Re: [PATCH] - Improve SN2 TLB flushing algorithms

From: Christoph Hellwig <hch_at_infradead.org>
Date: 2004-01-30 00:40:38
On Wed, Jan 28, 2004 at 04:36:01PM -0600, Jack Steiner wrote:
> Are you suggesting that we remove the #ifdef OR hide the code
> in a function that, depending on config options, may or may not do anything?

Yes.  And I wonder whether we should just do it unconditionally, but
I'm not really sure.

> > > +		if (!cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
> > > +			cpu_set(smp_processor_id(), mm->cpu_vm_mask);
> > 
> > cpu_test_and_set()?
> 
> On IA64 (not sure about other architectures), cpu_test_and_set will always 
> set the bit regardless of it's previous state. That causes the cacheline containing
> the bitmask to be bounced between cpus - possibly unnecessarily. For most

Ok.

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Received on Thu Jan 29 08:41:09 2004

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