[PATCH 3/3] sched: Implement task_nice and task_prio as static inline functions.

From: Dongsheng Yang
Date: Mon Jan 27 2014 - 04:18:15 EST


As commit 0e0c0797 expose the priority related macros in linux/sched/prio.h,
we don't have to implement task_nice and task_prio in kernel/sched/core.c any
more.

This patch implement them in linux/sched/sched.h as static inline functions,
saving the kernel stack and enhancing the performance.

Signed-off-by: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx>
---
include/linux/sched.h | 26 ++++++++++++++++++++++++--
kernel/sched/core.c | 25 -------------------------
2 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index ba1b732..125145b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2082,8 +2082,30 @@ 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_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * Return: The priority value as seen by users in /proc.
+ * RT tasks are offset by -200. Normal tasks are centered
+ * around 0, value goes from -16 to +15.
+ */
+static inline 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 ].
+ */
+static inline int task_nice(const struct task_struct *p)
+{
+ return TASK_NICE(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);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7fea865..a8d6150 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3096,31 +3096,6 @@ SYSCALL_DEFINE1(nice, int, increment)
#endif

/**
- * task_prio - return the priority value of a given task.
- * @p: the task in question.
- *
- * Return: The priority value as seen by users in /proc.
- * RT tasks are offset by -200. Normal tasks are centered
- * around 0, value goes from -16 to +15.
- */
-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.
*
--
1.8.2.1

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