Motivation:
trackedObject != null gives no guarantee that trackedObject remains reachable. This may cause problems related to premature finalization: false leak detector warnings.
Modifications:
Add private method reachabilityFence0 that works on JDK 8 and can be factored out into PlatformDependent. Later, it can be swapped for the real Reference.reachabilityFence.
Result:
No false leak detector warnings in future versions of JDK.
Motivation:
DefaultResourceLeak.toString() did include the wrong value for duplicated records.
Modifications:
Include the correct value.
Result:
Correct toString() implementation.
Motivation:
Java since version 6 has the wrapper for the ConcurrentHashMap that could be created via Collections.newSetFromMap(map). So no need to create own ConcurrentSet class. Also, since netty plans to switch to Java 8 soon there is another method for that - ConcurrentHashMap.newKeySet().
For now, marking this class @deprecated would be enough, just to warn users who use netty's ConcurrentSet. After switching to Java 8 ConcurrentSet should be removed and replaced with ConcurrentHashMap.newKeySet().
Modification:
ConcurrentSet deprecated.
Motivation:
Seems like IntegerHolder counterHashCode field is the very old legacy field that is no longer used. Should be marked as deprecated and removed in the future versions.
Modification:
IntegerHolder class, InternalThreadLocalMap.counterHashCode() and InternalThreadLocalMap.setCounterHashCode(IntegerHolder counterHashCode) are now deprecated.
Motivation:
When a X509TrustManager is used while configure the SslContext the JDK automatically does some extra checks during validation of provided certs by the remote peer. We should do the same when our native implementation is used.
Modification:
- Automatically wrap a X509TrustManager and so do the same validations as the JDK does.
- Add unit tests.
Result:
More consistent behaviour. Fixes https://github.com/netty/netty/issues/6664.
Motivation:
The Epoll transport checks to see if there are any scheduled tasks
before entering epoll_wait, and resets the timerfd just before.
This causes an extra syscall to timerfd_settime before doing any
actual work. When scheduled tasks aren't added frequently, or
tasks are added with later deadlines, this is unnecessary.
Modification:
Check the *deadline* of the peeked task in EpollEventLoop, rather
than the *delay*. If it hasn't changed since last time, don't
re-arm the timer
Result:
About 2us faster on gRPC RTT 50pct latency benchmarks.
Before (2 runs for 5 minutes, 1 minute of warmup):
```
50.0%ile Latency (in nanos): 64267
90.0%ile Latency (in nanos): 72851
95.0%ile Latency (in nanos): 78903
99.0%ile Latency (in nanos): 92327
99.9%ile Latency (in nanos): 119691
100.0%ile Latency (in nanos): 13347327
QPS: 14933
50.0%ile Latency (in nanos): 63907
90.0%ile Latency (in nanos): 73055
95.0%ile Latency (in nanos): 79443
99.0%ile Latency (in nanos): 93739
99.9%ile Latency (in nanos): 123583
100.0%ile Latency (in nanos): 14028287
QPS: 14936
```
After:
```
50.0%ile Latency (in nanos): 62123
90.0%ile Latency (in nanos): 70795
95.0%ile Latency (in nanos): 76895
99.0%ile Latency (in nanos): 90887
99.9%ile Latency (in nanos): 117819
100.0%ile Latency (in nanos): 14126591
QPS: 15387
50.0%ile Latency (in nanos): 61021
90.0%ile Latency (in nanos): 70311
95.0%ile Latency (in nanos): 76687
99.0%ile Latency (in nanos): 90887
99.9%ile Latency (in nanos): 119527
100.0%ile Latency (in nanos): 6351615
QPS: 15571
```
* Log the correct line-number when using SLF4j with netty if possible.
Motivation:
At the moment we do not log the correct line number in many cases as it will log the line number of the logger wrapper itself. Slf4j does have an extra interface that can be used to filter out these nad make it more usable with logging wrappers.
Modifications:
Detect if the returned logger implements LocationAwareLogger and if so make use of its extra methods to be able to log the correct origin of the log request.
Result:
Better logging when using slf4j.
Motivation:
In Java8 and earlier we used reflection to replace the used key set if not otherwise told. This does not work on Java9 and later without special flags as its not possible to call setAccessible(true) on the Field anymore.
Modifications:
- Use Unsafe to instrument the Selector with out special set when sun.misc.Unsafe is present and we are using Java9+.
Result:
NIO transport produce less GC on Java9 and later as well.
Motivation:
In Java8 and earlier we used reflection to detect if unaligned access is supported. This fails in Java9 and later as we would need to change the accessible level of the method.
Lucky enough we can use Unsafe directly to read the content of the static field here.
Modifications:
Add special handling for detecting if unaligned access is supported on Java9 and later which does not fail due jigsaw.
Result:
Better and more correct detection on Java9 and later.
Motivation:
At the moment we will just assume the correct version of log4j2 is used when we find it on the classpath. This may lead to an AbstractMethodError at runtime. We should not use log4j2 if the version is not correct.
Modifications:
Check on class loading if we can use Log4J2 or not.
Result:
Fixes#8217.
Motivation:
Log4J2Logger had some code-duplication with AbstractInternalLogger
Modifications:
Reuse AbstractInternaLogger.EXCEPTION_MESSAGE in Log4J2Logger and so remove some code-duplication
Result:
Less duplicated code.
* We should be able to use the ByteBuffer cleaner on java8 (and earlier versions) even if sun.misc.Unsafe is not present.
Motivation:
At the moment we have a hard dependency on sun.misc.Unsafe to use the Cleaner on Java8 and earlier. This is not really needed as we can still use pure reflection if sun.misc.Unsafe is not present.
Modifications:
Refactor Cleaner6 to fallback to pure reflection if sun.misc.Unsafe is not present on system.
Result:
More timely releasing of direct memory on Java8 and earlier when sun.misc.Unsafe is not present.
Motivation:
f77891cc17 changed slightly how we detect if we should prefer direct buffers or not but did miss to also take this into account when logging.
Modifications:
Fix branch for log message to reflect changes in f77891cc17.
Result:
Correct logging.
Motivation:
There was a race condition between the task submitter and task executor threads such that the last Runnable submitted may not get executed.
Modifications:
The bug was fixed by checking the task queue and state in the task executor thread after it saw the task queue was empty.
Result:
Fixes#8230
Motivation:
We should prefer direct buffers whenever we can use the cleaner even if sun.misc.Unsafe is not present.
Modifications:
Correctly prefer direct buffers in all cases.
Result:
More correct code.
Motivation:
CleanerJava9 currently fails whever a SecurityManager is installed. We should make use of AccessController.doPrivileged(...) so the user can give it the correct rights.
Modifications:
Use doPrivileged(...) when needed.
Result:
Fixes https://github.com/netty/netty/issues/8201.
Motivation:
Recycler may produce a NPE when the same object is recycled multiple times from different threads.
Modifications:
- Check if the id has changed or if the Stack became null and if so throw an IllegalStateException
- Add unit test
Result:
Fixes https://github.com/netty/netty/issues/8220.
* Try to monkey-patch library id when shading is used and we are on MacOS / OSX.
Motivation:
ea4c315b45 did ensure we support using multiple versions of the same shaded native library but the user still needed to run install_name_tool -id on MacOS to ensure the ID is unique.
This is kind of error prone and also means that the shading itself would need to be done on MacOS / OSX.
This is related to https://github.com/netty/netty/issues/7272.
Modifications:
- Monkey patch the shaded native lib on MacOS to ensure the id is unique while unpacking it to the tempory location.
Result:
Easier way of using shaded native libs in netty.
Motivation:
Java9 and later does the safepoint polling by itself so there is not need for us to do it.
Modifications:
Check for java version before doing manual safepoint polling.
Result:
Less custom code and less overhead when using java9 and later. Fixes https://github.com/netty/netty/issues/8122.
Motivation:
We do not correctly check for previous calles of setUncancellable() in getNow() which may result in ClassCastException as we incorrectly return the internally UNCANCELLABLE object and not null if setUncancellable() we as called before.
Modifications:
Correctly check for UNCANCELLABLE and add unit test.
Result:
Fixes https://github.com/netty/netty/issues/8135.
Motivation:
We incorrectly calculated the length that was used for our for loop in AsciiString.indexOf(...). This lead to a possible ArrayIndexOutOfBoundsException.
Modifications:
- Not include the start in the length calculation
- Add unit test.
Result:
Fixes https://github.com/netty/netty/issues/8112.
Motivation:
Users should not see a scary log message when Netty is initialized if
Netty configuration explicitly disables unsafe. The log message that
produces this warning was previously guarded but by recent refactoring
a bug was introduced inside the guard helper method.
Modifications:
This commit brings back the guard against the scary log message if
unsafe is explicitly disabled.
Result:
No log message is produced when unsafe is unavailable because Netty was
told to not look for it.
Relates https://github.com/netty/netty/pull/5624, https://github.com/netty/netty/pull/6696
Motivation:
ObjectCleaner does start a Thread to handle the cleaning of resources which leaks into the users application. We should not use it in netty itself to make things more predictable.
Modifications:
- Remove usage of ObjectCleaner and use finalize as a replacement when possible.
- Clarify javadocs for FastThreadLocal.onRemoval(...) to ensure its clear that remove() is not guaranteed to be called when the Thread completees and so this method is not enough to guarantee cleanup for this case.
Result:
Fixes https://github.com/netty/netty/issues/8017.
Motivation:
I'm not sure if trivial changes like this are interesting :-) But I
noticed that the PlatformDependent.maxDirectMemory0() method is called
twice unnecessarily during static initialization (on the default path at
least).
Modifications:
Use constant MAX_DIRECT_MEMORY already set to the same value instead of
calling maxDirectMemory0() again.
Result:
A surely imperceivable reduction in operations performed at startup.
Motivation
There is a cost to concatenating strings and calling methods that will be wasted if the Logger's level is not enabled.
Modifications
Check if Log level is enabled before producing log statement. These are just a few cases found by RegEx'ing in the code.
Result
Tiny bit more efficient code.
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.
Motivation:
On J9 / OpenJ9 netty initializes this value with 64M, even the direct accessible memory is actually unbounded.
Modifications:
Skip usage of VM.maxDirectMemory() on J9 / OpenJ9
Result:
More correct direct memory limit detection. Fixes#7654.
Motivation:
We did not guard against the case of calling malloc(0) when creating a ByteBuffer without a Cleaner. The problem is that malloc(0) can have different behaviour, it either return a null-pointer or a valid pointer that you can pass to free.
The real problem arise if Unsafe.allocateMemory(0) returns 0 and we use it as the memoryAddress of the ByteBuffer. The problem here is that native libraries test for 0 and handle it as a null-ptr. This is for example true in SSL.bioSetByteBuffer(...) which would throw a NPE when 0 is used as memoryAddress and so produced errors during SSL usage.
Modifications:
- Always allocate 1 byte as minimum (even if we ask for an empty buffer).
- Add unit test.
Result:
No more errors possible because of malloc(0).
Motivation:
When a buffer is over-released, the current error message of `IllegalReferenceCountException` is `refCnt: XXX, increment: XXX`, which is confusing. The correct message should be `refCnt: XXX, decrement: XXX`.
Modifications:
Pass `-decrement` to create `IllegalReferenceCountException`.
Result:
The error message will be `refCnt: XXX, decrement: XXX` when a buffer is over-released.
Motivation:
On z/OS netty initializes this value with 64M, even the direct accessible memory is actually unbounded.
Modifications:
Skip usage of VM.maxDirectMemory() on z/OS.
Result:
More correct direct memory limit detection. Fixes https://github.com/netty/netty/issues/7654.
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:
A FastThreadLocal instance currently occupies 2 slots of InternalThreadLocalMap of every thread. Actually for a FastThreadLocalThread, it does not need to store cleaner flags of FastThreadLocal instances. Besides, using BitSet to store cleaner flags is also better for space usage.
Modification:
Use BitSet to optimize space usage of FastThreadLocal.
Result:
Avoid unnecessary slot occupancy. Cleaner flags are now stored into a BitSet.
Motivation:
When trying to cleanup WeakOrderQueue by the ObjectCleaner we end up in an endless loop which will cause the ObjectCleaner to be not able to cleanup any other resources anymore.This bug was introduced by 6eb9674bf5.
Modifications:
Correctly update link while cleanup
Result:
Fixes https://github.com/netty/netty/issues/7877
Motivation:
The bounds checking for AsciiString#indexOf and AsciiString#lastIndexOf is not correct and may lead to ArrayIndexOutOfBoundsException.
Modifications:
- Correct the bounds checking for AsciiString#indexOf and AsciiString#lastIndexOf
Result
Fixes https://github.com/netty/netty/issues/7863
Motivation:
Finer granularity when configuring CorsHandler, enabling different policies for different origins.
Modifications:
The CorsHandler has an extra constructor that accepts a List<CorsConfig> that are evaluated sequentially when processing a Cors request
Result:
The changes don't break backwards compatibility. The extra ctor can be used to provide more than one CorsConfig object.
Motivation:
Minor performance optimisation that prevents thread from blocking due to task not having been added to queue. Discussed #7815.
Modification:
add task to the queue before starting the thread.
Result:
No additional tests.
* NetUtil valid IP methods to accept CharSequence
Motivation:
NetUtil has methods to determine if a String is a valid IP address. These methods don't rely upon String specific methods and can use CharSequence instead.
Modifications:
- Use CharSequence instead of String for the IP validator methods.
- Avoid object allocation in AsciiString#indexOf(char,int) and reduce
byte code
Result:
No more copy operation required if a CharSequence exists.
Motivation:
HttpProxyHandler uses `NetUtil#toSocketAddressString` to compute
CONNECT url and Host header.
The url is correct when the address is unresolved, as
`NetUtil#toSocketAddressString` will then use
`getHoststring`/`getHostname`. If the address is already resolved, the
url will be based on the IP instead of the hostname.
There’s an additional minor issue with the Host header: default port
443 should be omitted.
Modifications:
* Introduce NetUtil#getHostname
* Introduce HttpUtil#formatHostnameForHttp to format an
InetSocketAddress to
HTTP format
* Change url computation to favor hostname instead of IP
* Introduce HttpProxyHandler ignoreDefaultPortsInConnectHostHeader
parameter to ignore 80 and 443 ports in Host header
Result:
HttpProxyHandler performs properly when connecting to a resolved address
Motivation:
We missed to correctly record the stacktrace of the creation of an ResourceLeak record. This could either have the effect to log the wrote stacktrace for creation or not log a stacktrace at all if the object was dropped on the floor after it was created.
Modifications:
Correctly create a Record on creation of the object.
Result:
Fixes https://github.com/netty/netty/issues/7781.
Motivation:
We recently introduced ObjectCleaner which can be used to ensure some cleanup action is done once an object becomes weakable reachable. We should use this in Recycler.WeakOrderQueue to reduce the overhead of using a finalizer() (which will cause the GC to process it two times).
Modifications:
Replace finalizer() usage with ObjectCleaner
Result:
Fixes [#7343]
Motivation:
We dont protect from overflow and so the timer may fire too early if a large timeout is used.
Modifications:
Add overflow guard and a test.
Result:
Fixes https://github.com/netty/netty/issues/7760.
Motivation:
It is not clear why Unsafe is unavailable when it is explicitly
disabled, or when Netty thinks it is running on Android.
Modification:
Change the "has" fields and methods to be causes. A null cause
means Unsafe is present. This catches all possible reason why
Unsafe might not be available.
Result:
Easier to debug Netty start up when logging cannot be turned on.
Motivation:
DefaultPromise's internal state depends upon specific Signal objects. These Signal objects can be used externally which causes the DefaultPromise object API to not function correct and state to become corrupted.
Modifications:
- DefaultPromise shouldn't depend upon Signal for its internal state
Result:
Fixes https://github.com/netty/netty/issues/7707
Motivation:
The Recycler currently retains 32k objects per thread by default. The Recycler is used in more than just one place and may result in large amounts of memory bloat if spikes of traffic are observed.
Modifications:
- Reduce the Recyclers default capacity from 32k to 4k.
Result:
- Lower default capacity of the Recycler and less memory retained.
Motivation:
Some java binaries include android classes on their classpath, even
if they aren't actually android. When this is true, `Unsafe` no
longer works, disabling the Epoll functionality. A sample case is
for binaries that use the j2objc library.
Modifications:
Check the `java.vm.name` instead of the classpath. Numerous
Google-internal Android libraries / binaries check this property
rather than the class path.
It is believed this is safe and works with bother ART and Dalvik
VMs, safe for Robolectric, and j2objc.
Results:
Unusually built java server binaries can still use Netty Epoll.
