On Monday, April 18, 2016 01:51:24 PM Wanpeng Li wrote: > Sometimes update_curr() is called w/o tasks actually running, it is > captured by: > u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; > We should not trigger cpufreq update in this case for rt/deadline > classes, and this patch fix it. > > Signed-off-by: Wanpeng Li <[email protected]>
The signed-off-by tag should agree with the From: header. One way to achieve that is to add an extra From: line at the start of the changelog. That said, this looks like a good catch that should go into 4.6 to me. Peter, what do you think? > --- > kernel/sched/deadline.c | 8 ++++---- > kernel/sched/rt.c | 8 ++++---- > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index affd97e..8f9b5af 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -717,10 +717,6 @@ static void update_curr_dl(struct rq *rq) > if (!dl_task(curr) || !on_dl_rq(dl_se)) > return; > > - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ > - if (cpu_of(rq) == smp_processor_id()) > - cpufreq_trigger_update(rq_clock(rq)); > - > /* > * Consumed budget is computed considering the time as > * observed by schedulable tasks (excluding time spent > @@ -736,6 +732,10 @@ static void update_curr_dl(struct rq *rq) > return; > } > > + /* kick cpufreq (see the comment in linux/cpufreq.h). */ > + if (cpu_of(rq) == smp_processor_id()) > + cpufreq_trigger_update(rq_clock(rq)); > + > schedstat_set(curr->se.statistics.exec_max, > max(curr->se.statistics.exec_max, delta_exec)); > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index c41ea7a..19e1306 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -953,14 +953,14 @@ static void update_curr_rt(struct rq *rq) > if (curr->sched_class != &rt_sched_class) > return; > > - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ > - if (cpu_of(rq) == smp_processor_id()) > - cpufreq_trigger_update(rq_clock(rq)); > - > delta_exec = rq_clock_task(rq) - curr->se.exec_start; > if (unlikely((s64)delta_exec <= 0)) > return; > > + /* Kick cpufreq (see the comment in linux/cpufreq.h). */ > + if (cpu_of(rq) == smp_processor_id()) > + cpufreq_trigger_update(rq_clock(rq)); > + > schedstat_set(curr->se.statistics.exec_max, > max(curr->se.statistics.exec_max, delta_exec)); > >
