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Fix a bug in PoolArena and PoolSubpage where subpage pools are not updated correctly

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- Make PoolSubpage a linked list node in the pool
- Now that a subpage is added to and removed from the pool correctly, allocating a subpage from the pool became vastly simpler.
This commit is contained in:
Trustin Lee 2013-03-05 23:55:41 +09:00
parent 6e5bb87219
commit 5f2c2cdc9b
3 changed files with 90 additions and 53 deletions
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84
buffer/src/main/java/io/netty/buffer/PoolArena.java
View File

@ -20,8 +20,6 @@ import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.StringUtil;
import java.nio.ByteBuffer;
import java.util.ArrayDeque;
import java.util.Deque;
abstract class PoolArena<T> {
@ -33,8 +31,8 @@ abstract class PoolArena<T> {
private final int chunkSize;
private final int subpageOverflowMask;
private final Deque<PoolSubpage<T>>[] tinySubpagePools;
private final Deque<PoolSubpage<T>>[] smallSubpagePools;
private final PoolSubpage<T>[] tinySubpagePools;
private final PoolSubpage<T>[] smallSubpagePools;
private final PoolChunkList<T> q050;
private final PoolChunkList<T> q025;
@ -56,12 +54,12 @@ abstract class PoolArena<T> {
tinySubpagePools = newSubpagePoolArray(512 >>> 4);
for (int i = 0; i < tinySubpagePools.length; i ++) {
tinySubpagePools[i] = new ArrayDeque<PoolSubpage<T>>();
tinySubpagePools[i] = newSubpagePoolHead(pageSize);
}
smallSubpagePools = newSubpagePoolArray(pageShifts - 9);
for (int i = 0; i < smallSubpagePools.length; i ++) {
smallSubpagePools[i] = new ArrayDeque<PoolSubpage<T>>();
smallSubpagePools[i] = newSubpagePoolHead(pageSize);
}
q100 = new PoolChunkList<T>(this, null, 100, Integer.MAX_VALUE);
@ -79,9 +77,16 @@ abstract class PoolArena<T> {
qInit.prevList = qInit;
}
private PoolSubpage<T> newSubpagePoolHead(int pageSize) {
PoolSubpage<T> head = new PoolSubpage<T>(pageSize);
head.prev = head;
head.next = head;
return head;
}
@SuppressWarnings("unchecked")
private Deque<PoolSubpage<T>>[] newSubpagePoolArray(int size) {
return new Deque[size];
private PoolSubpage<T>[] newSubpagePoolArray(int size) {
return new PoolSubpage[size];
}
PooledByteBuf<T> allocate(PoolThreadCache cache, int reqCapacity, int maxCapacity) {
@ -94,7 +99,7 @@ abstract class PoolArena<T> {
final int normCapacity = normalizeCapacity(reqCapacity);
if ((normCapacity & subpageOverflowMask) == 0) { // capacity < pageSize
int tableIdx;
Deque<PoolSubpage<T>>[] table;
PoolSubpage<T>[] table;
if ((normCapacity & 0xFFFFFE00) == 0) { // < 512
tableIdx = normCapacity >>> 4;
table = tinySubpagePools;
@ -109,26 +114,14 @@ abstract class PoolArena<T> {
}
synchronized (this) {
Deque<PoolSubpage<T>> subpages = table[tableIdx];
for (;;) {
PoolSubpage<T> s = subpages.peekFirst();
if (s == null) {
break;
}
if (!s.doNotDestroy || s.elemSize != normCapacity) {
// The subpage has been destroyed or being used for different element size.
subpages.removeFirst();
continue;
}
final PoolSubpage<T> head = table[tableIdx];
final PoolSubpage<T> s = head.next;
if (s != head) {
assert s.doNotDestroy && s.elemSize == normCapacity;
long handle = s.allocate();
if (handle < 0) {
subpages.removeFirst();
} else {
s.chunk.initBufWithSubpage(buf, handle, reqCapacity);
return;
}
assert handle >= 0;
s.chunk.initBufWithSubpage(buf, handle, reqCapacity);
return;
}
}
} else if (normCapacity > chunkSize) {
@ -142,7 +135,7 @@ abstract class PoolArena<T> {
private synchronized void allocateNormal(PooledByteBuf<T> buf, int reqCapacity, int normCapacity) {
if (q050.allocate(buf, reqCapacity, normCapacity) || q025.allocate(buf, reqCapacity, normCapacity) ||
q000.allocate(buf, reqCapacity, normCapacity) || qInit.allocate(buf, reqCapacity, normCapacity) ||
q075.allocate(buf, reqCapacity, normCapacity)) {
q075.allocate(buf, reqCapacity, normCapacity) || q100.allocate(buf, reqCapacity, normCapacity)) {
return;
}
@ -166,10 +159,9 @@ abstract class PoolArena<T> {
}
}
void addSubpage(PoolSubpage<T> subpage) {
PoolSubpage<T> findSubpagePoolHead(int elemSize) {
int tableIdx;
int elemSize = subpage.elemSize;
Deque<PoolSubpage<T>>[] table;
PoolSubpage<T>[] table;
if ((elemSize & 0xFFFFFE00) == 0) { // < 512
tableIdx = elemSize >>> 4;
table = tinySubpagePools;
@ -183,7 +175,7 @@ abstract class PoolArena<T> {
table = smallSubpagePools;
}
table[tableIdx].addFirst(subpage);
return table[tableIdx];
}
private int normalizeCapacity(int reqCapacity) {
@ -288,28 +280,42 @@ abstract class PoolArena<T> {
buf.append(StringUtil.NEWLINE);
buf.append("tiny subpages:");
for (int i = 1; i < tinySubpagePools.length; i ++) {
Deque<PoolSubpage<T>> subpages = tinySubpagePools[i];
if (subpages.isEmpty()) {
PoolSubpage<T> head = tinySubpagePools[i];
if (head.next == head) {
continue;
}
buf.append(StringUtil.NEWLINE);
buf.append(i);
buf.append(": ");
buf.append(subpages);
PoolSubpage<T> s = head.next;
for (;;) {
buf.append(s);
s = s.next;
if (s == head) {
break;
}
}
}
buf.append(StringUtil.NEWLINE);
buf.append("small subpages:");
for (int i = 1; i < smallSubpagePools.length; i ++) {
Deque<PoolSubpage<T>> subpages = smallSubpagePools[i];
if (subpages.isEmpty()) {
PoolSubpage<T> head = smallSubpagePools[i];
if (head.next == head) {
continue;
}
buf.append(StringUtil.NEWLINE);
buf.append(i);
buf.append(": ");
buf.append(subpages);
PoolSubpage<T> s = head.next;
for (;;) {
buf.append(s);
s = s.next;
if (s == head) {
break;
}
}
}
buf.append(StringUtil.NEWLINE);

1
buffer/src/main/java/io/netty/buffer/PoolChunk.java
View File

@ -214,7 +214,6 @@ final class PoolChunk<T> {
} else {
subpage.init(normCapacity);
}
arena.addSubpage(subpage);
return subpage.allocate();
}

58
buffer/src/main/java/io/netty/buffer/PoolSubpage.java
View File

@ -24,6 +24,9 @@ final class PoolSubpage<T> {
final int pageSize;
final long[] bitmap;
PoolSubpage<T> prev;
PoolSubpage<T> next;
boolean doNotDestroy;
int elemSize;
int maxNumElems;
@ -34,6 +37,16 @@ final class PoolSubpage<T> {
// TODO: Test if adding padding helps under contention
//private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
/** Special constructor that creates a linked list head */
PoolSubpage(int pageSize) {
chunk = null;
memoryMapIdx = -1;
runOffset = -1;
elemSize = -1;
this.pageSize = pageSize;
bitmap = null;
}
PoolSubpage(PoolChunk<T> chunk, int memoryMapIdx, int runOffset, int pageSize, int elemSize) {
this.chunk = chunk;
this.memoryMapIdx = memoryMapIdx;
@ -46,20 +59,20 @@ final class PoolSubpage<T> {
void init(int elemSize) {
doNotDestroy = true;
this.elemSize = elemSize;
if (elemSize == 0) {
return;
if (elemSize != 0) {
maxNumElems = numAvail = pageSize / elemSize;
nextAvail = 0;
bitmapLength = maxNumElems >>> 6;
if ((maxNumElems & 63) != 0) {
bitmapLength ++;
}
for (int i = 0; i < bitmapLength; i ++) {
bitmap[i] = 0;
}
}
maxNumElems = numAvail = pageSize / elemSize;
nextAvail = 0;
bitmapLength = maxNumElems >>> 6;
if ((maxNumElems & 63) != 0) {
bitmapLength ++;
}
for (int i = 0; i < bitmapLength; i ++) {
bitmap[i] = 0;
}
addToPool();
}
/**
@ -81,6 +94,7 @@ final class PoolSubpage<T> {
bitmap[q] |= 1L << r;
if (-- numAvail == 0) {
removeFromPool();
nextAvail = -1;
} else {
nextAvail = findNextAvailable();
@ -105,7 +119,7 @@ final class PoolSubpage<T> {
if (numAvail ++ == 0) {
nextAvail = bitmapIdx;
chunk.arena.addSubpage(this);
addToPool();
return true;
}
@ -113,10 +127,28 @@ final class PoolSubpage<T> {
return true;
} else {
doNotDestroy = false;
removeFromPool();
return false;
}
}
private void addToPool() {
PoolSubpage<T> head = chunk.arena.findSubpagePoolHead(elemSize);
assert prev == null && next == null;
prev = head;
next = head.next;
next.prev = this;
head.next = this;
}
private void removeFromPool() {
assert prev != null && next != null;
prev.next = next;
next.prev = prev;
next = null;
prev = null;
}
private int findNextAvailable() {
int newNextAvail = -1;
loop: