Re: [Qemu-devel] vhost-user: broken mem regions

[Damjan Marion (damarion)]

On 25 Jun 2014, at 17:29, Michael S. Tsirkin <address@hidden> wrote:

> On Wed, Jun 25, 2014 at 02:57:52PM +0000, Damjan Marion (damarion) wrote:
>> 
>> On 25 Jun 2014, at 16:27, Michael S. Tsirkin <address@hidden> wrote:
>> 
>>> On Wed, Jun 25, 2014 at 02:20:56PM +0000, Damjan Marion (damarion) wrote:
>>>> 
>>>> On 25 Jun 2014, at 16:13, Nikolay Nikolaev <address@hidden> wrote:
>>>> 
>>>>>>> - it will require changes on the user side also
>>>>>> 
>>>>>> why would it?
>>>>>> format seems unchanged, right?
>>>>> 
>>>>> yes, but it will happen that multiple regions have same FD so call to 
>>>>> mmap()
>>>>> should look different, I’m still playing with this on user side...
>>>>> but then you shoudl somehow accumulate the sizes and send just a single 
>>>>> fd, something along these lines. 
>>>> 
>>>> Yes, so I’m not very happy with that approach and looking if there is 
>>>> better proposal, 
>>>> or at least wider agreement how to address this issue.
>>>> 
>>>> Damjan
>>> 
>>> still not sure what the issue is ...
>>> 
>> 
>> No issue, just additional logic is needed on user side to calculate total 
>> size of shared regions and call mmap() once per FD.
>> 
>> Agree?
> 
> why not just call it multiple times? AFAIK linux handles this just fine.

I need to specify size when calling mmap(), so i need to run trough all regions 
and sum sizes before calling mmap().