为什么Java中的堆会发生变化 [英] Why the heap is changing in java

问题描述

例如，我们以-Xms等于-Xmx valuem来启动Java进程:

-Xms1500m -Xmx1500m -Dos.heap.max=1500m -verbose:gc -XX:MaxPermSize=256m 

由于某种原因，堆在运行时发生了变化...:

[GC 624542K->464935K(1472000K), 0.0647450 secs] Wed Jul 3 15:58:23 2013
[GC 808811K->813332K(1472000K), 0.1407890 secs] Wed Jul 3 15:58:23 2013
[Full GC 813332K->636599K(1472000K), 0.7913590 secs] Wed Jul 3 15:58:24 2013
[GC 1016090K->956043K(1258752K), 0.1209670 secs] Wed Jul 3 15:58:24 2013
[Full GC 956043K->955974K(1258752K), 0.4132560 secs] Wed Jul 3 15:58:25 2013
[Full GC 1126726K->1122269K(1258752K), 0.4376340 secs] Wed Jul 3 15:58:25 2013
[Full GC 1126726K->1115353K(1258752K), 0.8102960 secs] Wed Jul 3 15:58:26 2013

问题是为什么堆内存在运行时正在改变...?

解决方案

我理解的问题是，即使初始大小设置为1500m，为什么堆大小也从1500m(1472000K)减小到较小的值(1258752K). >

事实证明，这是长时间运行的JVM中的众所周知的行为，并且与PS MarkSweep/完整GC机制有关-请参见 解决方案

I understand the question to be why the heap size drops from 1500m (1472000K) to something less (1258752K) even though initial size is set to 1500m.

As it turns out, this is well known behavior in long running JVMs, and is related to the PS MarkSweep / Full GC mechanism - See this article for a good writeup.

Cheers,

这篇关于为什么Java中的堆会发生变化的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！