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package sun.jvm.hotspot.gc.shared;

import java.io.*;
import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.memory.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.utilities.Observable;
import sun.jvm.hotspot.utilities.Observer;

The (supported) Generation hierarchy currently looks like this:

  • Generation
    • CardGeneration
      • TenuredGeneration
    • DefNewGeneration
/** <P> The (supported) Generation hierarchy currently looks like this: </P> <ul> <li> Generation <ul> <li> CardGeneration <ul> <li> TenuredGeneration </ul> <li> DefNewGeneration </ul> </ul> */
public abstract class Generation extends VMObject { private static long reservedFieldOffset; private static long virtualSpaceFieldOffset; protected static final int K = 1024; // Fields for class StatRecord private static Field statRecordField; private static CIntegerField invocationField; // constants from Name enum private static int NAME_DEF_NEW; private static int NAME_PAR_NEW; private static int NAME_MARK_SWEEP_COMPACT; private static int NAME_CONCURRENT_MARK_SWEEP; private static int NAME_OTHER; static { VM.registerVMInitializedObserver(new Observer() { public void update(Observable o, Object data) { initialize(VM.getVM().getTypeDataBase()); } }); } private static synchronized void initialize(TypeDataBase db) { Type type = db.lookupType("Generation"); reservedFieldOffset = type.getField("_reserved").getOffset(); virtualSpaceFieldOffset = type.getField("_virtual_space").getOffset(); // StatRecord statRecordField = type.getField("_stat_record"); type = db.lookupType("Generation::StatRecord"); invocationField = type.getCIntegerField("invocations"); // constants from Generation::Name NAME_DEF_NEW = db.lookupIntConstant("Generation::DefNew").intValue(); NAME_MARK_SWEEP_COMPACT = db.lookupIntConstant("Generation::MarkSweepCompact").intValue(); NAME_OTHER = db.lookupIntConstant("Generation::Other").intValue(); } public Generation(Address addr) { super(addr); } public static class Name { public static final Name DEF_NEW = new Name("DefNew"); public static final Name MARK_SWEEP_COMPACT = new Name("MarkSweepCompact"); public static final Name OTHER = new Name("Other"); private Name(String value) { this.value = value; } private String value; public String toString() { return value; } } public Generation.Name kind() { return Generation.Name.OTHER; } static Generation.Name nameForEnum(int value) { if (value == NAME_DEF_NEW) { return Name.DEF_NEW; } else if (value == NAME_MARK_SWEEP_COMPACT) { return Name.MARK_SWEEP_COMPACT; } else if (value == NAME_OTHER) { return Name.OTHER; } else { throw new RuntimeException("should not reach here"); } } public int invocations() { return getStatRecord().getInvocations(); }
The maximum number of object bytes the generation can currently hold.
/** The maximum number of object bytes the generation can currently hold. */
public abstract long capacity();
The number of used bytes in the gen.
/** The number of used bytes in the gen. */
public abstract long used();
The number of free bytes in the gen.
/** The number of free bytes in the gen. */
public abstract long free();
The largest number of contiguous free words in the generation, including expansion. (VM's version assumes it is called at a safepoint.)
/** The largest number of contiguous free words in the generation, including expansion. (VM's version assumes it is called at a safepoint.) */
public abstract long contiguousAvailable(); public MemRegion reserved() { return new MemRegion(addr.addOffsetTo(reservedFieldOffset)); }
Returns a region guaranteed to contain all the objects in the generation.
/** Returns a region guaranteed to contain all the objects in the generation. */
public MemRegion usedRegion() { return reserved(); } /* Returns "TRUE" iff "p" points into an allocated object in the generation. */ public boolean isIn(Address p) { GenerationIsInClosure blk = new GenerationIsInClosure(p); spaceIterate(blk); return (blk.space() != null); }
Returns "TRUE" iff "p" points into the reserved area of the generation.
/** Returns "TRUE" iff "p" points into the reserved area of the generation. */
public boolean isInReserved(Address p) { return reserved().contains(p); } protected VirtualSpace virtualSpace() { return (VirtualSpace) VMObjectFactory.newObject(VirtualSpace.class, addr.addOffsetTo(virtualSpaceFieldOffset)); } public abstract String name();
Equivalent to spaceIterate(blk, false)
/** Equivalent to spaceIterate(blk, false) */
public void spaceIterate(SpaceClosure blk) { spaceIterate(blk, false); }
Iteration - do not use for time critical operations
/** Iteration - do not use for time critical operations */
public abstract void spaceIterate(SpaceClosure blk, boolean usedOnly); public abstract void liveRegionsIterate(LiveRegionsClosure closure); public void print() { printOn(System.out); } public abstract void printOn(PrintStream tty); public static class StatRecord extends VMObject { public StatRecord(Address addr) { super(addr); } public int getInvocations() { return (int) invocationField.getValue(addr); } } private StatRecord getStatRecord() { return (StatRecord) VMObjectFactory.newObject(Generation.StatRecord.class, addr.addOffsetTo(statRecordField.getOffset())); } }