Re: [PATCH] kvm: rename HINTS_DEDICATED to KVM_HINTS_REALTIME

Michael S. Tsirkin
2018-05-18T12:47:53Z

On Fri, May 18, 2018 at 11:41:23AM +0200, Paolo Bonzini wrote:
> On 17/05/2018 20:46, Eduardo Habkost wrote:
> > My understanding of the original patch is that the intention is
> > to tell the guest that it is very unlikely to be preempted, so it
> > can choose a more appropriate spinlock implementation. This
> > description implies that the guest will never be preempted, which
> > is much stronger guarantee.
> >
> > Isn't this new description incompatible with existing usage of
> > the hint, which might include people who just use vCPU pinning
> > but no mlock?
>
> If you use hugetlbfs and vhost-user you don't really need mlock for the
> QEMU process, do you? The QEMU process is not doing much in that case
> and hugetlbfs gives you pinned memory automatically.
>
> Paolo

Same with PCI device passthrough: VFIO pins all guest memory right now.

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MST