[PATCH] powerpc: Fix bogus cache flushing on all 40x and BookE processors v2

Benjamin Herrenschmidt benh at kernel.crashing.org
Fri Dec 5 09:02:49 EST 2008


On Thu, 2008-12-04 at 07:33 -0500, Josh Boyer wrote:
> On Thu, 04 Dec 2008 17:12:59 +1100
> Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:
> 
> > We were missing the CPU_FTR_NOEXECUTE bit in our cputable for all
> > these processors. The result is that update_mmu_cache() would flush
> > the cache for all pages mapped to userspace which is totally
> > unnecessary on those processors since we already handle flushing
> > on execute in the page fault path.
> > 
> > This should provide a nice speed up ;-)
> 
> Did you test it this time?  If so, how and what were the results?

Yes, I verified I no longer had PG_arch1 all over my PCI GART pages with
DRI enabled :-)

I didn't actually benchmark anything.

Cheers,
Ben.




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