Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers

[Michael S. Tsirkin]

On Mon, Jan 18, 2010 at 04:52:10PM +0200, Avi Kivity wrote:
> On 01/18/2010 04:44 PM, Michael S. Tsirkin wrote:
>>
>>    
>>>> The point is that clients can be registered at any point.
>>>>
>>>> A client that registered when memory is present needs to
>>>> be notified about it.
>>>>
>>>>        
>>> It looks very expensive.
>>>      
>> Shouldn't be hard to optimize ...
>>    
>
> It's O(memory size), which can be very big.

cpu_register_physical_memory_offset already is O(memory size) btw.

>>> Maybe we mandate clients be registered at init-time?
>>>      
>>
>> This might be tricky - vhost currently only registers when the
>> first device is hot-added.
>>    
>
> I see.
>
> Maybe coalesce adjacent pages and call the callback with the ranges?

Hmm, it turns out to be tricky: it seems whether we can do this
really depends on what get_ram_ptr returns ...
Can't we just rely on callback to do the coalescing?


> -- 
> error compiling committee.c: too many arguments to function