src/hotspot/share/code/nmethod.cpp

rev 47408 : [mq]: no_cmpxchg_if_null
rev 47401 : [mq]: cmpxchg_if_null
rev 47400 : [mq]: cmpxchg_ptr
rev 47216 : 8187443: Forest Consolidation: Move files to unified layout
Reviewed-by: darcy, ihse

*** 1662,1672 ****
  bool nmethod::test_set_oops_do_mark() {
    assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
    nmethod* observed_mark_link = _oops_do_mark_link;
    if (observed_mark_link == NULL) {
      // Claim this nmethod for this thread to mark.
!     if (Atomic::cmpxchg_if_null(NMETHOD_SENTINEL, &_oops_do_mark_link)) {
        // Atomically append this nmethod (now claimed) to the head of the list:
        nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
        for (;;) {
          nmethod* required_mark_nmethods = observed_mark_nmethods;
          _oops_do_mark_link = required_mark_nmethods;
--- 1662,1672 ----
  bool nmethod::test_set_oops_do_mark() {
    assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");
    nmethod* observed_mark_link = _oops_do_mark_link;
    if (observed_mark_link == NULL) {
      // Claim this nmethod for this thread to mark.
!     if (Atomic::cmpxchg(NMETHOD_SENTINEL, &_oops_do_mark_link, (nmethod*)NULL) == NULL) {
        // Atomically append this nmethod (now claimed) to the head of the list:
        nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;
        for (;;) {
          nmethod* required_mark_nmethods = observed_mark_nmethods;
          _oops_do_mark_link = required_mark_nmethods;
*** 1687,1698 ****
  void nmethod::oops_do_marking_prologue() {
    if (TraceScavenge) { tty->print_cr("[oops_do_marking_prologue"); }
    assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
    // We use cmpxchg instead of regular assignment here because the user
    // may fork a bunch of threads, and we need them all to see the same state.
!   bool observed = Atomic::cmpxchg_if_null(NMETHOD_SENTINEL, &_oops_do_mark_nmethods);
!   guarantee(observed, "no races in this sequential code");
  }
  
  void nmethod::oops_do_marking_epilogue() {
    assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
    nmethod* cur = _oops_do_mark_nmethods;
--- 1687,1698 ----
  void nmethod::oops_do_marking_prologue() {
    if (TraceScavenge) { tty->print_cr("[oops_do_marking_prologue"); }
    assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");
    // We use cmpxchg instead of regular assignment here because the user
    // may fork a bunch of threads, and we need them all to see the same state.
!   nmethod* observed = Atomic::cmpxchg(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, (nmethod*)NULL);
!   guarantee(observed == NULL, "no races in this sequential code");
  }
  
  void nmethod::oops_do_marking_epilogue() {
    assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");
    nmethod* cur = _oops_do_mark_nmethods;