sched: make early bootup sched_clock() use safer (6892b75e) · Commits · 戴 / test

kernel/sched.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -668,6 +668,8 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32;
		*/
		unsigned int sysctl_sched_rt_period = 1000000;

		static __read_mostly int scheduler_running;

		/*
		* part of the period that we allow rt tasks to run in us.
		* default: 0.95s
		@@ -689,13 +691,15 @@ unsigned long long cpu_clock(int cpu)
		unsigned long flags;
		struct rq *rq;

		local_irq_save(flags);
		rq = cpu_rq(cpu);
		/*
		* Only call sched_clock() if the scheduler has already been
		* initialized (some code might call cpu_clock() very early):
		*/
		if (rq->idle)
		if (unlikely(!scheduler_running))
		return 0;

		local_irq_save(flags);
		rq = cpu_rq(cpu);
		update_rq_clock(rq);
		now = rq->clock;
		local_irq_restore(flags);
		@@ -7284,6 +7288,8 @@ void __init sched_init(void)
		* During early bootup we pretend to be a normal task:
		*/
		current->sched_class = &fair_sched_class;

		scheduler_running = 1;
		}

		#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP