Re: [patch 04/15] Generic Mutex Subsystem, add-atomic-call-func-x86_64.patch

[Nicolas Pitre <nico@cam.org>]

On Wed, 21 Dec 2005, Nick Piggin wrote:

> Nicolas Pitre wrote:
> > On Tue, 20 Dec 2005, Nick Piggin wrote:
> 
> > > Considering that on UP, the arm should not need to disable interrupts
> > > for this function (or has someone refuted Linus?), how about:
> > 
> > 
> > Kernel preemption.
> > 
> 
> preempt_disable() ?

Sure, and we're now more costly than the current implementation with irq 
disabling.

If we go with simple mutexes that's because there is a gain, even a huge 
one on ARM, especially for the fast uncontended case.  If you guys 
insist on making things so generic and rigid then there is no gain 
anymore worth the bother.


Nicolas
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