Add functions to transition threads to deferred ready or transition states

xtoskrnl/ke/kthread.cc

@@ -75,6 +75,44 @@ KE::KThread::AttachThread(IN OUT PKTHREAD Thread)
     }
 }
 
+/**
+ * Transitions a thread to the ready state and queues it for execution within the dispatcher database.
+ *
+ * @param Thread
+ *        Supplies a pointer to the thread to be dispatched.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+KE::KThread::DispatchReadyThread(IN PKTHREAD Thread)
+{
+    PKPROCESS Process;
+
+    /* Extract the process from the thread's APC state */
+    Process = Thread->ApcState.Process;
+
+    /* Verify if the process and thread are resident in physical memory */
+    if(Process->State != ProcessInMemory)
+    {
+        /* Process is swapped out, place the thread in a transition state */
+        Thread->State = Transition;
+    }
+    else if(!Thread->KernelStackResident)
+    {
+        /* Increment the active stack count and transition the thread */
+        Process->StackCount++;
+        Thread->State = Transition;
+    }
+    else
+    {
+        /* Both process and thread's stack are fully resident, queue the thread for execution */
+        KE::Scheduler::InsertDeferredReadyList(Thread);
+    }
+}
+
 /**
  * Retrieves a pointer to the system's initial executive thread object.
  *
@@ -346,6 +384,28 @@ KE::KThread::InitializeThread(IN PKPROCESS Process,
     return STATUS_SUCCESS;
 }
 
+/**
+ * Prepares a thread for execution by safely acquiring the dispatcher database lock.
+ *
+ * @param Thread
+ *        Supplies a pointer to the thread to be readied.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+KE::KThread::ReadyThread(IN PKTHREAD Thread)
+{
+    /* Raise runlevel to SYNC level and acquire the dispatcher database lock */
+    KE::RaiseRunLevel RunLevel(SYNC_LEVEL);
+    KE::QueuedSpinLockGuard DispatcherGuard(DispatcherLock);
+
+    /* Evaluate residency and queue the thread */
+    DispatchReadyThread(Thread);
+}
+
 /**
  * Suspend APC-built thread NOP routine. It takes no actions.
  *