java - 在 main() 中设置系统资源限制时，Java JNA 应用程序崩溃

Question

我有一个 JNA 应用程序需要计算大型一维数组 (~1G) 中的元素总和。使用 JNA Resource.Rlimit 类，我可以增加资源限制，如以下代码段所示：

final Resource.Rlimit limit = new Resource.Rlimit();      
limit.rlim_cur = 1024L * 1024L * 1024L;
limit.rlim_max = 2 * 1024L * 1024L * 1024L;

但是，这只适用于在分配大数组的方法中设置堆栈大小的情况。因此，当我运行以下代码时，没有内存不足异常。

package com.jnaapps;

import com.sun.jna.Library;
import com.sun.jna.Pointer;
import com.sun.jna.Native;
import com.sun.jna.Memory;
import com.sun.jna.platform.unix.LibCAPI;
import com.sun.jna.platform.unix.Resource;

public class Main {
    public interface CLibrary extends LibCAPI, Library {
        CLibrary INSTANCE = (CLibrary) Native.load("c", CLibrary.class);
    }

    public interface NativeClass extends Library {
        NativeClass INSTANCE = (NativeClass)Native.load("nativemethods", NativeClass.class);

        double sumOfArray1d(final Pointer values, long numberOfValues);
    }

    public static void main(String[] args) {
        Test0();
    }


    public static void Test0() {
        final Resource.Rlimit limit = new Resource.Rlimit();
        limit.rlim_cur = 1024L * 1024L * 1024L;
        limit.rlim_max = 2 * 1024L * 1024L * 1024L;

        int err = CLibrary.INSTANCE.setrlimit(Resource.RLIMIT_STACK, limit);
        if (err != 0) {
            int lastError = Native.getLastError();
            System.out.println("An exception occurred while setting RLimit: " +
                    lastError);
        }

        NativeClass clib = NativeClass.INSTANCE;

        long dim = 10000L * 10000L;

        final Pointer bigVector = new Memory(dim*Native.getNativeSize(Double.TYPE));

        for (long i=0; i<dim; ++i) {
            bigVector.setDouble(i*Native.getNativeSize(Double.TYPE), 3.5e-6);
        }

        double total = clib.sumOfArray1d(bigVector, dim);

        System.out.println("Sum of elements in big vector = " + total);
    }

    public static void Test1() {
        NativeClass clib = NativeClass.INSTANCE;

        long dim = 10000L * 10000L;

        final Pointer bigVector = new Memory(dim*Native.getNativeSize(Double.TYPE));

        for (long i=0; i<dim; ++i) {
            bigVector.setDouble(i*Native.getNativeSize(Double.TYPE), 3.5e-6);
        }

        double total = clib.sumOfArray1d(bigVector, dim);

        System.out.println("Sum of elements in big vector = " + total);
    }
}

但是，当在 main() 中设置资源限制并调用方法 Test1() 时，程序会崩溃。

public static void main(String[] args) {
    final Resource.Rlimit limit = new Resource.Rlimit();
    limit.rlim_cur = 1024L * 1024L * 1024L;
    limit.rlim_max = 2 * 1024L * 1024L * 1024L;

    int err = CLibrary.INSTANCE.setrlimit(Resource.RLIMIT_STACK, limit);
    if (err != 0) {
        int lastError = Native.getLastError();
        System.out.println("An exception occurred while setting RLimit: " +
                    lastError);
    }

    Test1();
}

为什么我不能在调用 Test1() 之前增加 main() 中的堆栈大小。该项目是在具有 8GB RAM 的 Ubuntu 16.04 amdx86-64 上使用 IntelliJ Idea（社区版本 2019.3）编写的。

标签： javastackjava-native-interfacejnasetrlimit