RE: On PATH_MAX

[Jonathan S. Shapiro]

On Tue, 2005-11-08 at 10:04 -0700, Christopher Nelson wrote:
> > On Tue, Nov 08, 2005 at 08:51:09AM -0700, Christopher Nelson wrote:
> > There is no transfer of data, there is only transfer of the 
> > container capability.  This capability gives access to a set 
> > of pages, which can be mapped in or out of the address space 
> > when the process likes.
> 
> You still have data transfer, even if it's only in the form of metadata.
> A thread can't access any memory until it's mapped into its address
> space.  If you say that a thread must only keep a handle to the metadata
> that defines the memory and then map it in and out as needed, you
> essentially turn the operation into an open..read..close, and you add
> tremendous complexity in the form of a buffering layer to map pages in
> and out.  I'm not saying its impossible, I'm saying its not a good idea,
> IMHO.

Actually, the metadata is shared, it isn't *nearly* as complex as
open/read/close, and it all works just fine in practice in a bunch of
current EROS subsystems.


shap