Re: [RFC, PATCH 0/5] Going forward with Resource Management - A cpu controller

[Kirill Korotaev <dev@sw.ru>]

>>>>>Doesnt the ability to move tasks between groups dynamically affect
>>>>>(atleast) memory controller design (in giving up ownership etc)?
>>>>
>>>>we save object owner on the object. So if you change the container,
>>>>objects are still correctly charged to the creator and are uncharged
>>>>correctly on free.
>>>>
>>>
>>>
>>>Seems like the object owner should also change when the object moves
>>>from one container to another.
> 
> 
>>Consider a file which is opened in 2 processes. one of the processes
>>wants to move to another container then. How would you decide whether
>>to change the file owner or not?
>>
> 
> 
> If a process has sufficient rights to move a file to a new container
> then it should be okay to assign the file to the new container.  
there is no such notion as  "rights to move a file to a new container".
The same file can be opened in processes belonging to other containers.
And you have no any clue whether to have to change the owner or not.

> Though the point is, if a resource (like file) is getting migrated to a
> new container then all the attributes (like owner, #pages in memory
> etc.) attached to that resource (file) should also migrate to this new
> container.  Otherwise the semantics of where does the resource belong
> becomes very difficult.
The same for many other resources. It is a big mistake thinking that most resources
belong to the processes and the owner process can be easily determined.

> And if you really want a resource to not be able to migrate from one
> container then we could define IMMUTABLE flag to indicate that behavior.
I hope not that one used in ext[23]? :)

Kirill