Re: [PATCH 1/1] KVM: PPC: Increase memslots to 320

[Paul Mackerras <paulus@ozlabs.org>]

On Wed, Nov 04, 2015 at 10:03:48AM +0100, Thomas Huth wrote:
> Only using 32 memslots for KVM on powerpc is way too low, you can
> nowadays hit this limit quite fast by adding a couple of PCI devices
> and/or pluggable memory DIMMs to the guest.
> x86 already increased the limit to 512 in total, to satisfy 256
> pluggable DIMM slots, 3 private slots and 253 slots for other things
> like PCI devices. On powerpc, we only have 32 pluggable DIMMs in

I agree with increasing the limit.  Is there a reason we have only 32
pluggable DIMMs in QEMU on powerpc, not more?  Should we be increasing
that limit too?  If so, maybe we should increase the number of memory
slots to 512?

> QEMU, not 256, so we likely do not as much slots as on x86. Thus

"so we likely do not need as many slots as on x86" would be better
English.

> setting the slot limit to 320 sounds like a good value for the
> time being (until we have some code in the future to resize the
> memslot array dynamically).
> And while we're at it, also remove the KVM_MEM_SLOTS_NUM definition
> from the powerpc-specific header since this gets defined in the
> generic kvm_host.h header anyway.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Paul.