sched: Always provide p->on_cpu (3ca7a440) · Commits · 戴 / test

include/linux/sched.h

+1 −3

Original line number	Diff line number	Diff line
		@@ -1200,9 +1200,7 @@ struct task_struct {
		int lock_depth; /* BKL lock depth */

		#ifdef CONFIG_SMP
		#ifdef __ARCH_WANT_UNLOCKED_CTXSW
		int oncpu;
		#endif
		int on_cpu;
		#endif

		int prio, static_prio, normal_prio;

kernel/sched.c

+29 −17

Original line number	Diff line number	Diff line
		@@ -838,18 +838,39 @@ static inline int task_current(struct rq rq, struct task_struct p)
		return rq->curr == p;
		}

		#ifndef __ARCH_WANT_UNLOCKED_CTXSW
		static inline int task_running(struct rq rq, struct task_struct p)
		{
		#ifdef CONFIG_SMP
		return p->on_cpu;
		#else
		return task_current(rq, p);
		#endif
		}

		#ifndef __ARCH_WANT_UNLOCKED_CTXSW
		static inline void prepare_lock_switch(struct rq rq, struct task_struct next)
		{
		#ifdef CONFIG_SMP
		/*
		* We can optimise this out completely for !SMP, because the
		* SMP rebalancing from interrupt is the only thing that cares
		* here.
		*/
		next->on_cpu = 1;
		#endif
		}

		static inline void finish_lock_switch(struct rq rq, struct task_struct prev)
		{
		#ifdef CONFIG_SMP
		/*
		* After ->on_cpu is cleared, the task can be moved to a different CPU.
		* We must ensure this doesn't happen until the switch is completely
		* finished.
		*/
		smp_wmb();
		prev->on_cpu = 0;
		#endif
		#ifdef CONFIG_DEBUG_SPINLOCK
		/* this is a valid case when another task releases the spinlock */
		rq->lock.owner = current;
		@@ -865,15 +886,6 @@ static inline void finish_lock_switch(struct rq rq, struct task_struct prev)
		}

		#else /* __ARCH_WANT_UNLOCKED_CTXSW */
		static inline int task_running(struct rq rq, struct task_struct p)
		{
		#ifdef CONFIG_SMP
		return p->oncpu;
		#else
		return task_current(rq, p);
		#endif
		}

		static inline void prepare_lock_switch(struct rq rq, struct task_struct next)
		{
		#ifdef CONFIG_SMP
		@@ -882,7 +894,7 @@ static inline void prepare_lock_switch(struct rq rq, struct task_struct next)
		* SMP rebalancing from interrupt is the only thing that cares
		* here.
		*/
		next->oncpu = 1;
		next->on_cpu = 1;
		#endif
		#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
		raw_spin_unlock_irq(&rq->lock);
		@@ -895,12 +907,12 @@ static inline void finish_lock_switch(struct rq rq, struct task_struct prev)
		{
		#ifdef CONFIG_SMP
		/*
		* After ->oncpu is cleared, the task can be moved to a different CPU.
		* After ->on_cpu is cleared, the task can be moved to a different CPU.
		* We must ensure this doesn't happen until the switch is completely
		* finished.
		*/
		smp_wmb();
		prev->oncpu = 0;
		prev->on_cpu = 0;
		#endif
		#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
		local_irq_enable();
		@@ -2686,8 +2698,8 @@ void sched_fork(struct task_struct *p, int clone_flags)
		if (likely(sched_info_on()))
		memset(&p->sched_info, 0, sizeof(p->sched_info));
		#endif
		#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
		p->oncpu = 0;
		#if defined(CONFIG_SMP)
		p->on_cpu = 0;
		#endif
		#ifdef CONFIG_PREEMPT
		/* Want to start with kernel preemption disabled. */
		@@ -5776,8 +5788,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
		rcu_read_unlock();

		rq->curr = rq->idle = idle;
		#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
		idle->oncpu = 1;
		#if defined(CONFIG_SMP)
		idle->on_cpu = 1;
		#endif
		raw_spin_unlock_irqrestore(&rq->lock, flags);

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