[no subject]

From: Henrik Austad
Date: Mon Apr 20 2009 - 09:54:44 EST


LKML <linux-kernel@xxxxxxxxxxxxxxx>, Peter Ziljstra <peterz@xxxxxxxxxxxxx>, Henrik Austad <henrik@xxxxxxxxx>
Subject: [PATCH 1/2] sched: Move priority calculation into sched_class.
Date: Mon, 20 Apr 2009 15:55:52 +0200
Message-Id: <1240235753-1180-1-git-send-email-henrik@xxxxxxxxx>
X-Mailer: git-send-email 1.6.1.2

When calculating the normal priority of a task, sched.c tested to see if the
task was an RT-task, or other. By moving this into sched_class, the calculation
becomes more modular, and the core scheduler becomes less aware of sched-class'
internals.

Signed-off-by: Henrik Austad <henrik@xxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
include/linux/sched.h | 1 +
kernel/sched.c | 16 +---------------
kernel/sched_fair.c | 7 +++++++
kernel/sched_idletask.c | 6 ++++++
kernel/sched_rt.c | 6 ++++++
5 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b4c38bc..f16db27 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1018,6 +1018,7 @@ struct sched_class {
int running);
void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
int oldprio, int running);
+ int (*normal_prio) (struct task_struct *task);

#ifdef CONFIG_FAIR_GROUP_SCHED
void (*moved_group) (struct task_struct *p);
diff --git a/kernel/sched.c b/kernel/sched.c
index b902e58..d78c84e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1806,14 +1806,6 @@ static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
}

/*
- * __normal_prio - return the priority that is based on the static prio
- */
-static inline int __normal_prio(struct task_struct *p)
-{
- return p->static_prio;
-}
-
-/*
* Calculate the expected normal priority: i.e. priority
* without taking RT-inheritance into account. Might be
* boosted by interactivity modifiers. Changes upon fork,
@@ -1822,13 +1814,7 @@ static inline int __normal_prio(struct task_struct *p)
*/
static inline int normal_prio(struct task_struct *p)
{
- int prio;
-
- if (task_has_rt_policy(p))
- prio = MAX_RT_PRIO-1 - p->rt_priority;
- else
- prio = __normal_prio(p);
- return prio;
+ return p->sched_class->normal_prio(p);
}

/*
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3816f21..c94519a 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1749,6 +1749,12 @@ static void prio_changed_fair(struct rq *rq, struct task_struct *p,
check_preempt_curr(rq, p, 0);
}

+/* Return the expected, normal priority */
+static int normal_prio_fair(struct task_struct *p)
+{
+ return p->static_prio;
+}
+
/*
* We switched to the sched_fair class.
*/
@@ -1815,6 +1821,7 @@ static const struct sched_class fair_sched_class = {
.task_new = task_new_fair,

.prio_changed = prio_changed_fair,
+ .normal_prio = normal_prio_fair,
.switched_to = switched_to_fair,

#ifdef CONFIG_FAIR_GROUP_SCHED
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c
index 8a21a2e..e52ae7c 100644
--- a/kernel/sched_idletask.c
+++ b/kernel/sched_idletask.c
@@ -96,6 +96,11 @@ static void prio_changed_idle(struct rq *rq, struct task_struct *p,
check_preempt_curr(rq, p, 0);
}

+static int normal_prio_idle(struct task_struct *p)
+{
+ return p->static_prio;
+}
+
/*
* Simple, special scheduling class for the per-CPU idle tasks:
*/
@@ -122,6 +127,7 @@ static const struct sched_class idle_sched_class = {
.task_tick = task_tick_idle,

.prio_changed = prio_changed_idle,
+ .normal_prio = normal_prio_idle,
.switched_to = switched_to_idle,

/* no .task_new for idle tasks */
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index f2c66f8..5c9a8f1 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1664,6 +1664,11 @@ static void prio_changed_rt(struct rq *rq, struct task_struct *p,
}
}

+static int normal_prio_rt(struct task_struct *p)
+{
+ return MAX_RT_PRIO-1 - p->rt_priority;
+}
+
static void watchdog(struct rq *rq, struct task_struct *p)
{
unsigned long soft, hard;
@@ -1752,6 +1757,7 @@ static const struct sched_class rt_sched_class = {
.task_tick = task_tick_rt,

.prio_changed = prio_changed_rt,
+ .normal_prio = normal_prio_rt,
.switched_to = switched_to_rt,
};

--
1.6.1.2

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