Linux 上的 Java 内存不足，即使有足够的可用内存用于缓存

Question

我正在尝试在 Red Hat Enterprise Linux Server 6.5 (Santiago) 版上启动一个进程，该进程失败了，因为它无法分配足够的内存。

# There is insufficient memory for the Java Runtime Environment to continue. 
# Cannot create GC thread. Out of system resources.
# An error report file with more information is saved as:

问题不在于 Java 应用程序本身 - 当我简单地运行时，我也会收到错误：

版本

查看内存消耗：

自由 -m

             total       used       free     shared    buffers     cached
Mem:         32069      31276        792          0        556      16948
-/+ buffers/cache:      13771      18297
Swap:         9325         38       9287

因此，Mem 报告说正在使用 32 Gb 内存中的 31 Gb，但应该有 18 Gb 可用内存由缓存使用。当进程请求内存时，操作系统不应该释放其中的一些吗？

错误转储的详细信息是

#
# There is insufficient memory for the Java Runtime Environment to continue.
# Cannot create GC thread. Out of system resources.
# Possible reasons:
#   The system is out of physical RAM or swap space
#   In 32 bit mode, the process size limit was hit
# Possible solutions:
#   Reduce memory load on the system
#   Increase physical memory or swap space
#   Check if swap backing store is full
#   Use 64 bit Java on a 64 bit OS
#   Decrease Java heap size (-Xmx/-Xms)
#   Decrease number of Java threads
#   Decrease Java thread stack sizes (-Xss)
#   Set larger code cache with -XX:ReservedCodeCacheSize=
# This output file may be truncated or incomplete.
#
#  Out of Memory Error (gcTaskThread.cpp:46), pid=40816, tid=140071992215296
#
# JRE version: 6.0_26-b03
# Java VM: Java HotSpot(TM) 64-Bit Server VM (20.1-b02 mixed mode linux-amd64 compressed oops)

---------------  T H R E A D  ---------------

Current thread (0x00007f6508006800):  JavaThread "Unknown thread" [_thread_in_vm, id=40817,              stack(0x00007f650d46c000,0x00007f650d56d000)]

Stack: [0x00007f650d46c000,0x00007f650d56d000],  sp=0x00007f650d56b7c0,  free space=1021k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x85ebd5]  VMError::report_and_die()+0x265
V  [libjvm.so+0x3e41b8]  report_vm_out_of_memory(char const*, int, unsigned long, char const*)+0x68
V  [libjvm.so+0x466ada]  GCTaskThread::GCTaskThread(GCTaskManager*, unsigned, unsigned)+0x13a
V  [libjvm.so+0x4655de]  GCTaskManager::initialize()+0x21e
V  [libjvm.so+0x465373]  GCTaskManager::GCTaskManager(unsigned)+0x13
V  [libjvm.so+0x722cad]  ParallelScavengeHeap::initialize()+0x4dd
V  [libjvm.so+0x836549]  Universe::initialize_heap()+0xa9
V  [libjvm.so+0x8360ea]  universe_init()+0x7a
V  [libjvm.so+0x4ac53b]  init_globals()+0x4b
V  [libjvm.so+0x81cc74]  Threads::create_vm(JavaVMInitArgs*, bool*)+0x214
V  [libjvm.so+0x51a7b0]  JNI_CreateJavaVM+0x80

Answer 1

查看 jvm 最小最大内存，您使用任何 Web 服务器吗？查看线程数、内存设置——对于 Tomcat，大多数都是 @server.xml。查看 Java Mission Control http://www.oracle.com/technetwork/java/javaseproducts/mission-control/java-mission-control-1998576.html以获得额外的见解。Linux 通常会保留更多内存以供请求时使用。对于 Linux 上的 Java，只有像 JMC 这样的东西可以帮助您了解正在发生的事情。查看 JVM 的标准输出。