On Thu, May 15, 2014 at 03:59:20PM -0700, Ben Segall wrote: > task_hot checks exec_start on any runnable task, but if it has been > migrated since the it last ran, then exec_start is a clock_task from > another cpu. If the old cpu's clock_task was sufficiently far ahead of > this cpu's then the task will not be considered for another migration > until it has run. Instead reset exec_start whenever a task is migrated, > since it is presumably no longer hot anyway. > > Signed-off-by: Ben Segall <bseg...@google.com> > --- > kernel/sched/fair.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 28ccf50..9f8dfeb 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4544,6 +4544,9 @@ migrate_task_rq_fair(struct task_struct *p, int > next_cpu) > atomic_long_add(se->avg.load_avg_contrib, > &cfs_rq->removed_load); > } > + > + /* We have migrated, no longer consider this task hot */ > + se.exec_start = 0;
se->exec_start compiles loads better
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