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[#2623] Release local references to guard against StackOverflow in JNI

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Motivation:

When we do a (env*)->GetObjectArrayElement(...) call we may created many local references which will only be cleaned up once we exist the native method. Thus a lot of memory can be used and so a StackOverFlow may be triggered. Beside this the JNI specification only say that an implementation must cope with 16 local references.

Modification:

Call (env*)->ReleaseLocalRef(...) to release the resource once not needed anymore.

Result:

Less memory usage and guard against StackOverflow
This commit is contained in:
Norman Maurer 2014-06-30 09:22:58 +02:00
parent 9594a81b95
commit 23840b76d7
1 changed files with 17 additions and 0 deletions
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17
transport-native-epoll/src/main/c/io_netty_channel_epoll_Native.c
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@ -740,6 +740,12 @@ JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writev(JNIEnv * env,
iov[iovidx].iov_base = buffer + pos;
iov[iovidx].iov_len = (size_t) (limit - pos);
iovidx++;
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
jlong res = writev0(env, clazz, fd, iov, length);
if (res <= 0) {
@ -759,6 +765,11 @@ JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writev(JNIEnv * env,
incrementPosition(env, bufObj, len);
written -= len;
}
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
return res;
}
@ -776,6 +787,12 @@ JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writevAddresses(JNIEn
iov[iovidx].iov_base = memoryAddress + readerIndex;
iov[iovidx].iov_len = (size_t) (writerIndex - readerIndex);
iovidx++;
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, addressEntry);
}
jlong res = writev0(env, clazz, fd, iov, length);