On Fri, Jul 12, 2002 at 12:10:41AM -0700, Alfred Perlstein wrote:
> * Julian Elischer <[EMAIL PROTECTED]> [020712 00:00] wrote:
> >
> >
> > On Thu, 11 Jul 2002, Alfred Perlstein wrote:
> > >
> > > That's true, but could someone explain how one can safely and
> > > effeciently manipulate such a structure in an SMP environment?
> >
> > what does NetBSD do for that?
>
> They don't!
>
> *** waves skull staff exasperatedly ***
>
> RORWLRLRLLRL
Again, Alfred is right. :-)
I can't think of a way to ensure that the owner of the other mbuf
doesn't manipulate its two forward/backward pointers while we're
manipulating ours. The only way that springs to mind is to have them
protected by a mutex, but:
1) that would be very expensive and would bloat the mbuf structure a
LOT;
2) we would probably run into lock order reversal problems.
I see now what Alfred meant when he made his original comment.
--
Bosko Milekic
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