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src/hotspot/share/gc/shenandoah/heuristics/shenandoahStaticHeuristics.cpp

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  23 
  24 #include "precompiled.hpp"
  25 
  26 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
  27 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
  28 #include "gc/shenandoah/shenandoahFreeSet.hpp"
  29 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
  30 #include "logging/log.hpp"
  31 #include "logging/logTag.hpp"
  32 
  33 ShenandoahStaticHeuristics::ShenandoahStaticHeuristics() : ShenandoahHeuristics() {
  34   // Static heuristics may degrade to continuous if live data is larger
  35   // than free threshold. ShenandoahAllocationThreshold is supposed to break this,
  36   // but it only works if it is non-zero.
  37   SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 1);
  38 
  39   SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
  40   SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);
  41 
  42   // Final configuration checks

  43   SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);
  44   SHENANDOAH_CHECK_FLAG_SET(ShenandoahReadBarrier);
  45   SHENANDOAH_CHECK_FLAG_SET(ShenandoahWriteBarrier);
  46   SHENANDOAH_CHECK_FLAG_SET(ShenandoahStoreValReadBarrier);
  47   SHENANDOAH_CHECK_FLAG_SET(ShenandoahKeepAliveBarrier);
  48   SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);
  49   SHENANDOAH_CHECK_FLAG_SET(ShenandoahAcmpBarrier);
  50   SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);
  51 }
  52 
  53 ShenandoahStaticHeuristics::~ShenandoahStaticHeuristics() {}
  54 
  55 bool ShenandoahStaticHeuristics::should_start_normal_gc() const {
  56   ShenandoahHeap* heap = ShenandoahHeap::heap();
  57 
  58   size_t capacity = heap->capacity();
  59   size_t available = heap->free_set()->available();
  60   size_t threshold_available = (capacity * ShenandoahFreeThreshold) / 100;
  61 
  62   if (available < threshold_available) {
  63     log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is below free threshold (" SIZE_FORMAT "M)",
  64                  available / M, threshold_available / M);
  65     return true;
  66   }
  67   return ShenandoahHeuristics::should_start_normal_gc();
  68 }
  69 




  23 
  24 #include "precompiled.hpp"
  25 
  26 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
  27 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
  28 #include "gc/shenandoah/shenandoahFreeSet.hpp"
  29 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
  30 #include "logging/log.hpp"
  31 #include "logging/logTag.hpp"
  32 
  33 ShenandoahStaticHeuristics::ShenandoahStaticHeuristics() : ShenandoahHeuristics() {
  34   // Static heuristics may degrade to continuous if live data is larger
  35   // than free threshold. ShenandoahAllocationThreshold is supposed to break this,
  36   // but it only works if it is non-zero.
  37   SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 1);
  38 
  39   SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent);
  40   SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent);
  41 
  42   // Final configuration checks
  43   SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier);
  44   SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);



  45   SHENANDOAH_CHECK_FLAG_SET(ShenandoahKeepAliveBarrier);
  46   SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);

  47   SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);
  48 }
  49 
  50 ShenandoahStaticHeuristics::~ShenandoahStaticHeuristics() {}
  51 
  52 bool ShenandoahStaticHeuristics::should_start_normal_gc() const {
  53   ShenandoahHeap* heap = ShenandoahHeap::heap();
  54 
  55   size_t capacity = heap->capacity();
  56   size_t available = heap->free_set()->available();
  57   size_t threshold_available = (capacity * ShenandoahFreeThreshold) / 100;
  58 
  59   if (available < threshold_available) {
  60     log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is below free threshold (" SIZE_FORMAT "M)",
  61                  available / M, threshold_available / M);
  62     return true;
  63   }
  64   return ShenandoahHeuristics::should_start_normal_gc();
  65 }
  66 


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