src/hotspot/share/runtime/biasedLocking.cpp

rev 54697 : imported patch 8221734-v2-merge
rev 54698 : imported patch 8221734-v2

*** 625,635 ****
    // We can revoke the biases of anonymously-biased objects
    // efficiently enough that we should not cause these revocations to
    // update the heuristics because doing so may cause unwanted bulk
    // revocations (which are expensive) to occur.
    markOop mark = obj->mark();
!   if (mark->is_biased_anonymously()) {
      // We are probably trying to revoke the bias of this object due to
      // an identity hash code computation. Try to revoke the bias
      // without a safepoint. This is possible if we can successfully
      // compare-and-exchange an unbiased header into the mark word of
      // the object, meaning that no other thread has raced to acquire
--- 625,635 ----
    // We can revoke the biases of anonymously-biased objects
    // efficiently enough that we should not cause these revocations to
    // update the heuristics because doing so may cause unwanted bulk
    // revocations (which are expensive) to occur.
    markOop mark = obj->mark();
!   if (mark->is_biased_anonymously() && !attempt_rebias) {
      // We are probably trying to revoke the bias of this object due to
      // an identity hash code computation. Try to revoke the bias
      // without a safepoint. This is possible if we can successfully
      // compare-and-exchange an unbiased header into the mark word of
      // the object, meaning that no other thread has raced to acquire
*** 727,737 ****
      return NOT_BIASED;
    } else if (heuristics == HR_SINGLE_REVOKE) {
      markOop mark = obj->mark();
      Klass *k = obj->klass();
      markOop prototype_header = k->prototype_header();
!     if (mark->biased_locker_is((JavaThread*) THREAD) &&
          prototype_header->bias_epoch() == mark->bias_epoch()) {
        // A thread is trying to revoke the bias of an object biased
        // toward it, again likely due to an identity hash code
        // computation. We can again avoid a safepoint in this case
        // since we are only going to walk our own stack. There are no
--- 727,738 ----
      return NOT_BIASED;
    } else if (heuristics == HR_SINGLE_REVOKE) {
      markOop mark = obj->mark();
      Klass *k = obj->klass();
      markOop prototype_header = k->prototype_header();
!     if (mark->has_bias_pattern() &&
!         mark->biased_locker() == ((JavaThread*) THREAD) &&
          prototype_header->bias_epoch() == mark->bias_epoch()) {
        // A thread is trying to revoke the bias of an object biased
        // toward it, again likely due to an identity hash code
        // computation. We can again avoid a safepoint in this case
        // since we are only going to walk our own stack. There are no