Hi Nick, On Tue, Mar 14, 2017 at 07:23:43PM +1000, Nicholas Piggin wrote: > The POWER8 idle code has a neat trick of programming the power on engine > to restore a low bit into HSPRG0, so idle wakeup code can test and see > if it has been programmed this way and therefore lost all state, and > avoiding the expensive full restore if not. > > However this messes with our r13 PACA pointer, and requires HSPRG0 to > be written to throughout the exception handlers and idle wakeup, rather > than just once on kernel entry. > > Remove this complexity and assume winkle sleeps always require a state > restore. This speedup is later re-introduced by counting per-core winkles > and setting a bitmap of threads with state loss when all are in winkle. >
Looks good to me. > Signed-off-by: Nicholas Piggin <npig...@gmail.com> Reviewed-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com> -- Thanks and Regards gautham.
