Re: [PATCH 1/2] scalable rw_mutex

[Andrew Morton]

On Fri, 11 May 2007 10:07:17 -0700 (PDT)
Christoph Lameter <clameter@xxxxxxx> wrote:

> On Fri, 11 May 2007, Andrew Morton wrote:
> 
> > yipes.  percpu_counter_sum() is expensive.
> 
> Capable of triggering NMI watchdog on 4096+ processors?

Well.  That would be a millisecond per cpu which sounds improbable.  And
we'd need to be calling it under local_irq_save() which we presently don't.
And nobody has reported any problems against the existing callsites.

But it's no speed demon, that's for sure.
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