diff options
Diffstat (limited to 'kernel/sched/core.c')
| -rw-r--r-- | kernel/sched/core.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1deccd78be9..e85cda20ab2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2253,6 +2253,20 @@ unsigned long long task_sched_runtime(struct task_struct *p) struct rq *rq; u64 ns = 0; +#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) + /* + * 64-bit doesn't need locks to atomically read a 64bit value. + * So we have a optimization chance when the task's delta_exec is 0. + * Reading ->on_cpu is racy, but this is ok. + * + * If we race with it leaving cpu, we'll take a lock. So we're correct. + * If we race with it entering cpu, unaccounted time is 0. This is + * indistinguishable from the read occurring a few cycles earlier. + */ + if (!p->on_cpu) + return p->se.sum_exec_runtime; +#endif + rq = task_rq_lock(p, &flags); ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); task_rq_unlock(rq, p, &flags); @@ -2646,6 +2660,7 @@ asmlinkage void __sched notrace preempt_schedule(void) } while (need_resched()); } EXPORT_SYMBOL(preempt_schedule); +#endif /* CONFIG_PREEMPT */ /* * this is the entry point to schedule() from kernel preemption @@ -2679,8 +2694,6 @@ asmlinkage void __sched preempt_schedule_irq(void) exception_exit(prev_state); } -#endif /* CONFIG_PREEMPT */ - int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, void *key) { @@ -4748,7 +4761,7 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd) cpumask_clear_cpu(rq->cpu, old_rd->span); /* - * If we dont want to free the old_rt yet then + * If we dont want to free the old_rd yet then * set old_rd to NULL to skip the freeing later * in this function: */ @@ -4896,8 +4909,9 @@ static void update_top_cache_domain(int cpu) if (sd) { id = cpumask_first(sched_domain_span(sd)); size = cpumask_weight(sched_domain_span(sd)); - rcu_assign_pointer(per_cpu(sd_busy, cpu), sd->parent); + sd = sd->parent; /* sd_busy */ } + rcu_assign_pointer(per_cpu(sd_busy, cpu), sd); rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); per_cpu(sd_llc_size, cpu) = size; |