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

[David Hildenbrand <david@redhat.com>]

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