Fix hwuitask & RT priorities

Bug: 15993695

Change-Id: Ib6f07237cb834e8d10f3074f8fb206d27f91859a

libs/hwui/renderthread/RenderThread.cpp

@@ -18,6 +18,9 @@
 
 #include "RenderThread.h"
 
+#if defined(HAVE_PTHREADS)
+#include <sys/resource.h>
+#endif
 #include <gui/DisplayEventReceiver.h>
 #include <utils/Log.h>
 
@@ -244,6 +247,9 @@ void RenderThread::requestVsync() {
 }
 
 bool RenderThread::threadLoop() {
+#if defined(HAVE_PTHREADS)
+    setpriority(PRIO_PROCESS, 0, PRIORITY_DISPLAY);
+#endif
     initThreadLocals();
 
     int timeoutMillis = -1;