a question about L4_MAP_ITEM_GRANT

Adam Lackorzynski adam at os.inf.tu-dresden.de
Thu Sep 13 23:59:23 CEST 2012


On Thu Sep 13, 2012 at 11:20:25 -0700, Chen Tian wrote:
> I have a simple question. If a parent maps a page into a child's space with
> this flag, can the parent regain this page and remove this mapping later? I

No, it can't, given it cannot name it anymore.

> did a simple test. It seems that with this flag in l4_task_map, the child
> owns the mapped page permanently. What I'd like to do is when a child
> finishes its job and returns such a granted page to its parent, the parent
> can reuse this page for some other child.

So why grant the page instead of just mapping it? So it's kept in the
parent and if the childs finishes, the parent can give it to another

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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