Motivation
The current event loop shutdown logic is quite fragile and in the
epoll/NIO cases relies on the default 1 second wait/select timeout that
applies when there are no scheduled tasks. Without this default timeout
the shutdown would hang indefinitely.
The timeout only takes effect in this case because queued scheduled
tasks are first cancelled in
SingleThreadEventExecutor#confirmShutdown(), but I _think_ even this
isn't robust, since the main task queue is subsequently serviced which
could result in some new scheduled task being queued with much later
deadline.
It also means shutdowns are unnecessarily delayed by up to 1 second.
Modifications
- Add/extend unit tests to expose the issue
- Adjust SingleThreadEventExecutor shutdown and confirmShutdown methods
to explicitly add no-op tasks to the taskQueue so that the subsequent
event loop iteration doesn't enter blocking wait (as looks like was
originally intended)
Results
Faster and more robust shutdown of event loops, allows removal of the default wait timeout.
This is a port of https://github.com/netty/netty/pull/9616
Motivation:
aebe206 added support for using a ChannelOption to set / get Buffer sizes but did not add the methods to the DomainSocketChannelConfig interface itself (due not be able to break the API)
Modifications:
Add methods to interface (as this is a next major release)
Result:
Easier access to configure these buffer sizes
Motivation:
At the moment we not consistently (and also not correctly) free allocated native memory in all cases during loading the JNI library. This can lead to native memory leaks in the unlikely case of failure while trying to load the library.
Beside this we also not always correctly handle the case when a new java object can not be created in native code because of out of memory.
Modification:
- Copy some macros from netty-tcnative to be able to handle errors in a more easy fashion
- Correctly account for New* functions to return NULL
- Share code
Result:
More robust and clean JNI code
Motivation:
It is not safe to cache a jclass without obtaining a global reference via NewGlobalRef.
Modifications:
Correctly use NewGlobalRef(...) before caching
Result:
Correctly cache jclass instance
Motivation:
Running tests with a `KQueueDomainSocketChannel` showed worse performance than an `NioSocketChannel`. It turns out that the default send buffer size for Nio sockets is 64k while for KQueue sockets it's 8k. I verified that manually setting the socket's send buffer size improved perf to expected levels.
Modification:
Plumb the `SO_SNDBUF` and `SO_RCVBUF` options into the `*DomainSocketChannelConfig`.
Result:
Can now configure send and receive buffer sizes for domain sockets.
Motivation:
We should correctly reset the cached local and remote address when a Channel.disconnect() is called and the channel has a notion of disconnect vs close (for example DatagramChannel implementations).
Modifications:
- Correctly reset cached kicak abd remote address
- Update testcase to cover it and so ensure all transports work in a consistent way
Result:
Correctly handle disconnect()
Motivation:
291f80733a introduced a change to use a byte[] to construct the InetAddress when receiving datagram messages to reduce the overhead. Unfortunally it introduced a regression when handling IPv6-mapped-IPv4 addresses and so produced an IndexOutOfBoundsException when trying to fill the byte[] in native code.
Modifications:
- Correctly use the offset on the pointer of the address.
- Add testcase
- Make tests more robust and include more details when the test fails
Result:
No more IndexOutOfBoundsException
Motivation:
When using datagram sockets which need to handle a lot of packets it makes sense to use recvmmsg to be able to read multiple datagram packets with one syscall.
Modifications:
- Add support for recvmmsg on linux
- Add new EpollChannelOption.MAX_DATAGRAM_PACKET_SIZE
- Add tests
Result:
Fixes https://github.com/netty/netty/issues/8446.
Motivation:
Netty homepage(netty.io) serves both "http" and "https".
It's recommended to use https than http.
Modification:
I changed from "http://netty.io" to "https://netty.io"
Result:
No effects.
Motivation:
Some methods that either override others or are implemented as part of implementation an interface did miss the `@Override` annotation
Modifications:
Add missing `@Override`s
Result:
Code cleanup
Motivation:
This resolves a TODO from the initial transport-native-kqueue implementation, supplying the user with the pid of the local peer client/server process.
Modification:
Inside netty_kqueue_bsdsocket_getPeerCredentials, Call getsockopt with LOCAL_PEERPID and pass it to PeerCredentials constructor.
Add a test case in KQueueSocketTest.
Result:
PeerCredentials now have pid field set. Fixes https://github.com/netty/netty/issues/9213
Motivation:
The current KQueueEventLoop implementation does not process concurrent domain socket channel registration/unregistration in the order they actual
happen since unregistration are delated by an event loop task scheduling. When a domain socket is closed, it's file descriptor might be reused
quickly and therefore trigger a new channel registration using the same descriptor.
Consequently the KQueueEventLoop#add(AbstractKQueueChannel) method will overwrite the current inactive channels having the same descriptor
and the delayed KQueueEventLoop#remove(AbstractKQueueChannel) will remove the active channel that replaced the inactive one.
As active channels are registered, events for this file descriptor won't be processed anymore and the channels will never be closed.
The same problem can also happen in EpollEventLoop. Beside this we also may never remove the AbstractEpollChannel from the internal map
when it is unregistered which will prevent it from be GC'ed
Modifications:
- Change logic of native KQueue and Epoll implementations to ensure we correctly handle the case of FD reuse
- Only try to update kevent / epoll if the Channel is still open (as otherwise it will be handled by kqueue / epoll itself)
- Correctly remove AbstractEpollChannel from internal map in all cases
- Make implementation of closeAll() consistent for Epoll and KQueueEventLoop
Result:
KQueue and Epoll native transports correctly handle FD reuse
Co-authored-by: Norman Maurer <norman_maurer@apple.com>
Motivation:
OOME is occurred by increasing suppressedExceptions because other libraries call Throwable#addSuppressed. As we have no control over what other libraries do we need to ensure this can not lead to OOME.
Modifications:
Only use static instances of the Exceptions if we can either dissable addSuppressed or we run on java6.
Result:
Not possible to OOME because of addSuppressed. Fixes https://github.com/netty/netty/issues/9151.
Motivation
These implementations delegate most of their methods to an existing Handle and previously extended RecvByteBufAllocator.DelegatingHandle. This was reverted in #6322 with the introduction of ExtendedHandle but it's not clear to me why it needed to be - the code looks a lot cleaner.
Modifications
Have (Epoll|KQueue)RecvByteAllocatorHandle extend DelegatingHandle again, while still implementing ExtendedHandle.
Result
Less code.
Motivation:
We currently only cover ipv4 multicast in the testsuite but we should also have tests for ipv6.
Modifications:
- Add test for ipv6
- Ensure we only try to run multicast test for ipv4 / ipv6 if the loopback interface supports it.
Result:
Better test coverage
Motivation:
When kevent(...) returns with EINTR we do not correctly decrement the timespec
structure contents to account for the time duration. This may lead to negative
values for tv_nsec which will result in an EINVAL and raise an IOException to
the event loop selection loop.
Modifications:
Correctly calculate new timeoutTs when EINTR is detected
Result:
Fixes#9013.
Motivation:
In 42742e233f we already added default methods to Channel*Handler and deprecated the Adapter classes to simplify the class hierarchy. With this change we go even further and merge everything into just ChannelHandler. This simplifies things even more in terms of class-hierarchy.
Modifications:
- Merge ChannelInboundHandler | ChannelOutboundHandler into ChannelHandler
- Adjust code to just use ChannelHandler
- Deprecate old interfaces.
Result:
Cleaner and simpler code in terms of class-hierarchy.
Motivation:
Since DomainSocketChannel is a DuplexChannel, which be able to shutdown input or output individually on demands, but ALLOW_HALF_CLOSURE channel option has not been supported yet.
I thought this could be a missing feature of Unix domain socket, so here the PR for it.
Modifications:
1. Added allHalfClosure property both in EpollDomainSocketChannelConfig and KQueueDomainSocketChannelConfig,
2. Enabled isAllowHalfClosure method of native channel to support domain channel config,
3. Created EpollDomainSocketShutdownOutputByPeerTest and KQueueDomainSocketShutdownOutputByPeerTest to verify the change.
Result:
ALLOW_HALF_CLOSURE channel option can be set with DomainSocketChannel, and no more warning of Unknown channel option 'ALLOW_HALF_CLOSURE'.
Motivation:
As we now us java8 as minimum java version we can deprecate ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter and just move the default implementations into the interfaces. This makes things a bit more flexible for the end-user and also simplifies the class-hierarchy.
Modifications:
- Mark ChannelInboundHandlerAdapter and ChannelOutboundHandlerAdapter as deprecated
- Add default implementations to ChannelInboundHandler / ChannelOutboundHandler
- Refactor our code to not use ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter anymore
Result:
Cleanup class-hierarchy and make things a bit more flexible.
Motivation:
`DefaultFileRegion.transferTo` will return 0 all the time when we request more data then the actual file size. This may result in a busy spin while processing the fileregion during writes.
Modifications:
- If we wrote 0 bytes check if the underlying file size is smaller then the requested count and if so throw an IOException
- Add DefaultFileRegionTest
- Add a test to the testsuite
Result:
Fixes https://github.com/netty/netty/issues/8868.
Motivation:
In https://github.com/netty/netty/pull/8665 we changed how we handle the registration of Channels to KQueue but missed to removed some code which would deregister the Channel before it actual closed the underlying socket. This could lead to have events triggered still while not have a mapping to the Channel anymore.
Modifications:
Remove deregister call during socket closure.
Result:
Fixes https://github.com/netty/netty/issues/8849.
Motivation:
The SSLEngine does provide a way to signal to the caller that it may need to execute a blocking / long-running task which then can be offloaded to an Executor to ensure the I/O thread is not blocked. Currently how we handle this in SslHandler is not really optimal as while we offload to the Executor we still block the I/O Thread.
Modifications:
- Correctly support offloading the task to the Executor while suspending processing of SSL in the I/O Thread
- Add new methods to SslContext to specify the Executor when creating a SslHandler
- Remove @deprecated annotations from SslHandler constructor that takes an Executor
- Adjust tests to also run with the Executor to ensure all works as expected.
Result:
Be able to offload long running tasks to an Executor when using SslHandler. Partly fixes https://github.com/netty/netty/issues/7862 and https://github.com/netty/netty/issues/7020.
Motivation:
We missed to extend a few tests from the testsuite and so also run these with our native KQueue and Epoll transport.
Modifications:
Extend tests and so run these for our native transports as well.
Result:
More tests.
Motivation:
We can just use Objects.requireNonNull(...) as a replacement for ObjectUtil.checkNotNull(....)
Modifications:
- Use Objects.requireNonNull(...)
Result:
Less code to maintain.
Motivation:
In the native code EpollDatagramChannel / KQueueDatagramChannel creates a DatagramSocketAddress object for each received UDP datagram even when in connected mode as it uses the recvfrom(...) / recvmsg(...) method. Creating these is quite heavy in terms of allocations as internally, char[], String, Inet4Address, InetAddressHolder, InetSocketAddressHolder, InetAddress[], byte[] objects are getting generated when constructing the object. When in connected mode we can just use regular read(...) calls which do not need to allocate all of these.
Modifications:
- When in connected mode use read(...) and NOT recvfrom(..) / readmsg(...) to reduce allocations when possible.
- Adjust tests to ensure read works as expected when in connected mode.
Result:
Less allocations and GC when using native datagram channels in connected mode. Fixes https://github.com/netty/netty/issues/8770.
Motivation:
We have a utility method to check for > 0 and >0 arguments. We should use it.
Modification:
use checkPositive/checkPositiveOrZero instead of if statement.
Result:
Re-use utility method.
Motivation:
We can use lambdas now as we use Java8.
Modification:
use lambda function for all package, #8751 only migrate transport package.
Result:
Code cleanup.
Motivation:
We need to update to a new checkstyle plugin to allow the usage of lambdas.
Modifications:
- Update to new plugin version.
- Fix checkstyle problems.
Result:
Be able to use checkstyle plugin which supports new Java syntax.
* Decouble EventLoop details from the IO handling for each transport to allow easy re-use of code and customization
Motiviation:
As today extending EventLoop implementations to add custom logic / metrics / instrumentations is only possible in a very limited way if at all. This is due the fact that most implementations are final or even package-private. That said even if these would be public there are the ability to do something useful with these is very limited as the IO processing and task processing are very tightly coupled. All of the mentioned things are a big pain point in netty 4.x and need improvement.
Modifications:
This changeset decoubled the IO processing logic from the task processing logic for the main transport (NIO, Epoll, KQueue) by introducing the concept of an IoHandler. The IoHandler itself is responsible to wait for IO readiness and process these IO events. The execution of the IoHandler itself is done by the SingleThreadEventLoop as part of its EventLoop processing. This allows to use the same EventLoopGroup (MultiThreadEventLoupGroup) for all the mentioned transports by just specify a different IoHandlerFactory during construction.
Beside this core API change this changeset also allows to easily extend SingleThreadEventExecutor / SingleThreadEventLoop to add custom logic to it which then can be reused by all the transports. The ideas are very similar to what is provided by ScheduledThreadPoolExecutor (that is part of the JDK). This allows for example things like:
* Adding instrumentation / metrics:
* how many Channels are registered on an SingleThreadEventLoop
* how many Channels were handled during the IO processing in an EventLoop run
* how many task were handled during the last EventLoop / EventExecutor run
* how many outstanding tasks we have
...
...
* Implementing custom strategies for choosing the next EventExecutor / EventLoop to use based on these metrics.
* Use different Promise / Future / ScheduledFuture implementations
* decorate Runnable / Callables when submitted to the EventExecutor / EventLoop
As a lot of functionalities are folded into the MultiThreadEventLoopGroup and SingleThreadEventLoopGroup this changeset also removes:
* AbstractEventLoop
* AbstractEventLoopGroup
* EventExecutorChooser
* EventExecutorChooserFactory
* DefaultEventLoopGroup
* DefaultEventExecutor
* DefaultEventExecutorGroup
Result:
Fixes https://github.com/netty/netty/issues/8514 .
Motivation:
We can use the diamond operator these days.
Modification:
Use diamond operator whenever possible.
Result:
More modern code and less boiler-plate.
Motiviation:
Because of how we implemented the registration / deregistration of an EventLoop it was not possible to wrap an EventLoop implementation and use it with a Channel.
Modification:
- Introduce EventLoop.Unsafe which is responsible for the actual registration.
- Move validation of EventLoop / Channel combo to the EventLoop
- Add unit test that verifies that wrapping works
Result:
Be able to wrap an EventLoop and so add some extra functionality.
Motivation:
At the moment it’s possible to have a Channel in Netty that is not registered / assigned to an EventLoop until register(...) is called. This is suboptimal as if the Channel is not registered it is also not possible to do anything useful with a ChannelFuture that belongs to the Channel. We should think about if we should have the EventLoop as a constructor argument of a Channel and have the register / deregister method only have the effect of add a Channel to KQueue/Epoll/... It is also currently possible to deregister a Channel from one EventLoop and register it with another EventLoop. This operation defeats the threading model assumptions that are wide spread in Netty, and requires careful user level coordination to pull off without any concurrency issues. It is not a commonly used feature in practice, may be better handled by other means (e.g. client side load balancing), and therefore we propose removing this feature.
Modifications:
- Change all Channel implementations to require an EventLoop for construction ( + an EventLoopGroup for all ServerChannel implementations)
- Remove all register(...) methods from EventLoopGroup
- Add ChannelOutboundInvoker.register(...) which now basically means we want to register on the EventLoop for IO.
- Change ChannelUnsafe.register(...) to not take an EventLoop as parameter (as the EventLoop is supplied on custruction).
- Change ChannelFactory to take an EventLoop to create new Channels and introduce ServerChannelFactory which takes an EventLoop and one EventLoopGroup to create new ServerChannel instances.
- Add ServerChannel.childEventLoopGroup()
- Ensure all operations on the accepted Channel is done in the EventLoop of the Channel in ServerBootstrap
- Change unit tests for new behaviour
Result:
A Channel always has an EventLoop assigned which will never change during its life-time. This ensures we are always be able to call any operation on the Channel once constructed (unit the EventLoop is shutdown). This also simplifies the logic in DefaultChannelPipeline a lot as we can always call handlerAdded / handlerRemoved directly without the need to wait for register() to happen.
Also note that its still possible to deregister a Channel and register it again. It's just not possible anymore to move from one EventLoop to another (which was not really safe anyway).
Fixes https://github.com/netty/netty/issues/8513.
Motivation:
How we did the mapping from native code to AbstractKQueueChannel was not safe and could lead to heap corruption. This then sometimes produced ClassCastExceptions or could also lead to crashes. This happened sometimes when running the testsuite.
Modifications:
Use a Map for the mapping (just as we do in the native epoll transport).
Result:
No more heap corruption / crashes.
* Handling AUTO_READ should not be the responsibility of DefaultChannelPipeline but the Channel itself.
Motivation:
At the moment we do automatically call read() in the DefaultChannelPipeline when fireChannelReadComplete() / fireChannelActive() is called and the Channel is using auto read. This is nice in terms of sharing code but imho is not the responsibility of the ChannelPipeline implementation but the responsibility of the Channel implementation.
Modifications:
Move handing of auto read from DefaultChannelPipeline to Channel implementations.
Result:
More clear responsibiliy and not depending on implemention details of the ChannelPipeline.
Motivation:
Add an option (through a SelectStrategy return code) to have the Netty event loop thread to do busy-wait on the epoll.
The reason for this change is to avoid the context switch cost that comes when the event loop thread is blocked on the epoll_wait() call.
On average, the context switch has a penalty of ~13usec.
This benefits both:
The latency when reading from a socket
Scheduling tasks to be executed on the event loop thread.
The tradeoff, when enabling this feature, is that the event loop thread will be using 100% cpu, even when inactive.
Modification:
Added SelectStrategy option to return BUSY_WAIT
Epoll loop will do a epoll_wait() with no timeout
Use pause instruction to hint to processor that we're in a busy loop
Result:
When enabled, minimizes impact of context switch in the critical path
Motivation
The EpollChannelConfig (same for KQueues) and its subclasses repeatetly declare their own channel field which leads to a 3x repetition for each config instance. Given the fields are protected or package-private it's exposing the code code to "field hiding" bugs.
Modifications
Use the the existing protected channel field from the DefaultChannelConfig class and simply cast it when needed.
Result
Fixes#8331
Motivation:
We should ensure we call *UnLoad when we detect an error during calling *OnLoad and previous *OnLoad calls were succesfull.
Modifications:
Correctly call *UnLoad when needed.
Result:
More correct code and no leaks when an error happens during loading the native lib.
* Allow to use native transports when sun.misc.Unsafe is not present on the system
Motivation:
We should be able to use the native transports (epoll / kqueue) even when sun.misc.Unsafe is not present on the system. This is especially important as Java11 will be released soon and does not allow access to it by default.
Modifications:
- Correctly disable usage of sun.misc.Unsafe when -PnoUnsafe is used while running the build
- Correctly increment metric when UnpooledDirectByteBuf is allocated. This was uncovered once -PnoUnsafe usage was fixed.
- Implement fallbacks in all our native transport code for when sun.misc.Unsafe is not present.
Result:
Fixes https://github.com/netty/netty/issues/8229.
Motivation:
We should support to load multiple shaded versions of the same netty artifact as netty is often used in multiple dependencies.
This is related to https://github.com/netty/netty/issues/7272.
Modifications:
- Use -fvisibility=hidden when compiling and use JNIEXPORT for things we really want to have exported
- Ensure fields are declared as static so these are not exported
- Adjust testsuite-shading to use install_name_tool on MacOS to change the id of the lib. Otherwise the wrong may be used.
Result:
Be able to use multiple shaded versions of the same netty artifact.
Motivation:
Epoll and Kqueue channels have internal state which forces
a single read operation after channel construction. This
violates the Channel#read() interface which indicates that
data shouldn't be delivered until this method is called.
The behavior is also inconsistent with the NIO transport.
Modifications:
- Epoll and Kqueue shouldn't unconditionally read upon
initialization, and instead should rely upon Channel#read()
or auto_read.
Result:
Epoll and Kqueue are more consistent with NIO.
Motivation:
We should allow to schedule tasks with a delay up to Long.MAX_VALUE as we did pre 4.1.25.Final.
Modifications:
Just ensure we not overflow and put the correct max limits in place when schedule a timer. At worse we will get a wakeup to early and then schedule a new timeout.
Result:
Fixes https://github.com/netty/netty/issues/7970.
* Read until all data is consumed when EOF is detected even if readPending is false and auto-read is disabled.
Motivation:
We should better always notify the user of EOF even if the user did not request any data as otherwise we may never be notified when the remote peer closes the connection. This should be ok as the amount of extra data we may read and so fire through the pipeline is limited by SO_RECVBUF.
Modifications:
- Always drain the socket when EOF is detected.
- Add testcase
Result:
No risk for the user to be not notified of EOF.
Motivation:
Sometimes it's useful to disable native transports / native ssl to debug a problem. We should allow to do so with a system property so people not need to adjust code for this.
Modifications:
Add system properties which allow to disable native transport and native ssl.
Result:
Easier to disable native code usage without code changes.
Motivation:
Using a very huge delay when calling schedule(...) may cause an Selector error when calling select(...) later on. We should gaurd against such a big value.
Modifications:
- Add guard against a very huge value.
- Added tests.
Result:
Fixes [#7365]
Motivation:
AbstractNioByteChannel will detect that the remote end of the socket has
been closed and propagate a user event through the pipeline. However if
the user has auto read on, or calls read again, we may propagate the
same user events again. If the underlying transport continuously
notifies us that there is read activity this will happen in a spin loop
which consumes unnecessary CPU.
Modifications:
- AbstractNioByteChannel's unsafe read() should check if the input side
of the socket has been shutdown before processing the event. This is
consistent with EPOLL and KQUEUE transports.
- add unit test with @normanmaurer's help, and make transports consistent with respect to user events
Result:
No more read spin loop in NIO when the channel is half closed.
