On Tue, Mar 10, 2026 at 08:58:11PM +0530, Shrikanth Hegde wrote: > snooze_loop is done often in any system which has fair bit of > idle time. So it qualifies for even micro-optimizations. > > When breaking the snooze due to timeout, TIF_POLLING_NRFLAG is cleared > twice. Clearing the bit invokes atomics. Avoid double clear and thereby > avoid one atomic write. > > dev->poll_time_limit indicates whether the loop was broken due to > timeout. Use that instead of defining a new variable. > > Signed-off-by: Shrikanth Hegde <[email protected]> > --- > drivers/cpuidle/cpuidle-powernv.c | 5 ++++- > drivers/cpuidle/cpuidle-pseries.c | 5 ++++- > 2 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle-powernv.c > b/drivers/cpuidle/cpuidle-powernv.c > index 9ebedd972df0..b89e7111e7b8 100644 > --- a/drivers/cpuidle/cpuidle-powernv.c > +++ b/drivers/cpuidle/cpuidle-powernv.c > @@ -95,7 +95,10 @@ static int snooze_loop(struct cpuidle_device *dev, > > HMT_medium(); > ppc64_runlatch_on(); > - clear_thread_flag(TIF_POLLING_NRFLAG); > + > + /* Avoid double clear when breaking */ > + if (!dev->poll_time_limit) > + clear_thread_flag(TIF_POLLING_NRFLAG); > > local_irq_disable(); > > diff --git a/drivers/cpuidle/cpuidle-pseries.c > b/drivers/cpuidle/cpuidle-pseries.c > index f68c65f1d023..864dd5d6e627 100644 > --- a/drivers/cpuidle/cpuidle-pseries.c > +++ b/drivers/cpuidle/cpuidle-pseries.c > @@ -64,7 +64,10 @@ int snooze_loop(struct cpuidle_device *dev, struct > cpuidle_driver *drv, > } > > HMT_medium(); > - clear_thread_flag(TIF_POLLING_NRFLAG); > + > + /* Avoid double clear when breaking */ > + if (!dev->poll_time_limit) > + clear_thread_flag(TIF_POLLING_NRFLAG); > > raw_local_irq_disable(); > > -- > 2.43.0 > >
LGTM Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <[email protected]>
