[PATCH 1/2] evl/sched: Add sched_out handler to sched_class

From: Jan Kiszka <[email protected]>

This shall be invoked before a thread switch, providing both the current
and the next thread as arguments. Some scheduling classes may need it to
correctly handle their state as the sched_pick may not be invoked when a
higher-weighted class is providing the next thread.

Signed-off-by: Jan Kiszka <[email protected]>
---
 include/evl/sched.h     | 2 ++
 kernel/evl/sched/core.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/include/evl/sched.h b/include/evl/sched.h
index ae9690860146c..0b16f1b1cf626 100644
--- a/include/evl/sched.h
+++ b/include/evl/sched.h
@@ -120,6 +120,8 @@ struct evl_sched_class {
 	void (*sched_dequeue)(struct evl_thread *thread);
 	void (*sched_requeue)(struct evl_thread *thread);
 	struct evl_thread *(*sched_pick)(struct evl_rq *rq);
+	void (*sched_out)(struct evl_thread *thread,
+			  struct evl_thread *next);
 	void (*sched_yield)(struct evl_thread *thread);
 	void (*sched_migrate)(struct evl_thread *thread,
 			      struct evl_rq *rq);
diff --git a/kernel/evl/sched/core.c b/kernel/evl/sched/core.c
index eb133e334d30f..0d49fc16bd67e 100644
--- a/kernel/evl/sched/core.c
+++ b/kernel/evl/sched/core.c
@@ -910,6 +910,7 @@ static __always_inline bool test_resched(struct evl_rq *this_rq)
  */
 void __evl_schedule(void) /* oob or/and hard irqs off (CPU migration-safe) */
 {
+	struct evl_sched_class *prev_schedclass;
 	struct evl_rq *this_rq = this_evl_rq();
 	struct evl_thread *prev, *next, *curr;
 	bool leaving_inband, inband_tail;
@@ -990,6 +991,10 @@ void __evl_schedule(void) /* oob or/and hard irqs off (CPU migration-safe) */
 	this_rq->curr = next;
 	leaving_inband = false;
 
+	prev_schedclass = prev->sched_class;
+	if (prev_schedclass->sched_out)
+		prev_schedclass->sched_out(prev, next);
+
 	/*
 	 * Careful: we _must_ have updated this_rq->curr before
 	 * performing the rest of the context switch code
-- 
2.47.3