Hi Nick, On Tue, Mar 14, 2017 at 07:23:48PM +1000, Nicholas Piggin wrote: > When taking the core idle state lock, grab it immediately like a > regular lock, rather than adding more tests in there. Holding the lock > keeps it stable, so there is no need to do it whole holding the > reservation.
I agree with this patch. Just a minor query > > Signed-off-by: Nicholas Piggin <npig...@gmail.com> > --- > arch/powerpc/kernel/idle_book3s.S | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) > > diff --git a/arch/powerpc/kernel/idle_book3s.S > b/arch/powerpc/kernel/idle_book3s.S > index 1c91dc35c559..3cb75907c5c5 100644 > --- a/arch/powerpc/kernel/idle_book3s.S > +++ b/arch/powerpc/kernel/idle_book3s.S > @@ -488,12 +488,12 @@ BEGIN_FTR_SECTION > CHECK_HMI_INTERRUPT > END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) > > - lbz r7,PACA_THREAD_MASK(r13) > ld r14,PACA_CORE_IDLE_STATE_PTR(r13) > -lwarx_loop2: > - lwarx r15,0,r14 > - andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h > + lbz r7,PACA_THREAD_MASK(r13) Is reversing the order of loads into r7 and r14 intentional? Other than that, Reviewed-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com> > + > /* > + * Take the core lock to synchronize against other threads. > + * > * Lock bit is set in one of the 2 cases- > * a. In the sleep/winkle enter path, the last thread is executing > * fastsleep workaround code. > @@ -501,7 +501,14 @@ lwarx_loop2: > * workaround undo code or resyncing timebase or restoring context > * In either case loop until the lock bit is cleared. > */ > +1: > + lwarx r15,0,r14 > + andis. r9,r15,PNV_CORE_IDLE_LOCK_BIT@h > bnel- core_idle_lock_held > + oris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h > + stwcx. r15,0,r14 > + bne- 1b > + isync > > andi. r9,r15,PNV_CORE_IDLE_THREAD_BITS > cmpwi cr2,r9,0 > @@ -513,11 +520,6 @@ lwarx_loop2: > * cr4 - gt or eq if waking up from complete hypervisor state loss. > */ > > - oris r15,r15,PNV_CORE_IDLE_LOCK_BIT@h > - stwcx. r15,0,r14 > - bne- lwarx_loop2 > - isync > - > BEGIN_FTR_SECTION > lbz r4,PACA_SUBCORE_SIBLING_MASK(r13) > and r4,r4,r15 > -- > 2.11.0 >
