On Wed, 25 Apr 2007 11:48:45 +1000 Paul Mackerras <paulus@xxxxxxxxx> wrote: > akpm@xxxxxxxxxxxxxxxxxxxx writes: > > > Avoid reevaluating smp_processor_id() > > > int this_cpu = smp_processor_id(); > > - unsigned long touch_timestamp = __get_cpu_var(touch_timestamp); > > + unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu); > > This is actually worse on those cpus that have a fast way to get to > the current cpu's per-cpu data. > The patch adds 4 bytes (strange number) to powerpc text and removes 32 from i386's. A net win, I guess. i386 now has a considerably better smp_processor_id(), but no special-case handling of per-cpu data. Maybe Jeremy has plans to move i386's per-cpu data into the pda also? - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
