Re: [PATCH v11 3/4] softmmu/dirtylimit: implement virtual CPU throttle

[Peter Xu]

On Thu, Jan 20, 2022 at 06:39:01PM +0800, Hyman Huang wrote:
> > It only runs once per second so it shouldn't bring a lot of differences, but
> > I'm also wondering whether we should also turn that temporarily off too when
> > dirtylimit is enabled - we can simply let it keep sleeping if dirtylimit is 
> > in
> > service.
> Does this work ok when dirtylimit and migration happens concurrently?
> Migration may fetch the aged dirty bitmap info from slot if we turn reaper
> thread off. As you metioned above, reaper thread only runs once per second.
> Is it more suitable for not touching the reaper thread logic?

Yes I think it'll still work, as migration will do explicit sync/collect after
each iteration.  See kvm_log_sync_global().

In short, you shouldn't touch the rest of the kvm_dirty_ring_reap() callers,
they'll always flush all the rings.

But it'll be nicer if you will try it out. :)

-- 
Peter Xu