Re: [Xen-devel] [RFC Patch v4 7/8] x86/hvm: bump the number of pages of shadow memory

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.12.17 at 08:50, <chao.gao@xxxxxxxxx> wrote:
> Each vcpu of hvm guest consumes at least one shadow page. Currently, only 256
> (for hap case) pages are pre-allocated as shadow memory at beginning. It would
> run out if guest has more than 256 vcpus and guest creation fails. Bump the
> number of shadow pages to 2 * HVM_MAX_VCPUS for hap case and 8 * HVM_MAX_VCPUS
> for shadow case.
> 
> This patch won't lead to more memory consumption for the size of shadow memory
> will be adjusted via XEN_DOMCTL_SHADOW_OP_SET_ALLOCATION according to the size
> of guest memory and the number of vcpus.

I don't understand this: What's the purpose of bumping the values if it won't 
lead
to higher memory consumption? Afaict there's be higher consumption at least
transiently. And I don't see why this would need doing independent of the 
intended
vCPU count in the guest. I guess you want to base your series on top on Andrew's
max-vCPU-s adjustments (which sadly didn't become ready in time for 4.11).

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel