DragonFly BSD
DragonFly kernel List (threaded) for 2003-07
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Re: Annoucning DragonFly BSD!

From: Peter da Silva <peter-dragonfly@xxxxxxxxxxx>
Date: Thu, 17 Jul 2003 16:38:20 -0500

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.

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