Add scheduler API sched_relinquish(), the API is used to implement

yield() and sched_yield() syscalls. Every scheduler has its own way
to relinquish cpu, the ULE and CORE schedulers have two internal run-
queues, a timesharing thread which calls yield() syscall should be
moved to inactive queue.

6 files changed, 46 insertions, 6 deletions

diff --git a/sys/kern/ksched.c b/sys/kern/ksched.c
index c4a5f0b..7884d90 100644
--- a/sys/kern/ksched.c
+++ b/sys/kern/ksched.c
@@ -253,9 +253,7 @@ ksched_getscheduler(register_t *ret, struct ksched *ksched, struct thread *td)
 int
 ksched_yield(register_t *ret, struct ksched *ksched)
 {
-	mtx_lock_spin(&sched_lock);
-	curthread->td_flags |= TDF_NEEDRESCHED;
-	mtx_unlock_spin(&sched_lock);
+	sched_relinquish(curthread);
 	return 0;
 }
 
diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c
index 60f6df6..399c9e5 100644
--- a/sys/kern/sched_4bsd.c
+++ b/sys/kern/sched_4bsd.c
@@ -1354,6 +1354,19 @@ sched_is_bound(struct thread *td)
 	return (td->td_kse->ke_flags & KEF_BOUND);
 }
 
+void
+sched_relinquish(struct thread *td)
+{
+	struct ksegrp *kg;
+
+	kg = td->td_ksegrp;
+	mtx_lock_spin(&sched_lock);
+	if (kg->kg_pri_class == PRI_TIMESHARE)
+		sched_prio(td, PRI_MAX_TIMESHARE);
+	mi_switch(SW_VOL, NULL);
+	mtx_unlock_spin(&sched_lock);
+}
+
 int
 sched_load(void)
 {
@@ -1365,11 +1378,13 @@ sched_sizeof_ksegrp(void)
 {
 	return (sizeof(struct ksegrp) + sizeof(struct kg_sched));
 }
+
 int
 sched_sizeof_proc(void)
 {
 	return (sizeof(struct proc));
 }
+
 int
 sched_sizeof_thread(void)
 {
diff --git a/sys/kern/sched_core.c b/sys/kern/sched_core.c
index 3f5554b..494e04f 100644
--- a/sys/kern/sched_core.c
+++ b/sys/kern/sched_core.c
@@ -2310,6 +2310,21 @@ sched_load(void)
 #endif
 }
 
+void
+sched_relinquish(struct thread *td)
+{
+	struct ksegrp *kg;
+
+	kg = td->td_ksegrp;
+	mtx_lock_spin(&sched_lock);
+	if (sched_is_timeshare(kg)) {
+		sched_prio(td, PRI_MAX_TIMESHARE);
+		td->td_kse->ke_flags |= KEF_NEXTRQ;
+	}
+	mi_switch(SW_VOL, NULL);
+	mtx_unlock_spin(&sched_lock);
+}
+
 int
 sched_sizeof_ksegrp(void)
 {
diff --git a/sys/kern/sched_ule.c b/sys/kern/sched_ule.c
index a3cccfe..a352445 100644
--- a/sys/kern/sched_ule.c
+++ b/sys/kern/sched_ule.c
@@ -1974,6 +1974,19 @@ sched_is_bound(struct thread *td)
 	return (td->td_kse->ke_flags & KEF_BOUND);
 }
 
+void
+sched_relinquish(struct thread *td)
+{
+	struct ksegrp *kg;
+
+	kg = td->td_ksegrp;
+	mtx_lock_spin(&sched_lock);
+	if (kg->kg_pri_class == PRI_TIMESHARE)
+		sched_prio(td, PRI_MAX_TIMESHARE);
+	mi_switch(SW_VOL, NULL);
+	mtx_unlock_spin(&sched_lock);
+}
+
 int
 sched_load(void)
 {
diff --git a/sys/posix4/ksched.c b/sys/posix4/ksched.c
index c4a5f0b..7884d90 100644
--- a/sys/posix4/ksched.c
+++ b/sys/posix4/ksched.c
@@ -253,9 +253,7 @@ ksched_getscheduler(register_t *ret, struct ksched *ksched, struct thread *td)
 int
 ksched_yield(register_t *ret, struct ksched *ksched)
 {
-	mtx_lock_spin(&sched_lock);
-	curthread->td_flags |= TDF_NEEDRESCHED;
-	mtx_unlock_spin(&sched_lock);
+	sched_relinquish(curthread);
 	return 0;
 }
 
diff --git a/sys/sys/sched.h b/sys/sys/sched.h
index 5c5825f..b782c1f 100644
--- a/sys/sys/sched.h
+++ b/sys/sys/sched.h
@@ -79,6 +79,7 @@ void	sched_add(struct thread *td, int flags);
 void	sched_clock(struct thread *td);
 void	sched_rem(struct thread *td);
 void	sched_tick(void);
+void	sched_relinquish(struct thread *td);
 
 /*
  * Binding makes cpu affinity permanent while pinning is used to temporarily