1 files changed, 40 insertions, 14 deletions

diff --git a/litmus/nvidia_info.c b/litmus/nvidia_info.c
index dda863009fee..ab62ca1b5b11 100644
--- a/litmus/nvidia_info.c
+++ b/litmus/nvidia_info.c
@@ -553,7 +553,10 @@ static int gpu_klmirqd_increase_priority(struct task_struct *klmirqd, struct tas
 {
         int retval = 0;
 
-        TRACE_CUR("Increasing priority of nv klmirqd: %s/%d.\n", klmirqd->comm, klmirqd->pid);
+        TRACE_CUR("Increasing priority of %s/%d to %s/%d.\n",
+                        klmirqd->comm, klmirqd->pid,
+                        (hp) ? hp->comm : "nil",
+                        (hp) ? hp->pid : -1);
 
         /* the klmirqd thread should never attempt to hold a litmus-level real-time
          * so nested support is not required */
@@ -566,7 +569,10 @@ static int gpu_klmirqd_decrease_priority(struct task_struct *klmirqd, struct tas
 {
         int retval = 0;
 
-        TRACE_CUR("Decreasing priority of nv klmirqd: %s/%d.\n", klmirqd->comm, klmirqd->pid);
+        TRACE_CUR("Decreasing priority of %s/%d to %s/%d.\n",
+                        klmirqd->comm, klmirqd->pid,
+                        (hp) ? hp->comm : "nil",
+                        (hp) ? hp->pid : -1);
 
         /* the klmirqd thread should never attempt to hold a litmus-level real-time
          * so nested support is not required */
@@ -617,9 +623,12 @@ long enable_gpu_owner(struct task_struct *t)
 
         if (hp == t) {
                 /* we're the new hp */
-                TRACE_CUR("%s/%d is new hp on GPU %d.\n", t->comm, t->pid, gpu);
+                TRACE_CUR("%s/%d (eff_prio = %s/%d) is new hp on GPU %d.\n",
+                                t->comm, t->pid,
+                                effective_priority(t)->comm, effective_priority(t)->pid,
+                                gpu);
 
-                retval = gpu_klmirqd_increase_priority(reg->thread, (tsk_rt(hp)->inh_task)? tsk_rt(hp)->inh_task : hp);
+                retval = gpu_klmirqd_increase_priority(reg->thread, effective_priority(t));
         }
 #endif
 
@@ -671,13 +680,15 @@ long disable_gpu_owner(struct task_struct *t)
         }
 
         if (hp == t && new_hp != t) {
-                struct task_struct *to_inh = NULL;
+                struct task_struct *to_inh = (new_hp) ? effective_priority(new_hp) : NULL;
 
-                TRACE_CUR("%s/%d is no longer hp on GPU %d.\n", t->comm, t->pid, gpu);
-
-                if (new_hp) {
-                        to_inh = (tsk_rt(new_hp)->inh_task) ? tsk_rt(new_hp)->inh_task : new_hp;
-                }
+                TRACE_CUR("%s/%d is no longer hp on GPU %d; new hp = %s/%d (eff_prio = %s/%d).\n",
+                                                t->comm, t->pid,
+                                                gpu,
+                                                (new_hp) ? new_hp->comm : "nil",
+                                                (new_hp) ? new_hp->pid : -1,
+                                                (to_inh) ? to_inh->comm : "nil",
+                                                (to_inh) ? to_inh->pid : -1);
 
                 retval = gpu_klmirqd_decrease_priority(reg->thread, to_inh);
         }
@@ -707,6 +718,10 @@ int gpu_owner_increase_priority(struct task_struct *t)
         struct task_struct *hp = NULL;
         struct task_struct *hp_eff = NULL;
 
+#ifdef CONFIG_LITMUS_SOFTIRQD
+        int increase_klmirqd = 0;
+#endif
+
         BUG_ON(!is_realtime(t));
         BUG_ON(!tsk_rt(t)->held_gpus);
 
@@ -728,14 +743,24 @@ int gpu_owner_increase_priority(struct task_struct *t)
         if (hp != t) { /* our position in the heap may have changed. hp is already at the root. */
                 binheap_decrease(&tsk_rt(t)->gpu_owner_node, &reg->owners);
         }
-
 #ifdef CONFIG_LITMUS_SOFTIRQD
+        else {
+                /* unconditionally propagate - t already has the updated eff and is at the root,
+                   so we can't detect a change in inheritance, but we know that priority has
+                   indeed increased/changed. */
+                increase_klmirqd = 1;
+        }
+
         hp = container_of(binheap_top_entry(&reg->owners, struct rt_param, gpu_owner_node),
                                           struct task_struct, rt_param);
 
-        if (effective_priority(hp) != hp_eff) { /* the eff. prio. of hp has changed */
+        /* check if the eff. prio. of hp has changed */
+        if (increase_klmirqd || (effective_priority(hp) != hp_eff)) {
                 hp_eff = effective_priority(hp);
-                TRACE_CUR("%s/%d is new hp on GPU %d.\n", t->comm, t->pid, gpu);
+                TRACE_CUR("%s/%d (eff_prio = %s/%d) is new hp on GPU %d.\n",
+                                                t->comm, t->pid,
+                                                hp_eff->comm, hp_eff->pid,
+                                                gpu);
 
                 retval = gpu_klmirqd_increase_priority(reg->thread, hp_eff);
         }
@@ -781,7 +806,8 @@ int gpu_owner_decrease_priority(struct task_struct *t)
                 struct task_struct *new_hp =
                         container_of(binheap_top_entry(&reg->owners, struct rt_param, gpu_owner_node),
                                          struct task_struct, rt_param);
-                if (effective_priority(new_hp) != hp_eff) { /* eff prio. of hp has changed */
+                /* if the new_hp is still t, or if the effective priority has changed */
+                if ((new_hp == t) || (effective_priority(new_hp) != hp_eff)) {
                         hp_eff = effective_priority(new_hp);
                         TRACE_CUR("%s/%d is no longer hp on GPU %d.\n", t->comm, t->pid, gpu);
                         retval = gpu_klmirqd_decrease_priority(reg->thread, hp_eff);