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JNI代码IE与垃圾收集同时执行。

java-native-interface jvm garbage-collection

2

Gilgamesz · 技术社区 · 7 年前

它写在 http://psy-lob-saw.blogspot.com/2015/12/safepoints.html

Java线程在执行JNI代码时处于安全点。以前跨越本机调用边界,堆栈保持一致在移交给本机代码之前状态。这意味着线程仍可以在安全点运行。

怎么可能?毕竟,我可以将对象的引用传递给 JNI . 在JNI中,我可以在该对象中设置字段。

很明显,它不能被收集(我们有一个本地参考)。但是,它可以在完全GC收集期间通过GC移到旧一代。因此,我们有以下情况:

GC collector:                          | Thread executing JNI code
compact old generation                 | modify object fields that can be 
and move object from young generation  | moved now! A catastrophe. 
to old generation.                     |

JVM是如何处理的?

1 回复 | 直到 7 年前

1

4

apangin 7 年前

in_native in_vm

ThreadStateTransition::transition_from_native() JavaThread::check_safepoint_and_suspend_for_native_trans(thread)

// Slow path when the native==>VM/Java barriers detect a safepoint is in
// progress or when _suspend_flags is non-zero.
// Current thread needs to self-suspend if there is a suspend request and/or
// block if a safepoint is in progress.