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[#4147] Allow to disable recycling

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Motivation:

Sometimes it is useful to disable recycling completely if memory constraints are very tight.

Modifications:

Allow to use -Dio.netty.recycler.maxCapacity.default=0 to disable recycling completely.

Result:

It's possible to disable recycling now.
This commit is contained in:
Norman Maurer 2015-08-27 11:08:27 +02:00
parent 1ba087bc86
commit 01c29e5cc7
2 changed files with 52 additions and 5 deletions
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24
common/src/main/java/io/netty/util/Recycler.java
View File

@ -36,8 +36,11 @@ public abstract class Recycler<T> {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(Recycler.class);
private static final Handle NOOP_HANDLE = new Handle() { };
private static final AtomicInteger ID_GENERATOR = new AtomicInteger(Integer.MIN_VALUE);
private static final int OWN_THREAD_ID = ID_GENERATOR.getAndIncrement();
// TODO: Some arbitrary large number - should adjust as we get more production experience.
private static final int DEFAULT_INITIAL_MAX_CAPACITY = 262144;
private static final int DEFAULT_MAX_CAPACITY;
private static final int INITIAL_CAPACITY;
@ -45,15 +48,19 @@ public abstract class Recycler<T> {
// In the future, we might have different maxCapacity for different object types.
// e.g. io.netty.recycler.maxCapacity.writeTask
// io.netty.recycler.maxCapacity.outboundBuffer
int maxCapacity = SystemPropertyUtil.getInt("io.netty.recycler.maxCapacity.default", 0);
if (maxCapacity <= 0) {
// TODO: Some arbitrary large number - should adjust as we get more production experience.
maxCapacity = 262144;
int maxCapacity = SystemPropertyUtil.getInt("io.netty.recycler.maxCapacity.default",
DEFAULT_INITIAL_MAX_CAPACITY);
if (maxCapacity < 0) {
maxCapacity = DEFAULT_INITIAL_MAX_CAPACITY;
}
DEFAULT_MAX_CAPACITY = maxCapacity;
if (logger.isDebugEnabled()) {
logger.debug("-Dio.netty.recycler.maxCapacity.default: {}", DEFAULT_MAX_CAPACITY);
if (DEFAULT_MAX_CAPACITY == 0) {
logger.debug("-Dio.netty.recycler.maxCapacity.default: disabled");
} else {
logger.debug("-Dio.netty.recycler.maxCapacity.default: {}", DEFAULT_MAX_CAPACITY);
}
}
INITIAL_CAPACITY = Math.min(DEFAULT_MAX_CAPACITY, 256);
@ -77,6 +84,9 @@ public abstract class Recycler<T> {
@SuppressWarnings("unchecked")
public final T get() {
if (maxCapacity == 0) {
return newObject(NOOP_HANDLE);
}
Stack<T> stack = threadLocal.get();
DefaultHandle handle = stack.pop();
if (handle == null) {
@ -87,6 +97,10 @@ public abstract class Recycler<T> {
}
public final boolean recycle(T o, Handle handle) {
if (handle == NOOP_HANDLE) {
return false;
}
DefaultHandle h = (DefaultHandle) handle;
if (h.stack.parent != this) {
return false;

33
common/src/test/java/io/netty/util/RecyclerTest.java
View File

@ -40,6 +40,15 @@ public class RecyclerTest {
object2.recycle();
}
@Test
public void testRecycleDisable() {
DisabledRecyclableObject object = DisabledRecyclableObject.newInstance();
object.recycle();
DisabledRecyclableObject object2 = DisabledRecyclableObject.newInstance();
assertNotSame(object, object2);
object2.recycle();
}
static final class RecyclableObject {
private static final Recycler<RecyclableObject> RECYCLER = new Recycler<RecyclableObject>() {
@ -64,6 +73,30 @@ public class RecyclerTest {
}
}
static final class DisabledRecyclableObject {
private static final Recycler<DisabledRecyclableObject> RECYCLER = new Recycler<DisabledRecyclableObject>(-1) {
@Override
protected DisabledRecyclableObject newObject(Handle handle) {
return new DisabledRecyclableObject(handle);
}
};
private final Recycler.Handle handle;
private DisabledRecyclableObject(Recycler.Handle handle) {
this.handle = handle;
}
public static DisabledRecyclableObject newInstance() {
return RECYCLER.get();
}
public void recycle() {
RECYCLER.recycle(this, handle);
}
}
/**
* Test to make sure bug #2848 never happens again
* https://github.com/netty/netty/issues/2848