Re: [Qemu-devel] [PATCH v3 10/12] kvm: Introduce slots lock for memory listener

[Peter Xu <peterx@redhat.com>]

On Thu, May 30, 2019 at 05:40:38PM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (peterx@redhat.com) wrote:
> > Introduce KVMMemoryListener.slots_lock to protect the slots inside the
> > kvm memory listener.  Currently it is close to useless because all the
> > KVM code path now is always protected by the BQL.  But it'll start to
> > make sense in follow up patches where we might do remote dirty bitmap
> > clear and also we'll update the per-slot cached dirty bitmap even
> > without the BQL.  So let's prepare for it.
> > 
> > We can also use per-slot lock for above reason but it seems to be an
> > overkill.  Let's just use this bigger one (which covers all the slots
> > of a single address space) but anyway this lock is still much smaller
> > than the BQL.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> 
> No one ever frees it? Huh OK, in that case if no one ever frees the
> listener then I guess you don't need to cleanup the lock.

Yeh not the first time I see something keeps forever in QEMU (in most
cases which won't hurt :).

I'll just leave it to the patch where all things are cleaned up.

> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Thanks,

-- 
Peter Xu