Motivation:
The writeSpinCount currently loops over the same buffer, gathering
write, file write, or other write operation multiple times but will
continue writing until there is nothing left or the OS doesn't accept
any data for that specific write. However if the OS keeps accepting
writes there is no way to limit how much time we spend on a specific
socket. This can lead to unfair consumption of resources dedicated to a
single socket.
We currently don't limit the amount of bytes we attempt to write per
gathering write. If there are many more bytes pending relative to the
SO_SNDBUF size we will end up building iov arrays with more elements
than can be written, which results in extra iteration, conditionals,
and book keeping.
Modifications:
- writeSpinCount should limit the number of system calls we make to
write data, instead of applying to individual write operations
- IovArray should support a maximum number of bytes
- IovArray should support composite buffers of greater than size 1024
- We should auto-scale the amount of data that we attempt to write per
gathering write operation relative to SO_SNDBUF and how much data is
successfully written
- The non-unsafe path should also support a maximum number of bytes,
and respect the IOV_MAX limit
Result:
Write resource consumption can be bounded and gathering writes have
a limit relative to the amount of data which can actually be accepted
by the socket.
Motivation:
We used NetUtil.isIpV4StackPreferred() when loading JNI code which tries to load NetworkInterface in its static initializer. Unfortunally a lock on the NetworkInterface class init may be already hold somewhere else which may cause a loader deadlock.
Modifications:
Add a new Socket.initialize() method that will be called when init the library and pass everything needed to the JNI level so we not need to call back to java.
Result:
Fixes [#7458].
Motivation:
AbstractChannel attempts to "filter" messages which are written [1]. A goal of this process is to copy from heap to direct if necessary. However implementations of this method [2][3] may translate a buffer with 0 readable bytes to EMPTY_BUFFER. This may mask a user error where an empty buffer is written but already released.
Modifications:
Replace safeRelease(...) with release(...) to ensure we propagate reference count issues.
Result:
Fixes [#7383]
Automatic-Module-Name entry provides a stable JDK9 module name, when Netty is used in a modular JDK9 applications. More info: http://blog.joda.org/2017/05/java-se-9-jpms-automatic-modules.html
When Netty migrates to JDK9 in the future, the entry can be replaced by actual module-info descriptor.
Modification:
The POM-s are configured to put the correct module names to the manifest.
Result:
Fixes#7218.
Motivation:
To better isolate OS system calls we should not call getsockopt directly but use our netty_unix_socket_getOption0 function. See is a followup of f115bf5.
Modifications:
Export netty_unix_socket_getOption0 by declaring it in the header file and use it
Result:
Better isolation of system calls.
Motivation:
If a user calls EpollSocketChannelConfig.getOptions() and TCP_FASTOPEN_CONNECT is not supported we throw an exception.
Modifications:
- Just return 0 if ENOPROTOOPT is set.
- Add testcase
Result:
getOptions() works as epxected.
Motivation:
We need to set readPending to false when we detect a EOF while issue a read as otherwise we may not unregister from the Selector / Epoll / KQueue and so keep on receving wakeups.
The important bit is that we may even get a wakeup for a read event but will still will only be able to read 0 bytes from the socket, so we need to be very careful when we clear the readPending. This can happen because we generally using edge-triggered mode for our native transports and because of the nature of edge-triggered we may schedule an read event just to find out there is nothing left to read atm (because we completely drained the socket on the previous read).
Modifications:
Set readPending to false when EOF is detected.
Result:
Fixes [#7255].
This reverts commit 413c7c2cd8 as it introduced an regression when edge-triggered mode is used which is true for our native transports by default. With 413c7c2cd8 included it was possible that we set readPending to false by mistake even if we would be interested in read more.
Motivation:
Linux kernel 4.11 introduced a new socket option,
TCP_FASTOPEN_CONNECT, that greatly simplifies making TCP Fast Open
connections on client side. Usually simply setting the flag before
connect() call is enough, no more changes are required.
Details can be found in kernel commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=19f6d3f3
Modifications:
TCP_FASTOPEN_CONNECT socket option was added to EpollChannelOption
class.
Result:
Netty clients can easily make TCP Fast Open connections. Simply
calling option(EpollChannelOption.TCP_FASTOPEN_CONNECT, true) in
client bootstrap is enough (given recent enough kernel).
Motivation:
readPending is currently only set to false if data is delivered to the application, however this may result in duplicate events being received from the selector in the event that the socket was closed.
Modifications:
- We should set readPending to false before each read attempt for all
transports besides NIO.
- Based upon the Javadocs it is possible that NIO may have spurious
wakeups [1]. In this case we should be more cautious and only set
readPending to false if data was actually read.
[1] https://docs.oracle.com/javase/7/docs/api/java/nio/channels/SelectionKey.html
That a selection key's ready set indicates that its channel is ready for some operation category is a hint, but not a guarantee, that an operation in such a category may be performed by a thread without causing the thread to block.
Result:
Notification from the selector (or simulated events from kqueue/epoll ET) in the event of socket closure.
Fixes https://github.com/netty/netty/issues/7255
Motivation:
Even if it's a super micro-optimization (most JVM could optimize such
cases in runtime), in theory (and according to some perf tests) it
may help a bit. It also makes a code more clear and allows you to
access such methods in the test scope directly, without instance of
the class.
Modifications:
Add 'static' modifier for all methods, where it possible. Mostly in
test scope.
Result:
Cleaner code with proper 'static' modifiers.
Motivation:
There are 2 motivations, the first depends on the second:
Loading Netty Epoll statically stopped working in 4.1.16, due to
`Native` always loading the arch specific shared object. In a
static binary, there is no arch specific SO.
Second, there are a ton of exceptions that can happen when loading
a native library. When loading native code, Netty tries a bunch of
different paths but a failure in any given may not be fatal.
Additionally: turning on debug logging is not always feasible so
exceptions get silently swallowed.
Modifications:
* Change Epoll and Kqueue to try the static load second
* Modify NativeLibraryLoader to record all the locations where
exceptions occur.
* Attempt to use `addSuppressed` from Java 7 if available.
Alternatives Considered:
An alternative would be to record log messages at each failure. If
all load attempts fail, the log messages are printed as warning,
else as debug. The problem with this is there is no `LogRecord` to
create like in java.util.logging. Buffering the args to
logger.log() at the end of the method loses the call site, and
changes the order of events to be confusing.
Another alternative is to teach NativeLibraryLoader about loading
the SO first, and then the static version. This would consolidate
the code fore Epoll, Kqueue, and TCNative. I think this is the
long term better option, but this PR is changing a lot already.
Someone else can take a crack at it later
Results:
Epoll Still Loads and easier debugging.
Motivation:
We used to check for version 6.8 but the latest is 6.9
Modifications:
Update version to 6.9 in the check.
Result:
Be able to cut a release on latest centos version
Motivation:
When SO_LINGER is used we run doClose() on the GlobalEventExecutor by default so we need to ensure we schedule all code that needs to be run on the EventLoop on the EventLoop in doClose. Beside this there are also threading issues when calling shutdownOutput(...)
Modifications:
- Schedule removal from EventLoop to the EventLoop
- Correctly handle shutdownOutput and shutdown in respect with threading-model
- Add unit tests
Result:
Fixes [#7159].
Motivation:
We need to ensure we use the correct osname in the Bundle-NativeCode declaration as declared in:
https://www.osgi.org/developer/specifications/reference/
Modifications:
Update osname to match the spec.
Result:
Correct Bundle-NativeCode entry in the MANIFEST
Motivation:
We should only try to load the native artifacts if the architecture we are currently running on is the same as the one the native libraries were compiled for.
Modifications:
Include architecture in native lib name and append the current arch when trying to load these. This will fail then if its not the same as the arch of the compiled arch.
Result:
Fixes [#7150].
Motivation:
PD and PD0 Both try to find and use Unsafe. If unavailable, they
try to log why and continue on. However, it is not always east to
enable this logging. Chaining exceptions together is much easier
to reach, and the original exception is relevant when Unsafe is
needed.
Modifications:
* Make PD log why PD0 could not be loaded with a trace level log
* Make PD0 remember why Unsafe wasn't available
* Expose unavailability cause through PD for higher level use.
* Make Epoll and KQueue include the reason when failing
Result:
Easier debugging in hard to reconfigure environments
Motivation:
If AutoClose is false and there is a IoException then AbstractChannel will not close the channel but instead just fail flushed element in the ChannelOutboundBuffer. AbstractChannel also notifies of writability changes, which may lead to an infinite loop if the peer has closed its read side of the socket because we will keep accepting more data but continuously fail because the peer isn't accepting writes.
Modifications:
- If the transport throws on a write we should acknowledge that the output side of the channel has been shutdown and cleanup. If the channel can't accept more data because it is full, and still healthy it is not expected to throw. However if the channel is not healthy it will throw and is not expected to accept any more writes. In this case we should shutdown the output for Channels that support this feature and otherwise just close.
- Connection-less protocols like UDP can remain the same because the channel may disconnected temporarily.
- Make sure AbstractUnsafe#shutdownOutput is called because the shutdown on the socket may throw an exception.
Result:
More correct handling of write failure when AutoClose is false.
Motivation:
As noticed in https://stackoverflow.com/questions/45700277/
compilation can fail if the definition of a method doesn't
match the declaration. It's easy enough to add this in, and make
it easy to compile.
Modifications:
Add JNIEXPORT to the entry points.
* On Windows this adds: `__declspec(dllexport)`
* On Mac this adds: `__attribute__((visibility("default")))`
* On Linux (GCC 4.2+) this adds: ` __attribute__((visibility("default")))`
* On other it doesn't add anything.
Result:
Easier compilation
Motivation:
KQueueEventLoop and EpollEventLoop implement different approaches to applying a timeout of their respective poll calls. Epoll attempts to ensure the desired timeout is satisfied at the java layer and at the JNI layer, but it should be sufficient to account for spurious wakups at the JNI layer. Epoll timeout granularity is also limited to milliseconds which may be too large for some latency sensitive applications.
Modifications:
- Make EpollEventLoop wait method look like KQueueEventLoop
- Epoll should support a finer timeout granularity via timerfd_create. We can hide most of these details behind the epollWait0 JNI call to avoid crossing additional JNI boundaries.
Result:
More consistent timeout approach between KQueue and Epoll.
Motivation:
The EPOLL transport uses EPOLLRDHUP to detect when the peer closes the write side of the socket. Currently KQueue is not able to mimic this behavior and the only way to detect if the peer has closed is to read. It may not always be appropriate to read for backpressure and other reasons at the application level.
Modifications:
- Support EVFILT_SOCK filter which provides notification when the peer closes the socket
Result:
KQueue transport has more consistent behavior with Epoll transport for detecting peer closure.
Motivation:
Due to an oversight (by myself), linking two JNI modules with
duplicate symbols fails in linking. This only seems to happen
some of the time (the behavior seems to be different between GCC
and Clang toolchains). For instance, including both netty tcnative
and netty epoll fails to link because of duplicate JNI_OnLoad
symobols.
Modification:
Do not define the JNI_OnLoad and JNI_OnUnload symbols when
compiling for static linkage, as indicated by the NETTY_BUILD_STATIC
preprocessor define. They are never directly called when
statically linked.
Result:
Able to statically compile epoll and tcnative code into a single
binary.
Motivation:
At the moment we try to load the library using multiple names which includes names using - but also _ . We should just use _ all the time.
Modifications:
Replace - with _
Result:
Fixes [#7069]
Motivation:
Implementations of DuplexChannel delegate the shutdownOutput to the underlying transport, but do not take any action on the ChannelOutboundBuffer. In the event of a write failure due to the underlying transport failing and application may attempt to shutdown the output and allow the read side the transport to finish and detect the close. However this may result in an issue where writes are failed, this generates a writability change, we continue to write more data, and this may lead to another writability change, and this loop may continue. Shutting down the output should fail all pending writes and not allow any future writes to avoid this scenario.
Modifications:
- Implementations of DuplexChannel should null out the ChannelOutboundBuffer and fail all pending writes
Result:
More controlled sequencing for shutting down the output side of a channel.
Motivation:
We did not correctly handle connect() and disconnect() in EpollDatagramChannel / KQueueDatagramChannel and so the behavior was different compared to NioDatagramChannel.
Modifications:
- Correct implement connect and disconnect methods
- Share connect and related code
- Add tests
Result:
EpollDatagramChannel / KQueueDatagramChannel also supports correctly connect() and disconnect() methods.
Motivation:
IP_TRANSPARENT support is not complete, the option can currently only be set on EpollServerSocket. Setting the option on an EpollSocket is also requires so as to be able to bind a socket to a non-local address as described in ip(7)
http://man7.org/linux/man-pages/man7/ip.7.html
"TProxy redirection with the iptables TPROXY target also
requires that this option be set on the redirected socket."
Modifications:
Added IP_TRANSPARENT socket option to EpollSocketChannelConfig
Result:
A redirecting socket can be created with a non-local IP address as required for TPROXY
Motivation:
We used an int[] to store all values that are returned in the struct for TCP_INFO which is not good enough as it uses usigned int values.
Modifications:
- Change int[] to long[] and correctly cast values.
Result:
No more truncated values.
Motivation:
`Epoll.ensureAvailability()` is called multiple times, once in
static initialization and in a couple of the constructors. This is
redundant and confusing to read.
Modifications:
Move `Epoll.ensureAvailability()` call into an instance initializer
and remove all other references. This ensures that every EELG
checks availability, while still delaying the check until
construction. This pattern is used when there are multiple ctors,
as in this class.
Result:
Easier to read code.
Motivation:
We should not try to detect a free port in tests put just use 0 when bind so there is no race in which the system my bind something to the port we choosen before.
Modifications:
- Remove the usage of TestUtils.getFreePort() in the testsuite
- Remove hack to workaround bind errors which will not happen anymore now
Result:
Less flacky tests.
Motivation:
When run the current testsuite on docker (mac) it will fail a few tests with:
io.netty.channel.AbstractChannel$AnnotatedConnectException: connect(..) failed: Cannot assign requested address: /0:0:0:0:0:0:0:0%0:46607
Caused by: java.net.ConnectException: connect(..) failed: Cannot assign requested address
Modifications:
Specify host explicit as done in other tests to only use ipv6 when really supported.
Result:
Build pass on docker as well
Motivation:
JCTools 2.0.2 provides an unbounded MPSC linked queue. Before we shaded JCTools we had our own unbounded MPSC linked queue and used it in various places but gave this up because there was no public equivalent available in JCTools at the time.
Modifications:
- Use JCTool's MPSC linked queue when no upper bound is specified
Result:
Fixes https://github.com/netty/netty/issues/5951
Motivation:
An intermediate list is creating in the `EpollEventLoop#closeAll` to prevent ConcurrentModificationException. But this is not the obvious purpose has no comment.
Modifications:
Add comment to clarify the appointment of the intermediate collection.
Result:
More clear code.
Motivation:
We used an intermediate collection to store the read DatagramPackets and only fired these through the pipeline once wewere done with the reading loop. This is not needed and can also increase memory usage.
Modifications:
Remove intermediate collection
Result:
Less overhead and possible less memory usage during read loop.
Motivation:
We had a typo in the method name of the EpollSocketChannelConfig.
Modifications:
Deprecate old method and introduce a new one.
Result:
Fixes [#6909]
Motivation:
Enable static linking for Java 8. These commits are the same as those introduced to netty tcnative. The goal is to allow lots of JNI libraries to be statically linked together without having conflict `JNI_OnLoad` methods.
Modification:
* add JNI_OnLoad suffixes to enable static linking
* Add static names to the list of libraries that try to be loaded
* Enable compiling with JNI 1.8
* Sort includes
Result:
Enable statically linked JNI code.
The code in question has this comment, but it is *after* the fall
so the static analysis flags it.
This is described in http://errorprone.info/bugpattern/FallThrough
Modifications:
Move fall through comment to where the fall actually occurs
Result:
More compatible with Error Prone tools
Motivation:
Google requires stricter compilation by adding -Werror and enabling many other warnings.
Modification:
* fix warning caused by -Wmissing-braces
* Use the address of `sendmmsg` rather than the function itself when
checking for presence. This resovles the warning caused by
`-Wpointer-bool-conversion`.
More detail:
When compiling on Linux, `sendmmsg` is always present, so the
function is always nonnull. When compiling elsewhere, the
function is defined as `__attribute__((weak))` which means it
may be absent at link time. This is controlled by
`IO_NETTY_SENDMMSG_NOT_FOUND`, which is off by default.
The reason for the error is due to the risk of accidentally not
calling the function. By adding `&` before the function, there
is no ambiguity. (the result of the fn call cannot have its
address taken.)
* use != to check for sendmmsg
Result:
Easier compilation.
