ppc] [RFC PATCH v5 6/6] spapr: Don't allow memory hotplug to memory less nodes, Bharata B Rao, 2015/06/25
- Re: [Qemu-ppc] [PATCH v5 0/6] Memory hotplug for PowerPC sPAPR guests, David Gibson, 2015/06/26