创建<100个线程时的Java`OutOfMemoryError`

Question

由于这个错误,我一直在阅读和测试并在墙上撞了一天多一天.

我在类中有一些Java代码Listener,看起来像这样

ExecutorService executor = Executors.newFixedThreadPool(NTHREADS);
boolean listening = true;
int count = 0;
while (listening) {
    Runnable worker;
    try {
        worker = new ServerThread(serverSocket.accept()); // this is line 254
        executor.execute(worker);
        count++;
        logger.info("{} threads started", count);
    } catch (Exception e1){
        //...
    }
}

我一直在调整JVM设置-Xmx(从1到15G -Xss不等)和(从104k到512M).服务器有24 GB的RAM,但还必须运行支持该程序的数据库.

在创建了2-20个线程之后(程序中的其他地方也存在了几十个),我得到了错误

Exception in thread "Thread-0" java.lang.OutOfMemoryError: unable to create new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Thread.java:657)
at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:943)
at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1325)
at xxx.Listener.run(Listener.java:254)

$java -version 收益率:

java version "1.6.0_24"
OpenJDK Runtime Environment (IcedTea6 1.11.1) (fedora-65.1.11.1.fc16-x86_64)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)

发生这种情况时,系统上总是有大量可用内存,其他程序继续执行正常.是什么导致Java认为它没有新线程的内存？

更新: 也许这比我想象的要大 - 我使用时设法得到这个错误(只有一次)^C:

OpenJDK 64-Bit Server VM warning: Exception java.lang.OutOfMemoryError occurred dispatching signal SIGINT to handler- the VM may need to be forcibly terminated

当我试图杀死客户端时也发生了同样的事情(也是用Java编写并在同一台服务器上运行,它是一个读取文件并通过套接字将其发送到服务器的线程),所以绝对有限制JVM导致一个人干扰另一个,但我无法想象如果我还有空闲内存并且根本不使用交换？服务器-Xmx1G -Xss104k客户端-Xmx10M

UPDATE2: 放弃perl Forks::Super库并从bash运行客户端让我在服务器与OOME崩溃之前最多可以运行34个线程,因此运行多个客户端肯定会对服务器产生影响,但同时我仍然可以运行一次超过34个(68个,如果一个计算客户端)java线程.哪些系统资源阻止了更多线程的创建(即我应该在哪里寻找生猪)？当所有内容(客户端,服务器,GC ...)同时耗尽内存时,请top说明我的CPU和内存使用情况:

Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  24681040k total,  1029420k used, 23651620k free,    30648k buffers
Swap: 26836988k total,        0k used, 26836988k free,   453620k cached

UPDATE3:下面的hs_error日志是否表明我的java不是64位？

# 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.
#
# JRE version: 6.0_24-b24
# Java VM: OpenJDK 64-Bit Server VM (20.0-b12 mixed mode linux-amd64 compressed oops)
# Derivative: IcedTea6 1.11.1
# Distribution: Fedora release 16 (Verne), package fedora-65.1.11.1.fc16-x86_64

Answer 1

您可以限制max user processes,了解您的限制使用:

ulimit -u

要更改限制:

在/etc/security/limits.conf集合中:

user soft nproc [your_val] 
user hard nproc [your_val]

如果查看此链接不够,您可能需要添加其他配置.

注意:OP 在fedora和centos中发现了这个错误报告,解释了编辑的局限性/etc/security/limits.conf.