Re: [rp] Userspace RCU 0.2.3

From: Mathieu Desnoyers
Date: Sun Oct 18 2009 - 18:02:52 EST


* Pavel Machek (pavel@xxxxxx) wrote:
> On Thu 2009-10-15 13:40:54, Pierre-Marc Fournier wrote:
> > Josh Triplett wrote:
> > >
> > > Even Debian has given up on real 386 systems at this point, primarily
> > > because system libraries like glibc have; 486 and better represents the
> > > bare minimum required at this point. I don't know of any distributions
> > > supporting real 386 systems at this point, and doing so would represent
> > > a major undertaking.
> > >
> >
> > What about embedded systems? Anyone know if some 386 chips, perhaps even
> > in smp configurations, are still in use in those?
>
> smp 386: definitely not.

Hrm, so for UP 386, I wonder what's the best approach.

One would be to encapsulate all write accesses to the RCU pointers. If
we detect that the architecture lacks cmpxchg, _all_ update operations
(rcu_assign_pointer, rcu_xchg_pointer and rcu_cmpxchg_pointer) would
have to use the signal-disabled+mutex fall-back.

Does it make sense ?

Mathieu

>
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Mathieu Desnoyers
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