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

[Kirill Korotaev]

> > > > > 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

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