At Thu, 23 Aug 2007 13:54:56 +0200, Marcus Brinkmann wrote: > > If so, it seems that if I want status bits for the pages that the > > resource manager maps to its clients, then I have to be careful to > > only map pages of the same size as the ones the manager has. I > > imagine that I can request new mappings from sigma0 as appropriate, > > Or insert an intermediate task.
This occured to me as well but my intuition suggests that the costs are strictly greater than only have small mappings: now you have the superpage mappings plus the small mappings and the overhead of additional tasks. > > but this basically defeats the advantage of having mapped the > > superpages to begin with--most mappings will be small and thus the > > address space with quickly be filled with small mappings. Plus, with > > this approach, there is the overhead of the cost of the unmap and > > re-map operations. > > Yes. However, there is a related problem that you can not unmap > selectively. I vaguely remember that Espen had a selective unmap > proposal at some time as a small modification to the L4 X.2 interface. > But I don't remember any details. Whatever that proposal was should > also provide an opportunity to do selective status bit checking, > shouldn't it? I think the problem was that the space had to be identified, however, as the original recipient can grant the mapping meaning that the mapping now exists in a different space, many complications ensue. Thanks, Neal _______________________________________________ L4-hurd mailing list [email protected] http://lists.gnu.org/mailman/listinfo/l4-hurd
