/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.vm.memmgr.def;
import org.jnode.vm.VmMagic;
import org.jnode.annotation.Inline;
import org.jnode.annotation.MagicPermission;
import org.jnode.vm.classmgr.ObjectFlags;
import org.jnode.vm.classmgr.ObjectLayout;
import org.jnode.vm.classmgr.VmClassType;
import org.jnode.vm.classmgr.VmNormalClass;
import org.jnode.vm.classmgr.VmType;
import org.jnode.vm.facade.ObjectVisitor;
import org.jnode.vm.memmgr.HeapHelper;
import org.vmmagic.pragma.UninterruptiblePragma;
import org.vmmagic.unboxed.Address;
import org.vmmagic.unboxed.Extent;
import org.vmmagic.unboxed.ObjectReference;
import org.vmmagic.unboxed.Offset;
import org.vmmagic.unboxed.Word;
/**
* @author epr
*/
@MagicPermission
final class VmDefaultHeap extends VmAbstractHeap implements ObjectFlags {
/**
* Offset within this heap of the next free memory block
*/
private Address nextFreePtr;
/**
* The allocation bitmap as object, so we won't throw it away in a GC cycle
*/
private Object allocationBitmap;
/**
* The total size of free space
*/
private Extent freeSize;
/**
* Offset (in bytes) from the start of an object to the size of an object
*/
private Offset sizeOffset;
/**
* The next heap (linked list)
*/
private VmDefaultHeap next;
/**
* Initialize this instance
*
* @param heapMgr
*/
public VmDefaultHeap(DefaultHeapManager heapMgr) {
super(heapMgr.getHelper());
}
/**
* Setup the heap object according to the given start-address of the heap.
*
* @param start
* @param heapClass
* @param slotSize
* @return the heap
*/
protected static VmDefaultHeap setupHeap(HeapHelper helper, Address start,
VmNormalClass<VmDefaultHeap> heapClass, int slotSize) {
final int headerSize = ObjectLayout
.objectAlign((ObjectLayout.HEADER_SLOTS + 1) * slotSize);
final Offset vmtOffset = Offset.fromIntSignExtend(ObjectLayout.TIB_SLOT * slotSize);
final Offset sizeOffset = Offset.fromIntSignExtend(-((ObjectLayout.HEADER_SLOTS + 1) * slotSize));
final Offset flagsOffset = Offset.fromIntSignExtend(ObjectLayout.FLAGS_SLOT * slotSize);
// Setup a heap object, so the heap can initialize itself.
final Address heapPtr = start.add(headerSize);
final Word heapObjSize = Word.fromIntZeroExtend(ObjectLayout.objectAlign(heapClass
.getObjectSize()));
final Word flags = Word.fromIntZeroExtend(ObjectFlags.GC_DEFAULT_COLOR);
heapPtr.store(heapObjSize, sizeOffset);
heapPtr.store(flags, flagsOffset);
heapPtr.store(ObjectReference.fromObject(heapClass.getTIB()), vmtOffset);
helper.clear(heapPtr, heapObjSize.toInt());
VmDefaultHeap heap = (VmDefaultHeap) heapPtr.toObjectReference().toObject();
heap.helper = helper;
return heap;
}
/**
* Append a new heap to the end of the linked list of heaps.
*
* @param newHeap
*/
protected final void append(VmDefaultHeap newHeap) {
VmDefaultHeap heap = this;
while (heap.next != null) {
heap = heap.next;
}
heap.next = newHeap;
}
/**
* Gets the next heap in the linked list of heaps.
*
* @return Next heap
*/
@Inline
public final VmDefaultHeap getNext() {
return next;
}
/**
* Initialize this heap
*
* @param start Start address of this heap
* @param end End address of this heap (first address after this heap)
* @param slotSize
*/
protected void initialize(Address start, Address end, int slotSize) {
// Set my variables
this.start = start;
this.end = end;
initializeAbstract(slotSize);
this.sizeOffset = Offset.fromIntSignExtend(-((ObjectLayout.HEADER_SLOTS + 1) * slotSize));
this.headerSize = ObjectLayout.objectAlign(this.headerSize + slotSize);
final int size = getSize();
final Address myAddr = ObjectReference.fromObject(this).toAddress();
final Word mySize = myAddr.loadWord(sizeOffset);
Address firstObject;
if (inHeap(myAddr)) {
firstObject = myAddr.add(mySize).add(headerSize);
} else {
firstObject = start.add(headerSize);
}
// Initialize an allocation bitmap
final int allocationBits = size / ObjectLayout.OBJECT_ALIGN;
final int allocationBitmapSize = ObjectLayout
.objectAlign((allocationBits + 7) / 8);
this.allocationBitmapPtr = firstObject;
final Address bitmapPtr = this.allocationBitmapPtr;
// Make the bitmap an object, so it is easy to manipulate.
bitmapPtr.store(Word.fromIntZeroExtend(allocationBitmapSize), sizeOffset);
bitmapPtr.store(Word.fromIntZeroExtend(GC_DEFAULT_COLOR), flagsOffset);
bitmapPtr.store(ObjectReference.fromObject(VmType.getObjectClass().getTIB()), tibOffset);
firstObject = firstObject.add(allocationBitmapSize + headerSize);
helper.clear(allocationBitmapPtr, allocationBitmapSize);
this.allocationBitmap = allocationBitmapPtr.toObjectReference().toObject();
// Mark this heap in the allocation bitmap
setAllocationBit(this, true);
// Mark the allocation bitmap in the allocation bitmap
setAllocationBit(allocationBitmap, true);
// Initialize the remaining space as free object.
final Word remainingSize = end.toWord().sub(firstObject.toWord());
final Address ptr = firstObject;
ptr.store(remainingSize, sizeOffset);
ptr.store(ObjectReference.fromObject(FREE), tibOffset);
this.nextFreePtr = ptr;
this.freeSize = remainingSize.toExtent();
}
/**
* Allocate a new instance for the given class. Not that this method cannot
* be synchronized, since the synchronization is handled in VmHeap.
*
* @param vmClass
* @param alignedSize
* @return Object Null if no space is left.
*/
protected Object alloc(VmClassType<?> vmClass, int alignedSize) {
if (nextFreePtr.EQ(Address.zero())) { /* This heap is full */
return null;
}
final Offset tibOffset = this.tibOffset;
final Word headerSize = Word.fromIntZeroExtend(this.headerSize);
final Offset flagsOffset = this.flagsOffset;
final Offset sizeOffset = this.sizeOffset;
Word alignedSizeW = Word.fromIntZeroExtend(alignedSize);
final Word totalSize = alignedSizeW.add(headerSize);
final Object tib = vmClass.getTIB();
if (tib == null) {
throw new IllegalArgumentException("vmClass.TIB is null");
}
//final int size = getSize();
Address objectPtr = Address.zero();
lock();
try {
// Search for the first free block that is large enough
//Screen.debug("a");
while (objectPtr == null) {
final Address ptr = nextFreePtr;
final Word objSize = ptr.loadWord(sizeOffset);
final Object objVmt = ptr.loadObjectReference(tibOffset);
final Address nextPtr = ptr.add(objSize.add(headerSize));
if ((objVmt == FREE) && alignedSizeW.LE(objSize)) {
objectPtr = ptr;
} else {
if (!inHeap(nextPtr)) {
// No large enough free space has been found
// A collect may recover smaller free spaces in this
// heap, but we leave that to a GC iteration.
nextFreePtr = Address.zero();
//Screen.debug("B");
return null;
} else {
this.nextFreePtr = nextPtr;
}
}
}
//Screen.debug("A");
final Word curFreeSize = objectPtr.loadWord(sizeOffset);
if (curFreeSize.GT(totalSize)) {
// Block is larger then we need, split it up.
final Word newFreeSize = curFreeSize.sub(totalSize);
/*if (newFreeSize <= headerSize) {
Unsafe.debug("Block splitup failed");
Unsafe.debug("\ncurFreeSize "); Unsafe.debug(curFreeSize);
Unsafe.debug("\ntotalSize "); Unsafe.debug(totalSize);
Unsafe.debug("\nnewFreeSize "); Unsafe.debug(newFreeSize);
Unsafe.debug("\nheaderSize "); Unsafe.debug(headerSize);
throw new Error("Block splitup failed");
}*/
final Address newFreePtr = objectPtr.add(totalSize);
// Set the header for the remaining free block
newFreePtr.store(newFreeSize, sizeOffset);
newFreePtr.store(0, flagsOffset);
newFreePtr.store(ObjectReference.fromObject(FREE), tibOffset);
// Set the next free offset
nextFreePtr = newFreePtr;
} else {
// The block is not large enough to split up, make the
// new object the size of the free block.
alignedSizeW = curFreeSize;
}
// Create the object header
objectPtr.store(alignedSizeW, sizeOffset);
objectPtr.store(0, flagsOffset);
objectPtr.store(ObjectReference.fromObject(tib), tibOffset);
// Mark the object in the allocation bitmap
setAllocationBit(objectPtr, true);
// Fix the freeSize
freeSize = freeSize.sub(alignedSizeW);
} finally {
unlock();
}
// Clear the contents of the object.
helper.clear(objectPtr, alignedSize);
return objectPtr.toObjectReference().toObject();
}
/**
* Mark the given object as free space.
*
* @param object
*/
@Inline
final void free(Object object) {
final Address ptr = ObjectReference.fromObject(object).toAddress();
final Word objSize = ptr.loadWord(sizeOffset);
ptr.store(ObjectReference.fromObject(FREE), tibOffset);
setAllocationBit(object, false);
freeSize = freeSize.add(objSize);
}
/**
* @return The free size
* @see VmAbstractHeap#getFreeSize()
*/
protected Extent getFreeSize() {
return freeSize;
}
/**
* Join all adjacent free spaces.
*
* @throws UninterruptiblePragma
*/
protected final void defragment() throws UninterruptiblePragma {
final Word size = Word.fromIntZeroExtend(getSize());
final Word headerSize = Word.fromIntZeroExtend(this.headerSize);
Word offset = headerSize;
final Offset sizeOffset = this.sizeOffset;
final Offset tibOffset = this.tibOffset;
lock();
try {
Address firstFreePtr = Address.zero();
while (offset.LT(size)) {
final Address ptr = start.add(offset);
final Word objSize = ptr.loadWord(sizeOffset);
final Word nextOffset = offset.add(objSize).add(headerSize);
final Object vmt = ptr.loadObjectReference(tibOffset);
if ((firstFreePtr == null) && (vmt == FREE)) {
firstFreePtr = ptr;
}
if ((vmt == FREE) && (nextOffset.LT(size))) {
final Object nextVmt;
final Address nextObjectPtr = start.add(nextOffset);
nextVmt = nextObjectPtr.loadObjectReference(tibOffset);
if (nextVmt == FREE) {
// Combine two free spaces
Word nextObjSize = nextObjectPtr.loadWord(sizeOffset);
Word newObjSize = objSize.add(headerSize).add(nextObjSize);
ptr.store(newObjSize, sizeOffset);
// Do not increment offset here, because there may be
// another next free object, which we will combine
// in the next loop.
} else {
offset = nextOffset;
}
} else {
offset = nextOffset;
}
}
// Set the address of the next free block, to the first free block
this.nextFreePtr = firstFreePtr;
} finally {
unlock();
}
}
/**
* Let all objects in this heap make a visit to the given visitor.
*
* @param visitor
* @param locking If true, use lock/unlock while proceeding to the next object.
*/
protected final void walk(ObjectVisitor visitor, boolean locking,
Word flagsMask, Word flagsValue) {
// Go through the heap and call visit on each object
final Word headerSize = Word.fromIntZeroExtend(this.headerSize);
final Offset sizeOffset = this.sizeOffset;
final Offset tibOffset = this.tibOffset;
final Object FREE = this.FREE;
Word offset = headerSize;
final Word size = Word.fromIntZeroExtend(getSize());
if (locking) {
while (offset.LT(size)) {
final Object tib;
final Object object;
final Word objSize;
final Word flags;
lock();
try {
final Address ptr = start.add(offset);
object = ptr.toObjectReference().toObject();
tib = ptr.loadObjectReference(tibOffset);
objSize = ptr.loadWord(sizeOffset);
flags = (flagsMask.isZero()) ? Word.zero() : VmMagic.getObjectFlags(object).and(flagsMask);
} finally {
unlock();
}
if (tib != FREE) {
if (flags.EQ(flagsValue)) {
if (!visitor.visit(object)) {
// Stop
return;
}
}
}
offset = offset.add(objSize).add(headerSize);
}
} else {
while (offset.LT(size)) {
final Address ptr = start.add(offset);
final Object object = ptr.toObjectReference().toObject();
final Object tib = ptr.loadObjectReference(tibOffset);
final Word objSize = ptr.loadWord(sizeOffset);
final Word flags = flagsMask.isZero() ? Word.zero() : VmMagic.getObjectFlags(object).and(flagsMask);
if (tib != FREE) {
if (flags.EQ(flagsValue)) {
if (!visitor.visit(object)) {
// Stop
return;
}
}
}
offset = offset.add(objSize).add(headerSize);
}
}
}
}