Added inheritance for task pinning. Closes #598 for real.

src/rt/rust_scheduler.cpp

@@ -291,6 +291,8 @@ rust_scheduler::create_task(rust_task *spawner, const char *name) {
         new (this->kernel) rust_task (this, &newborn_tasks, spawner, name);
     DLOG(this, task, "created task: " PTR ", spawner: %s, name: %s",
                         task, spawner ? spawner->name : "null", name);
+    if(spawner)
+        task->pin(spawner->pinned_on);
     newborn_tasks.append(task);
     return task;
 }

src/rt/rust_task.cpp

@@ -528,9 +528,15 @@ rust_task::free(void *mem, memory_region::memory_region_type type) {
 }
 
 void rust_task::pin() {
+    I(this->sched, running_on != -1);
     pinned_on = running_on;
 }
 
+void rust_task::pin(int id) {
+    I(this->sched, running_on == -1);
+    pinned_on = id;
+}
+
 void rust_task::unpin() {
     pinned_on = -1;
 }

src/rt/rust_task.h

@@ -154,6 +154,7 @@ rust_task : public maybe_proxy<rust_task>,
     void free(void *mem, memory_region::memory_region_type type);
 
     void pin();
+    void pin(int id);
     void unpin();
 };