[PATCH 03/16] sched: add sched_class->task_dead.

[Juri Lelli <juri.lelli@gmail.com>]

From: Dario Faggioli <raistlin@linux.it>

Add a new function to the scheduling class interface. It is called
at the end of a context switch, if the prev task is in TASK_DEAD state.

It might be useful for the scheduling classes that want to be notified
when one of their task dies, e.g. to perform some cleanup actions.

Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
---
 include/linux/sched.h |    1 +
 kernel/sched/core.c   |    3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0dd42a0..c8955a2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1077,6 +1077,7 @@ struct sched_class {
 	void (*set_curr_task) (struct rq *rq);
 	void (*task_tick) (struct rq *rq, struct task_struct *p, int queued);
 	void (*task_fork) (struct task_struct *p);
+	void (*task_dead) (struct task_struct *p);
 
 	void (*switched_from) (struct rq *this_rq, struct task_struct *task);
 	void (*switched_to) (struct rq *this_rq, struct task_struct *task);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d8927f..fc0f7d8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1774,6 +1774,9 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
 	if (mm)
 		mmdrop(mm);
 	if (unlikely(prev_state == TASK_DEAD)) {
+		if (prev->sched_class->task_dead)
+			prev->sched_class->task_dead(prev);
+
 		/*
 		 * Remove function-return probe instances associated with this
 		 * task and put them back on the free list.
-- 
1.7.9.5