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Subject: Re: What was the problem with quicklists and x86-64?
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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To: Christoph Lameter <clameter@sgi.com>
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Date: Fri, 14 Dec 2007 09:27:39 +1100
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On Thu, 2007-12-13 at 13:33 -0800, Christoph Lameter wrote:
> > 
> > Ah ok, so that's a NUMA issue due to how the quicklists are
> implemented,
> > I see. Note that the flush isn't necessary a solution on all
> platforms.
> > On powerpc, I -still- need to defer with RCU as we don't do anything
> in
> > flush tlb. Our TLB invalidations are HW broadcast in the first
> place,
> > but what we need to sync with is the SW hash reload code.
> > 
> > So your solution in the quicklists doesn't solve the problem for us.
> 
> No this may mean that the problem does not exist on powerpc since it 
> seems to be okay to free pages before all processors have flushed the 
> TLBs? Or are you deferrring the freeing of the pages via RCU?

I'm deferring the freeing with RCU.

Ben.