GSN-EDF: avoid double lock acquisition in FMLP

Extra lock acquisition causes unnecessary overhead.

1 files changed, 4 insertions, 12 deletions

diff --git a/litmus/sched_gsn_edf.c b/litmus/sched_gsn_edf.c
index 9e3eb22eed74..26014437cc3e 100644
--- a/litmus/sched_gsn_edf.c
+++ b/litmus/sched_gsn_edf.c
@@ -697,14 +697,6 @@ static void __clear_priority_inheritance(struct task_struct* t)
         gsnedf_job_arrival(t);
 }
 
-/* called with IRQs off */
-static void clear_priority_inheritance(struct task_struct* t)
-{
-        raw_spin_lock(&gsnedf_lock);
-        __clear_priority_inheritance(t);
-        raw_spin_unlock(&gsnedf_lock);
-}
-
 /* set and clear at the same time to avoid having to
  * acquire the runqueue lock twice */
 static void update_priority_inheritance(
@@ -827,7 +819,7 @@ int gsnedf_fmlp_lock(struct litmus_lock* l)
 
 int gsnedf_fmlp_unlock(struct litmus_lock* l)
 {
-        struct task_struct *t = current, *next;
+        struct task_struct *t = current, *next, *blocked = NULL;
         struct fmlp_semaphore *sem = fmlp_from_lock(l);
         unsigned long flags;
         int err = 0;
@@ -862,7 +854,7 @@ int gsnedf_fmlp_unlock(struct litmus_lock* l)
                         /* Well, if next is not the highest-priority waiter,
                          * then it ought to inherit the highest-priority
                          * waiter's priority. */
-                        set_priority_inheritance(next, sem->hp_waiter);
+                        blocked = sem->hp_waiter;
                 }
 
                 /* wake up next */
@@ -872,8 +864,8 @@ int gsnedf_fmlp_unlock(struct litmus_lock* l)
                 sem->owner = NULL;
 
         /* we lose the benefit of priority inheritance (if any) */
-        if (tsk_rt(t)->inh_task)
-                clear_priority_inheritance(t);
+        if (tsk_rt(t)->inh_task || blocked)
+                update_priority_inheritance(t, next, blocked);
 
 out:
         spin_unlock_irqrestore(&sem->wait.lock, flags);