Hi Steve, On 09/11/2018 12:50, Steve Sistare wrote: > Move the update of idle_stamp from idle_balance to the call site in > pick_next_task_fair, to prepare for a future patch that adds work to > pick_next_task_fair which must be included in the idle_stamp interval. > No functional change. > > Signed-off-by: Steve Sistare <steven.sist...@oracle.com> > --- > kernel/sched/fair.c | 23 ++++++++++++++--------- > 1 file changed, 14 insertions(+), 9 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 9031d39..da368ed 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3725,6 +3725,8 @@ static inline void update_misfit_status(struct > task_struct *p, struct rq *rq) > rq->misfit_task_load = task_h_load(p); > } > > +#define IF_SMP(statement) statement > +
I'm not too hot on those IF_SMP() macros. Since you're not introducing any other user for them, what about an inline function for rq->idle_stamp setting ? When it's mapped to an empty statement (!CONFIG_SMP) GCC is smart enough to remove the rq_clock() that would be passed to it on CONFIG_SMP: ----->8----- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c11adf3..34d9864 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3725,7 +3725,10 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq) rq->misfit_task_load = task_h_load(p); } -#define IF_SMP(statement) statement +static inline void set_rq_idle_stamp(struct rq *rq, u64 value) +{ + rq->idle_stamp = value; +} static void overload_clear(struct rq *rq) { @@ -3772,7 +3775,7 @@ static inline int idle_balance(struct rq *rq, struct rq_flags *rf) return 0; } -#define IF_SMP(statement) /* empty */ +static inline void set_rq_idle_stamp(struct rq *rq, u64 value) {} static inline void overload_clear(struct rq *rq) {} static inline void overload_set(struct rq *rq) {} @@ -6773,12 +6776,12 @@ done: __maybe_unused; * We must set idle_stamp _before_ calling idle_balance(), such that we * measure the duration of idle_balance() as idle time. */ - IF_SMP(rq->idle_stamp = rq_clock(rq);) + set_rq_idle_stamp(rq, rq_clock(rq)); new_tasks = idle_balance(rq, rf); if (new_tasks) - IF_SMP(rq->idle_stamp = 0;) + set_rq_idle_stamp(rq, 0); /* * Because idle_balance() releases (and re-acquires) rq->lock, it is