Motivation:
In the early days of 5.0, we merged ChannelInboundHandler and
ChannelOutboundHandler into ChannelHandler, and introduced the
annotation called 'Skip'. The annotation 'Skip' was introduced to
determine which handler methods are no-op (i.e. simply forwarding the
event to the next handler) so that DefaultChannelHandlerContext doesn't
even need to submit an event-invoking task to an EventExecutor,
significantly reducing the context switches.
However, this introduced a regression for the handlers which implemented
write() but not flush(). Because flush() was skippable for such
handlers, flush() event went through to the next handler before write() does.
To address this problem, we came up with a naive workaround that sets
MASK_FLUSH when MASK_WRITE is set.
Although the previous workaround works fine for many cases, we still
seem to have an event ordering problem. We keep seeing the intermittant
failure of LocalTransportThreadModelTest.testStagedExecution(), because
other handler methods are still skipped.
Modifications:
We do not skip the execution of handler methods annotated with 'Skip'
unless all inbound methods (or all outbound methods) are marked with
'Skip'.
Result:
This change Brings back the event ordering behavior of 4.x, making
LocalTransportThreadModelTest.testStagedExecution() pass.
Motivation:
The old DefaultAttributeMap impl did more synchronization then needed and also did not expose a efficient way to check if an attribute exists with a specific key.
Modifications:
* Rewrite DefaultAttributeMap to not use IdentityHashMap and synchronization on the map directly. The new impl uses a combination of AtomicReferenceArray and synchronization per chain (linked-list). Also access the first Attribute per bucket can be done without any synchronization at all and just uses atomic operations. This should fit for most use-cases pretty weel.
* Add hasAttr(...) implementation
Result:
It's now possible to check for the existence of a attribute without create one. Synchronization is per linked-list and the first entry can even be added via atomic operation.
Motivation:
At the moment we sometimes use only RecvByteBufAllocator.guess() to guess the next size and the use the ByteBufAllocator.* directly to allocate the buffer. We should always use RecvByteBufAllocator.allocate(...) all the time as this makes the behavior easier to adjust.
Modifications:
Change the read() implementations to make use of RecvByteBufAllocator.
Result:
Behavior is more consistent.
Motivation:
DefaultChannelPipeline.firstContext() should return null when the ipeline is empty. This is not the case atm.
Modification:
Fix incorrect check in DefaultChannelPipeline.firstContext() and add unit tests.
Result:
Correctly return null when DefaultChannelPipeline.firstContext() is called on empty pipeline.
Motivation:
Because Thread.currentThread().interrupt() will unblock Selector.select() we need to take special care when check if we need to rebuild the Selector. If the unblock was caused by the interrupt() we will clear it and move on as this is most likely a bug in a custom ChannelHandler or a library the user makes use of.
Modification:
Clear the interrupt state of the Thread if the Selector was unblock because of an interrupt and the returned keys was 0.
Result:
No more busy loop caused by Thread.currentThread().interrupt()
Motivation:
At the moment whenever we add/remove a ChannelHandler with an EventExecutorGroup we have two synchronization points in the execution path. One to find the childInvoker and one for add/remove itself. We can eliminate the former by call findIInvoker in the synchronization block, as we need to synchronize anyway.
Modification:
Remove the usage of AtomicFieldUpdater and the extra synchronization in findInvoker by moving the call of the method in the synchronized(this) block.
Result:
Less synchronization points and volatile reads/writes
Motivation:
As discussed in #2250, it will become much less complicated to implement
deregistration and reregistration of a channel once #2250 is resolved.
Therefore, there's no need to deprecate deregister() and
channelUnregistered().
Modification:
- Undeprecate deregister() and channelUnregistered()
- Remove SuppressWarnings annotations where applicable
Result:
We (including @jakobbuchgraber) are now ready to play with #2250 at
master
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Fix found differences
Result:
4.1 and master got closer.
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Remove ChannelHandlerInvoker.writeAndFlush(...) and the related
implementations.
Result:
4.1 and master got closer.
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Remove ChannelHandlerInvokerUtil.invokeWriteAndFlush(...) as it is not used anyway and not exists in 4.1
Result:
4.1 and master got closer.
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Fix found differences
Result:
4.1 and master got closer.
Motivation:
4 and 5 were diverged long time ago and we recently reverted some of the
early commits in master. We must make sure 4.1 and master are not very
different now.
Modification:
Fix found differences
Result:
4.1 and master got closer.
Motivation:
Due to the complexity of handling deregistration and re-registration of
a channel, we previously decided to remove the deregister() operation
completely to simplify our code. However, we realized that it shouldn't
be that complicated to implement it during our discussion about making
I/O scheduling more flexible and more customizable [1], and thus the
removal of deregistration and re-registration is unnecessary now.
Modification:
- Revert commit c149f4bcc0
- Revert commit e743a27e75
- Make some additional adjustments
Result:
- deregister(), fireChannelUnregistered(), and channelRegistered() were
added back..
- Channel constructors do not require an EventLoop anymore.
[1] https://github.com/netty/netty/issues/2250
Motivation:
I had the NioSocketChannelTest.testFlushCloseReentrance() fail sometimes on one of my linux installation. This change let it pass all the time.
Modification:
Set the SO_SNDBUF to a small value to force split writes
Result:
Test is passing all the time where it was sometimes fail before.
Motivation:
At the moment it is not possible to deregister a LocalChannel without close it.
Modification:
Not close the LocalChannel during dergister
Result:
It will be possible in the future to deregister a LocalChannel and register it to another EventLoop
Motivation:
Once a user implement a custom ChannelHandlerInvoker it is needed to validate the ChannelPromise. We should expose a utility method for this.
Modifications:
Move validatePromise(...) from DefaultChannelHandlerInvoker to ChannelHandlerInvokerUtil and make it public.
Result:
User is able to reuse code
Motivation:
At the moment it is possible to see a NPE when the LocalSocketChannels doRegister() method is called and the LocalSocketChannels doClose() method is called before the registration was completed.
Modifications:
Make sure we delay the actual close until the registration task was executed.
Result:
No more NPE
Motivation:
At the moment ChanneConfig.setAutoRead(false) only is guaranteer to not have an extra channelRead(...) triggered when used from within the channelRead(...) or channelReadComplete(...) method. This is not the correct behaviour as it should also work from other methods that are triggered from within the EventLoop. For example a valid use case is to have it called from within a ChannelFutureListener, which currently not work as expected.
Beside this there is another bug which is kind of related. Currently Channel.read() will not work as expected for OIO as we will stop try to read even if nothing could be read there after one read operation on the socket (when the SO_TIMEOUT kicks in).
Modifications:
Implement the logic the right way for the NIO/OIO/SCTP and native transport, specific to the transport implementation. Also correctly handle Channel.read() for OIO transport by trigger a new read if SO_TIMEOUT was catched.
Result:
It is now also possible to use ChannelConfig.setAutoRead(false) from other methods that are called from within the EventLoop and have direct effect.
Motivation:
At the moment we create a HashMap that holds the MembershipKeys for multicast with every NioDatagramChannel even when most people not need it at al
Modifications:
Lazy create the HashMap when needed.
Result:
Less memory usage and less object creation
Motivation:
When using System.getProperty(...) and various methods to get a ClassLoader it will fail when a SecurityManager is in place.
Modifications:
Use a priveled block if needed. This work is based in the PR #2353 done by @anilsaldhana .
Result:
Code works also when SecurityManager is present
Motivation:
Because we not null out the array entry in the SelectionKey[] which is produced by SelectedSelectionKeySet.flip() we may end up with a few SelectionKeyreferences still hanging around here even after the Channel was closed. As these entries may be present at the end of the SelectionKey[] which is never updated for a long time as not enough SelectionKeys are ready.
Modifications:
Once we access the SelectionKey out of the SelectionKey[] we directly null it out.
Result:
Reference can be GC'ed right away once the Channel was closed.
Motivation:
At the moment we do a Channel.isActive() check in every AbstractChannel.AbstractUnsafe.write(...) call which gives quite some overhead as shown in the profiler when you write fast enough. We can eliminate the check and do something more smart here.
Modifications:
Remove the isActive() check and just check if the ChannelOutboundBuffer was set to null before, which means the Channel was closed. The rest will be handled in flush0() anyway.
Result:
Less overhead when doing many write calls
Motivation:
At the moment an IllegalArgumentException will be thrown if a ChannelPromise is cancelled while propagate through the ChannelPipeline. This is not correct, we should just stop to propagate it as it is valid to cancel at any time.
Modifications:
Stop propagate the operation through the ChannelPipeline once a ChannelPromise is cancelled.
Result:
No more IllegalArgumentException when cancel a ChannelPromise while moving through the ChannelPipeline.
Motivation:
EventLoop overrides the next() method with the same signature of its
super class EventLoopGroup.
Modifications:
Remove the duplicate method declaration from the EventLoop interface.
Result:
Perhaps makes the API slightly more readable as there is one less
method.
Motivation:
At the moment we use the system-wide default selector provider for this invocation of the Java virtual machine when constructing a new NIO channel, which makes using an alternative SelectorProvider practically useless.
This change allows user specify his/her preferred SelectorProvider.
Modifications:
Add SelectorProvider as a param for current `private static *Channel newSocket` method of NioSocketChannel, NioServerSocketChannel and NioDatagramChannel.
Change default constructors of NioSocketChannel, NioServerSocketChannel and NioDatagramChannel to use DEFAULT_SELECTOR_PROVIDER when calling newSocket(SelectorProvider).
Add new constructors for NioSocketChannel, NioServerSocketChannel and NioDatagramChannel which allow user specify his/her preferred SelectorProvider.
Result:
Now users can specify his/her preferred SelectorProvider when constructing an NIO channel.
Motivation:
Some operating systems like Windows 7 uses a valid globally unique EUI-64 MAC address for a virtual device (e.g. 00:00:00:00:00:00:00:E0), and because it's usually longer than the legit MAC-48 address, we should not use the length of MAC address when two MAC addresses are of the same quality. Instead, we should compare the INET address of the NICs before comparing the length of the MAC addresses.
Modification:
Compare the length of MAC addresses as a last resort.
Result:
Correct MAC address detection in Windows with IPv6 enabled.
Motivation:
When there are two MAC addresses which are good enough, we can choose the one with better IP address rather than just choosing the first appeared one.
Modification:
Replace isBetterAddress() with compareAddresses() to make it return if both addresses are in the same preference level.
Add compareAddresses() which compare InetAddresses and use it when compareAddress(byte[], byte[]) returns 0 (same preference)
Result:
More correct primary MAC address detection
Motivation:
As reported in #2331, some query operations in NetworkInterface takes much longer time than we expected. For example, specifying -Djava.net.preferIPv4Stack=true option in Window increases the execution time by more than 4 times. Some Windows systems have more than 20 network interfaces, and this problem gets bigger as the number of unused (virtual) NICs increases.
Modification:
Use NetworkInterface.getInetAddresses() wherever possible.
Before iterating over all NICs reported by NetworkInterface, filter the NICs without proper InetAddresses. This reduces the number of candidates quite a lot.
NetUtil does not query hardware address of NIC in the first place but uses InetAddress.isLoopbackAddress().
Do not call unnecessary query operations on NetworkInterface. Just get hardware address and compare.
Result:
Significantly reduced class initialization time, which should fix#2331.
Motivation:
The current ascii table [1] showing the various states that a ChannelFuture
can be in, but the table is slightly "off" for the 'cause'.
Modifications:
- Updated the ascii table to display nicely.
Result:
Easier to read the states of a ChannelFuture.
[1] http://netty.io/5.0/api/io/netty/channel/ChannelFuture.html
Motivation:
Allow the user to create a NioServerSocketChannel from an existing ServerSocketChannel.
Modifications:
Add an extra constructor
Result:
Now the user is be able to create a NioServerSocketChannel from an existing ServerSocketChannel, like he can do with all the other Nio*Channel implemntations.
Motivation:
Ensure the user know the Channel must be closed to release resources like filehandles.
Modifications:
Add some extra javadoc.
Result:
More clear documentation
Motivation:
At the moment we use SocketChannel.open(), ServerSocketChannel.open() and DatagramSocketChannel.open(...) within the constructor of our
NIO channels. This introduces a bottleneck if you create a lot of connections as these calls delegate to SelectorProvider.provider() which
uses synchronized internal. This change removed the bottleneck.
Modifications:
Obtain a static instance of the SelectorProvider and use SelectorProvider.openSocketChannel(), SelectorProvider.openServerSocketChannel() and
SelectorProvider.openDatagramChannel(). This eliminates the bottleneck as SelectorProvider.provider() is not called on every channel creation.
Result:
Less conditions when create new channels.
Motivation:
Remove the synchronization bottleneck and so speed up things
Modifications:
Introduce a ThreadLocal cache that holds mappings between classes of ChannelHandlerAdapater implementations and the result of checking if the @Sharable annotation is present.
This way we only will need to do the real check one time and server the other calls via the cache. A ThreadLocal and WeakHashMap combo is used to implement the cache
as this way we can minimize the conditions while still be sure we not leak class instances in containers.
Result:
Less conditions during adding ChannelHandlerAdapter to the ChannelPipeline
This also does factor out some logic of ChannelOutboundBuffer. Mainly we not need nioBuffers() for many
transports and also not need to copy from heap to direct buffer. So this functionality was moved to
NioSocketChannelOutboundBuffer. Also introduce a EpollChannelOutboundBuffer which makes use of
memory addresses for all the writes to reduce GC pressure
- Inspired by #2214 by @normanmaurer
- Call setUncancellable() before performing an outbound operation
- Add safeSetSuccess/Failure() and use them wherever
