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Subject: Re: [PATCH 1/3] High-res-timers part 1 (core) take 20
From: Robert Love <rml@tech9.net>
To: george anzinger <george@mvista.com>
Cc: Arjan van de Ven <arjanv@redhat.com>,
       Linus Torvalds <torvalds@transmeta.com>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Mon, 2002-12-09 at 02:03, george anzinger wrote:

> > > +     IF_SMP(if (old_base && (new_base != old_base))
> > > +            spin_unlock(&old_base->lock);
> > > +             )
> > 
> > Like here..... SMP dependent ifdef's of spinlock usage... shudder
> > 
> Well it does seem like a waste to do spinlock ordering code
> on a UP system...

Well the spin locks will compile away if !CONFIG_SMP, and then the
compiler will remove the empty branch.

But this is not just cleanliness: doesn't this evade the
preempt_disable() in the spin_unlock() on !CONFIG_SMP+CONFIG_PREEMPT?

	Robert Love

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