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

[Thomas Huth <thuth@redhat.com>]

On 04/11/15 10:03, 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
> QEMU, not 256, so we likely do not as much slots as on x86. Thus
> 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>
> ---
>  arch/powerpc/include/asm/kvm_host.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 887c259..89d387a 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -38,8 +38,7 @@
>  
>  #define KVM_MAX_VCPUS		NR_CPUS
>  #define KVM_MAX_VCORES		NR_CPUS
> -#define KVM_USER_MEM_SLOTS 32
> -#define KVM_MEM_SLOTS_NUM KVM_USER_MEM_SLOTS
> +#define KVM_USER_MEM_SLOTS 320
>  
>  #ifdef CONFIG_KVM_MMIO
>  #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
> 

Ping! ... any comments on this one?

 Thomas