hotspot/src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.hpp
author johnc
Thu, 09 May 2013 11:16:39 -0700
changeset 17327 4bd0581aa231
parent 15482 470d0b0c09f1
child 20309 7445302daff6
permissions -rw-r--r--
7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich. Reviewed-by: tschatzl, jmasa

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP

#include "memory/cardTableModRefBS.hpp"
#include "memory/memRegion.hpp"
#include "oops/oop.inline.hpp"
#include "utilities/macros.hpp"

#if INCLUDE_ALL_GCS

class DirtyCardQueueSet;

// This barrier is specialized to use a logging barrier to support
// snapshot-at-the-beginning marking.

class G1SATBCardTableModRefBS: public CardTableModRefBSForCTRS {
public:
  // Add "pre_val" to a set of objects that may have been disconnected from the
  // pre-marking object graph.
  static void enqueue(oop pre_val);

  G1SATBCardTableModRefBS(MemRegion whole_heap,
                          int max_covered_regions);

  bool is_a(BarrierSet::Name bsn) {
    return bsn == BarrierSet::G1SATBCT || CardTableModRefBS::is_a(bsn);
  }

  virtual bool has_write_ref_pre_barrier() { return true; }

  // This notes that we don't need to access any BarrierSet data
  // structures, so this can be called from a static context.
  template <class T> static void write_ref_field_pre_static(T* field, oop newVal) {
    T heap_oop = oopDesc::load_heap_oop(field);
    if (!oopDesc::is_null(heap_oop)) {
      enqueue(oopDesc::decode_heap_oop(heap_oop));
    }
  }

  // We export this to make it available in cases where the static
  // type of the barrier set is known.  Note that it is non-virtual.
  template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) {
    write_ref_field_pre_static(field, newVal);
  }

  // These are the more general virtual versions.
  virtual void write_ref_field_pre_work(oop* field, oop new_val) {
    inline_write_ref_field_pre(field, new_val);
  }
  virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) {
    inline_write_ref_field_pre(field, new_val);
  }
  virtual void write_ref_field_pre_work(void* field, oop new_val) {
    guarantee(false, "Not needed");
  }

  template <class T> void write_ref_array_pre_work(T* dst, int count);
  virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
    if (!dest_uninitialized) {
      write_ref_array_pre_work(dst, count);
    }
  }
  virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
    if (!dest_uninitialized) {
      write_ref_array_pre_work(dst, count);
    }
  }
};

// Adds card-table logging to the post-barrier.
// Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
 private:
  DirtyCardQueueSet& _dcqs;
 public:
  G1SATBCardTableLoggingModRefBS(MemRegion whole_heap,
                                 int max_covered_regions);

  bool is_a(BarrierSet::Name bsn) {
    return bsn == BarrierSet::G1SATBCTLogging ||
      G1SATBCardTableModRefBS::is_a(bsn);
  }

  void write_ref_field_work(void* field, oop new_val);

  // Can be called from static contexts.
  static void write_ref_field_static(void* field, oop new_val);

  // NB: if you do a whole-heap invalidation, the "usual invariant" defined
  // above no longer applies.
  void invalidate(MemRegion mr, bool whole_heap = false);

  void write_region_work(MemRegion mr)    { invalidate(mr); }
  void write_ref_array_work(MemRegion mr) { invalidate(mr); }


};


#endif // INCLUDE_ALL_GCS

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP