[RFC PATCH v2 0/8] KVM: arm64: Implement SW/HW combined dirty log

[Oliver Upton]

On Mon, Sep 18, 2023 at 09:55:22AM +0000, Shameerali Kolothum Thodi wrote:

[...]

> > Sorry, this was rather nonspecific. I was describing the pre-copy
> > strategies we're using at Google (out of tree). We're carrying patches
> > to use EPT D-bit for exitless dirty tracking.
> 
> Just curious, how does it handle the overheads associated with scanning for
> dirty pages and the convergence w.r.t high rate of dirtying in exitless mode? 

A pool of kthreads, which really isn't a good solution at all. The
'better' way to do it would be to add some back pressure to the guest
such that your pre-copy transfer can converge with the guest and use the
freed up CPU time to manage the dirty state.

But hopefully we can make that a userspace issue.

-- 
Thanks,
Oliver