Re: Annoucning DragonFly BSD!

[Peter da Silva <peter-dragonfly@xxxxxxxxxxx>]

Matthew Dillon wrote:
>     Well, I don't expect expect messages to ever get 'big' per say, auxillary
>     data will still be passed with pointer references from user->kernel
>     though anything that goes deeper into the kernel will likely be converted
>     into an iovec-like array of VM Objects.

I assume that anything large (blocks of data being written, etc) will be 
passed by reference rather than as part of the message, and only be 
marshalled into some kind of structured object that needs to be copied 
when they're passed into a domain (like over a network, or even in some 
cases to a file system running in user mode) where accessing them 
through a reference would be expensive.

Yes, no?

That would also resolve non-uniform memory maps: you'd just pass the 
reference around in the message and copy it later. If it becomes 
necessary to use some analog of "MEMF_PUBLIC" for efficiency that could 
be hidden in the emulation layer... and it should be possible to manage 
access to this memory so there's no potential compromises, assuming you 
don't actually grant access to this address space for untrusted servers.