src/hotspot/share/gc/shenandoah/shenandoahArguments.cpp

rev 54386 : 8221766: Load-reference barriers for Shenandoah

*** 44,59 ****
  
    FLAG_SET_DEFAULT(ShenandoahGCHeuristics,           "passive");
  
    FLAG_SET_DEFAULT(ShenandoahSATBBarrier,            false);
    FLAG_SET_DEFAULT(ShenandoahKeepAliveBarrier,       false);
-   FLAG_SET_DEFAULT(ShenandoahWriteBarrier,           false);
-   FLAG_SET_DEFAULT(ShenandoahReadBarrier,            false);
    FLAG_SET_DEFAULT(ShenandoahStoreValEnqueueBarrier, false);
-   FLAG_SET_DEFAULT(ShenandoahStoreValReadBarrier,    false);
    FLAG_SET_DEFAULT(ShenandoahCASBarrier,             false);
-   FLAG_SET_DEFAULT(ShenandoahAcmpBarrier,            false);
    FLAG_SET_DEFAULT(ShenandoahCloneBarrier,           false);
  #endif
  
  #ifdef _LP64
    // The optimized ObjArrayChunkedTask takes some bits away from the full 64 addressable
--- 44,55 ----
*** 109,124 ****
  #ifdef ASSERT
    // C2 barrier verification is only reliable when all default barriers are enabled
    if (ShenandoahVerifyOptoBarriers &&
            (!FLAG_IS_DEFAULT(ShenandoahSATBBarrier)            ||
             !FLAG_IS_DEFAULT(ShenandoahKeepAliveBarrier)       ||
-            !FLAG_IS_DEFAULT(ShenandoahWriteBarrier)           ||
-            !FLAG_IS_DEFAULT(ShenandoahReadBarrier)            ||
             !FLAG_IS_DEFAULT(ShenandoahStoreValEnqueueBarrier) ||
-            !FLAG_IS_DEFAULT(ShenandoahStoreValReadBarrier)    ||
             !FLAG_IS_DEFAULT(ShenandoahCASBarrier)             ||
-            !FLAG_IS_DEFAULT(ShenandoahAcmpBarrier)            ||
             !FLAG_IS_DEFAULT(ShenandoahCloneBarrier)
            )) {
      warning("Unusual barrier configuration, disabling C2 barrier verification");
      FLAG_SET_DEFAULT(ShenandoahVerifyOptoBarriers, false);
    }
--- 105,116 ----
*** 162,178 ****
        warning("Shenandoah does not support AOT at this moment, disabling UseAOT");
      }
      FLAG_SET_DEFAULT(UseAOT, false);
    }
  
-   // JNI fast get field stuff is not currently supported by Shenandoah.
-   // It would introduce another heap memory access for reading the forwarding
-   // pointer, which would have to be guarded by the signal handler machinery.
-   // See:
-   // http://mail.openjdk.java.net/pipermail/hotspot-dev/2018-June/032763.html
-   FLAG_SET_DEFAULT(UseFastJNIAccessors, false);
- 
    // TLAB sizing policy makes resizing decisions before each GC cycle. It averages
    // historical data, assigning more recent data the weight according to TLABAllocationWeight.
    // Current default is good for generational collectors that run frequent young GCs.
    // With Shenandoah, GC cycles are much less frequent, so we need we need sizing policy
    // to converge faster over smaller number of resizing decisions.
--- 154,163 ----