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6687581: Make CMS work with compressed oops

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Make FreeChunk read markword instead of LSB in _klass pointer to indicate that it's a FreeChunk for compressed oops.

Reviewed-by: ysr, jmasa
This commit is contained in:
Coleen Phillimore 2008-06-09 11:51:19 -04:00
parent 4cce21039e
commit a2d6036a4d
13 changed files with 315 additions and 160 deletions
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2
hotspot/agent/src/share/classes/sun/jvm/hotspot/memory/CompactibleFreeListSpace.java
View file

@ -121,7 +121,7 @@ public class CompactibleFreeListSpace extends CompactibleSpace {
cur = cur.addOffsetTo(adjustObjectSizeInBytes(size));
}
if (FreeChunk.secondWordIndicatesFreeChunk(dbg.getAddressValue(klassOop))) {
if (FreeChunk.indicatesFreeChunk(cur)) {
if (! cur.equals(regionStart)) {
res.add(new MemRegion(regionStart, cur));
}

31
hotspot/agent/src/share/classes/sun/jvm/hotspot/memory/FreeChunk.java
View file

@ -28,6 +28,7 @@ import java.util.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.types.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.oops.*;
public class FreeChunk extends VMObject {
static {
@ -42,13 +43,13 @@ public class FreeChunk extends VMObject {
Type type = db.lookupType("FreeChunk");
nextField = type.getAddressField("_next");
prevField = type.getAddressField("_prev");
sizeField = type.getCIntegerField("_size");
sizeField = type.getAddressField("_size");
}
// Fields
private static AddressField nextField;
private static AddressField prevField;
private static CIntegerField sizeField;
private static AddressField sizeField;
// Accessors
public FreeChunk next() {
@ -61,20 +62,34 @@ public class FreeChunk extends VMObject {
}
public long size() {
return sizeField.getValue(addr);
if (VM.getVM().isCompressedOopsEnabled()) {
Mark mark = new Mark(sizeField.getValue(addr));
return mark.getSize();
} else {
Address size = sizeField.getValue(addr);
Debugger dbg = VM.getVM().getDebugger();
return dbg.getAddressValue(size);
}
}
public FreeChunk(Address addr) {
super(addr);
}
public static boolean secondWordIndicatesFreeChunk(long word) {
return (word & 0x1L) == 0x1L;
public static boolean indicatesFreeChunk(Address cur) {
FreeChunk f = new FreeChunk(cur);
return f.isFree();
}
public boolean isFree() {
Debugger dbg = VM.getVM().getDebugger();
Address prev = prevField.getValue(addr);
return secondWordIndicatesFreeChunk(dbg.getAddressValue(prev));
if (VM.getVM().isCompressedOopsEnabled()) {
Mark mark = new Mark(sizeField.getValue(addr));
return mark.isCmsFreeChunk();
} else {
Address prev = prevField.getValue(addr);
Debugger dbg = VM.getVM().getDebugger();
long word = dbg.getAddressValue(prev);
return (word & 0x1L) == 0x1L;
}
}
}

17
hotspot/agent/src/share/classes/sun/jvm/hotspot/oops/Mark.java
View file

@ -79,6 +79,11 @@ public class Mark extends VMObject {
noHashInPlace = db.lookupLongConstant("markOopDesc::no_hash_in_place").longValue();
noLockInPlace = db.lookupLongConstant("markOopDesc::no_lock_in_place").longValue();
maxAge = db.lookupLongConstant("markOopDesc::max_age").longValue();
/* Constants in markOop used by CMS. */
cmsShift = db.lookupLongConstant("markOopDesc::cms_shift").longValue();
cmsMask = db.lookupLongConstant("markOopDesc::cms_mask").longValue();
sizeShift = db.lookupLongConstant("markOopDesc::size_shift").longValue();
}
// Field accessors
@ -120,6 +125,11 @@ public class Mark extends VMObject {
private static long maxAge;
/* Constants in markOop used by CMS. */
private static long cmsShift;
private static long cmsMask;
private static long sizeShift;
public Mark(Address addr) {
super(addr);
}
@ -290,4 +300,11 @@ public class Mark extends VMObject {
//
// // Recover address of oop from encoded form used in mark
// inline void* decode_pointer() { return clear_lock_bits(); }
// Copy markOop methods for CMS here.
public boolean isCmsFreeChunk() {
return isUnlocked() &&
(Bits.maskBitsLong(value() >> cmsShift, cmsMask) & 0x1L) == 0x1L;
}
public long getSize() { return (long)(value() >> sizeShift); }
}