Re: [PATCH v7 6/6] hostmem: Handle remapping of RAM

[David Hildenbrand]

On 04.02.25 18:58, Peter Xu wrote:
> On Tue, Feb 04, 2025 at 06:50:17PM +0100, David Hildenbrand wrote:
> > >        /*
> > > @@ -595,6 +628,7 @@ static const TypeInfo host_memory_backend_info = {
> > >        .instance_size = sizeof(HostMemoryBackend),
> > >        .instance_init = host_memory_backend_init,
> > >        .instance_post_init = host_memory_backend_post_init,
> > > +    .instance_finalize = host_memory_backend_finalize,
> > >        .interfaces = (InterfaceInfo[]) {
> > >            { TYPE_USER_CREATABLE },
> > >            { }
> > > diff --git a/include/system/hostmem.h b/include/system/hostmem.h
> > > index 5c21ca55c0..170849e8a4 100644
> > > --- a/include/system/hostmem.h
> > > +++ b/include/system/hostmem.h
> > > @@ -83,6 +83,7 @@ struct HostMemoryBackend {
> > >        HostMemPolicy policy;
> > >        MemoryRegion mr;
> > > +    RAMBlockNotifier ram_notifier;
> > >    };
> >
> > Thinking about Peters comment, it would be a nice improvement to have a
> > single global memory-backend notifier that looks up the fitting memory
> > backend, instead of having one per memory backend.
>
> Yes, this could also avoid O(N**2).

Ah, and now I remember where these 3 patches originate from: virtio-mem 
handling.

For virtio-mem I want to register also a remap handler, for example, to 
perform the custom preallocation handling.

So there will be at least two instances getting notified (memory 
backend, virtio-mem), and the per-ramblock one would have only allowed 
to trigger one (at least with a simple callback as we have today for 
->resize).

--
Cheers,

David / dhildenb