具有-Xmx1024m的Java进程如何占用3GB的驻留内存? [英] How can a Java process with -Xmx1024m occupy 3GB resident memory?

问题描述

这是Websphere6.1，Solaris 10，JDK 1.5.0_13上的Java Web应用程序.我们将最大堆大小设置为1024m. jmap显示堆状态正常.堆内存使用率仅为57％.根本没有内存不足.

It's a Java web application on Websphere6.1, Solaris 10, JDK 1.5.0_13. We set the maximum heap size to 1024m. jmap shows the heap status is healthy. The heap memory usage is only 57%. No OutOfMemory at all.

但是我们从ps看到了用于此Java进程的非常高的RSS(3GB). pmap显示了一块1.9G的专用内存.

But we saw very high RSS (3GB) for this java process from ps. pmap shows a block of 1.9G private memory.

3785:   /dmwdkpmmkg/was/610/java/bin/java -server -Dwas.status.socket=65370 -X
 Address  Kbytes     RSS    Anon  Locked Pgsz Mode   Mapped File
...
0020A000    2008    2008    2008       -   8K rwx--    [ heap ]
00400000 1957888 1957888 1957888       -   4M rwx--    [ heap ]
8D076000      40      40      40       -   8K rw--R    [ stack tid=10786 ]
...

在本机代码中是否发生了C堆内存泄漏?建议使用哪种方法找出根本原因?

Is it a C heap memory leak in native code? What approach is recommended to find out the root cause?

推荐答案

此

This Troubleshooting Memory Leaks document from Sun may help you with finding the problem why your high RSS, specially in section 3.4.

在运行Websphere时，也许可以在VM上使用 -memorycheck .有关详细信息，请参见此处.

As you are running Websphere, maybe you can use the -memorycheck on your VM. For details see here.

不一定是本机代码泄漏.如果您在Solaris上此处，则文件可能存在问题保持开放状态.

It's not necessarily a leak in native code. If you look here, on Solaris there might be an issue with files being kept open.

这只是一堆链接和提示，但可能有助于您找出问题所在.

It's just a bunch of links and hints, but maybe helpful to track down your problem.

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