In message <[EMAIL PROTECTED]>, Matt Dillon writes:
> Actually, all this talk does imply that VM objects should be independant
> of vnodes. Devices may need to mmap (requiring a VM object), but
> don't need all the baggage of a vnode. Julian is absolutely correct
> there.
Well, you have other VM Objects which doesn't map to vnodes: swap
backed anonymous objects for instance.
> We do need to guarentee locking order, which means that all I/O
> operations should be consistent. If a device or vnode is mmap()able,
> then all read, write, and truncation(/extention) ops *should* run
> through the VM object first:
We guarantee that today my mapping the actual hardware and my having
all read/writes be synchronouse. I remember at least one other
UNIX which didn't make that guarantee.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-hackers" in the body of the message
