Commit d0ea0268 authored by Dongsheng Yang's avatar Dongsheng Yang Committed by Ingo Molnar
Browse files

sched: Implement task_nice() as static inline function 



As patch "sched: Move the priority specific bits into a new header file" exposes
the priority related macros in linux/sched/prio.h, we don't have to implement
task_nice() in kernel/sched/core.c any more.

This patch implements it in linux/sched/sched.h as static inline function,
saving the kernel stack and enhancing performance a bit.

Signed-off-by: default avatarDongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: clark.williams@gmail.com
Cc: rostedt@goodmis.org
Cc: raistlin@linux.it
Cc: juri.lelli@gmail.com
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1390878045-7096-1-git-send-email-yangds.fnst@cn.fujitsu.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6b6350f1

include/linux/sched.h

+10 −1
Original line number Diff line number Diff line
@@ -2094,7 +2094,16 @@ static inline void sched_autogroup_exit(struct signal_struct *sig) { } 
extern bool yield_to(struct task_struct *p, bool preempt);

extern void set_user_nice(struct task_struct *p, long nice);

extern int task_prio(const struct task_struct *p);

extern int task_nice(const struct task_struct *p);

/**

 * task_nice - return the nice value of a given task.

 * @p: the task in question.

 *

 * Return: The nice value [ -20 ... 0 ... 19 ].

 */

static inline int task_nice(const struct task_struct *p)

{

	return PRIO_TO_NICE((p)->static_prio);

}

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);

include/linux/sched/prio.h

+0 −1
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 
 */

#define NICE_TO_PRIO(nice)	(MAX_RT_PRIO + (nice) + 20)

#define PRIO_TO_NICE(prio)	((prio) - MAX_RT_PRIO - 20)

#define TASK_NICE(p)		PRIO_TO_NICE((p)->static_prio)



/*

 * 'User priority' is the nice value converted to something we

kernel/sched/core.c

+7 −19
Original line number Diff line number Diff line
@@ -3000,7 +3000,7 @@ void set_user_nice(struct task_struct *p, long nice) 
	unsigned long flags;

	struct rq *rq;



	if (TASK_NICE(p) == nice || nice < -20 || nice > 19)

	if (task_nice(p) == nice || nice < -20 || nice > 19)

		return;

	/*

	 * We have to be careful, if called from sys_setpriority(),
@@ -3078,7 +3078,7 @@ SYSCALL_DEFINE1(nice, int, increment) 
	if (increment > 40)

		increment = 40;



	nice = TASK_NICE(current) + increment;

	nice = task_nice(current) + increment;

	if (nice < -20)

		nice = -20;

	if (nice > 19)
@@ -3110,18 +3110,6 @@ int task_prio(const struct task_struct *p) 
	return p->prio - MAX_RT_PRIO;

}



/**

 * task_nice - return the nice value of a given task.

 * @p: the task in question.

 *

 * Return: The nice value [ -20 ... 0 ... 19 ].

 */

int task_nice(const struct task_struct *p)

{

	return TASK_NICE(p);

}

EXPORT_SYMBOL(task_nice);



/**

 * idle_cpu - is a given cpu idle currently?

 * @cpu: the processor in question.
@@ -3321,7 +3309,7 @@ recheck: 
	 */

	if (user && !capable(CAP_SYS_NICE)) {

		if (fair_policy(policy)) {

			if (attr->sched_nice < TASK_NICE(p) &&

			if (attr->sched_nice < task_nice(p) &&

			    !can_nice(p, attr->sched_nice))

				return -EPERM;

		}
@@ -3345,7 +3333,7 @@ recheck: 
		 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.

		 */

		if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {

			if (!can_nice(p, TASK_NICE(p)))

			if (!can_nice(p, task_nice(p)))

				return -EPERM;

		}
@@ -3385,7 +3373,7 @@ recheck: 
	 * If not changing anything there's no need to proceed further:

	 */

	if (unlikely(policy == p->policy)) {

		if (fair_policy(policy) && attr->sched_nice != TASK_NICE(p))

		if (fair_policy(policy) && attr->sched_nice != task_nice(p))

			goto change;

		if (rt_policy(policy) && attr->sched_priority != p->rt_priority)

			goto change;
@@ -3837,7 +3825,7 @@ SYSCALL_DEFINE3(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 
	else if (task_has_rt_policy(p))

		attr.sched_priority = p->rt_priority;

	else

		attr.sched_nice = TASK_NICE(p);

		attr.sched_nice = task_nice(p);



	rcu_read_unlock();
@@ -7010,7 +6998,7 @@ void normalize_rt_tasks(void) 
			 * Renice negative nice level userspace

			 * tasks back to 0:

			 */

			if (TASK_NICE(p) < 0 && p->mm)

			if (task_nice(p) < 0 && p->mm)

				set_user_nice(p, 0);

			continue;

		}

kernel/sched/cputime.c

+2 −2
Original line number Diff line number Diff line
@@ -142,7 +142,7 @@ void account_user_time(struct task_struct *p, cputime_t cputime, 
	p->utimescaled += cputime_scaled;

	account_group_user_time(p, cputime);



	index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;

	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;



	/* Add user time to cpustat. */

	task_group_account_field(p, index, (__force u64) cputime);
@@ -169,7 +169,7 @@ static void account_guest_time(struct task_struct *p, cputime_t cputime, 
	p->gtime += cputime;



	/* Add guest time to cpustat. */

	if (TASK_NICE(p) > 0) {

	if (task_nice(p) > 0) {

		cpustat[CPUTIME_NICE] += (__force u64) cputime;

		cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;

	} else {

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