8331031: unify os::dont_yield and os::naked_yield across Posix platforms

Reviewed-by: coleenp, mdoerr

src/hotspot/os/aix/os_aix.cpp

@@ -2059,15 +2059,6 @@ size_t os::vm_min_address() {
   return _vm_min_address_default;
 }
 
-// Used to convert frequent JVM_Yield() to nops
-bool os::dont_yield() {
-  return DontYieldALot;
-}
-
-void os::naked_yield() {
-  sched_yield();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // thread priority support
 

src/hotspot/os/bsd/os_bsd.cpp

@@ -1936,15 +1936,6 @@ size_t os::vm_min_address() {
 #endif
 }
 
-// Used to convert frequent JVM_Yield() to nops
-bool os::dont_yield() {
-  return DontYieldALot;
-}
-
-void os::naked_yield() {
-  sched_yield();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // thread priority support
 

src/hotspot/os/linux/os_linux.cpp

@@ -4310,25 +4310,6 @@ size_t os::vm_min_address() {
   return value;
 }
 
-// Used to convert frequent JVM_Yield() to nops
-bool os::dont_yield() {
-  return DontYieldALot;
-}
-
-// Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
-// actually give up the CPU. Since skip buddy (v2.6.28):
-//
-// * Sets the yielding task as skip buddy for current CPU's run queue.
-// * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
-// * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
-//
-// An alternative is calling os::naked_short_nanosleep with a small number to avoid
-// getting re-scheduled immediately.
-//
-void os::naked_yield() {
-  sched_yield();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // thread priority support
 

src/hotspot/os/posix/os_posix.cpp

@@ -854,6 +854,14 @@ void os::_exit(int num) {
   ALLOW_C_FUNCTION(::_exit, ::_exit(num);)
 }
 
+bool os::dont_yield() {
+  return DontYieldALot;
+}
+
+void os::naked_yield() {
+  sched_yield();
+}
+
 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
 // which is used to find statically linked in agents.
 // Parameters: