Invert sense of SLB class bit

Sonny Rao sonny at
Wed Sep 7 07:03:22 EST 2005

On Tue, Sep 06, 2005 at 02:59:47PM +1000, David Gibson wrote:
> Currently, we set the class bit in kernel SLB entries, and clear it on
> user SLB entries.  On POWER5, ERAT entries created in real mode have
> the class bit clear.  So to avoid flushing kernel ERAT entries on each
> context switch, this patch inverts our usage of the class bit, setting
> it on user SLB entries and clearing it on kernel SLB entries.
> Booted on POWER5 and G5.

Hmm, do you think it is worth doing an SDET (or something ) comparison
w/ and w/out this patch? 


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