Commit 1e0a2ba7 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

sched: Provide idle_rq() helper 



A fix for the dl_server 'requires' idle_cpu() usage, which made me
note that it and available_idle_cpu() are extern function calls.

And while idle_cpu() is used outside of kernel/sched/,
available_idle_cpu() is not.

This makes it hard to make idle_cpu() an inline helper, so provide
idle_rq() and implement idle_cpu() and available_idle_cpu() using
that.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
parent 64e6fa76

include/linux/sched.h

+0 −1
Original line number Diff line number Diff line
@@ -1874,7 +1874,6 @@ static inline int task_nice(const struct task_struct *p) 
extern int can_nice(const struct task_struct *p, const int nice);

extern int task_curr(const struct task_struct *p);

extern int idle_cpu(int cpu);

extern int available_idle_cpu(int cpu);

extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *);

extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *);

extern void sched_set_fifo(struct task_struct *p);

kernel/sched/sched.h

+22 −0
Original line number Diff line number Diff line
@@ -1364,6 +1364,28 @@ static inline u32 sched_rng(void) 
#define cpu_curr(cpu)		(cpu_rq(cpu)->curr)

#define raw_rq()		raw_cpu_ptr(&runqueues)



static inline bool idle_rq(struct rq *rq)

{

	return rq->curr == rq->idle && !rq->nr_running && !rq->ttwu_pending;

}



/**

 * available_idle_cpu - is a given CPU idle for enqueuing work.

 * @cpu: the CPU in question.

 *

 * Return: 1 if the CPU is currently idle. 0 otherwise.

 */

static inline bool available_idle_cpu(int cpu)

{

	if (!idle_rq(cpu_rq(cpu)))

		return 0;



	if (vcpu_is_preempted(cpu))

		return 0;



	return 1;

}



#ifdef CONFIG_SCHED_PROXY_EXEC

static inline void rq_set_donor(struct rq *rq, struct task_struct *t)

{

kernel/sched/syscalls.c

+1 −29
Original line number Diff line number Diff line
@@ -180,35 +180,7 @@ int task_prio(const struct task_struct *p) 
 */

int idle_cpu(int cpu)

{

	struct rq *rq = cpu_rq(cpu);



	if (rq->curr != rq->idle)

		return 0;



	if (rq->nr_running)

		return 0;



	if (rq->ttwu_pending)

		return 0;



	return 1;

}



/**

 * available_idle_cpu - is a given CPU idle for enqueuing work.

 * @cpu: the CPU in question.

 *

 * Return: 1 if the CPU is currently idle. 0 otherwise.

 */

int available_idle_cpu(int cpu)

{

	if (!idle_cpu(cpu))

		return 0;



	if (vcpu_is_preempted(cpu))

		return 0;



	return 1;

	return idle_rq(cpu_rq(cpu));

}



/**