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我目前正在研究一次加载和转换多个图像的管道。由于许多图像同时发生这种情况（1440），因此内存占用非常大。因此，我尝试实现基于 setrlimit 的内存管理系统，但是它似乎不会影响生成的线程（std::thread），因为它们会很高兴地忽略限制 - 我知道这是因为在线程函数 - 并最终导致我的程序被杀死。这是我用于设置限制的代码：

void setMemoryLimit(std::uint64_t bytes)
{
    struct rlimit limit;
    getrlimit(RLIMIT_AS, &limit);

    if(bytes <= limit.rlim_max)
    {
        limit.rlim_cur = bytes;
        std::cout << "New memory limit: " << limit.rlim_cur << " bytes" << std::endl;
    }
    else
    {
        limit.rlim_cur = limit.rlim_max;
        std::cout << "WARNING: Memory limit couldn't be set to " << bytes << " bytes" << std::endl;
        std::cout << "New memory limit: " << limit.rlim_cur << " bytes" << std::endl;
    }

    if(setrlimit(RLIMIT_AS, &limit) != 0)
        std::perror("WARNING: memory limit couldn't be set:");

    // included for debugging purposes
    struct rlimit tmp;
    getrlimit(RLIMIT_AS, &tmp);
    std::cout << "Tmp limit: " << tmp.rlim_cur << " bytes" << std::endl; // prints the correct limit
}

我正在使用 Linux。手册页指出 setrlimit 会影响整个过程，所以我有点不知道为什么线程似乎没有受到影响。

编辑：顺便说一下，上面的函数是在 main() 的最开始调用的。

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1 回答 1

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The problem was quite hard to find as it consisted of two entirely independent components:

  1. My executable was compiled with -fomit-frame-pointer. This will result in a reset of the limit. See the following example:

    /* rlimit.cpp */
#include <iostream>
#include <thread>
#include <vector>

#include <sys/resource.h>

class A
{
    public:
        void foo()
        {
            struct rlimit limit;
            getrlimit(RLIMIT_AS, &limit);
            std::cout << "Limit: " << limit.rlim_cur << std::endl;
        }
};

int main()
{
    struct rlimit limit;
    limit.rlim_cur = 500 * 1024 * 1024;
    setrlimit(RLIMIT_AS, &limit);
    std::cout << "Limit: " << limit.rlim_cur << std::endl;

    std::vector<std::thread> t;

    for(int i = 0; i < 5; i++)
    {
        A a;
        t.push_back(std::thread(&A::foo, &a));
    }

    for(auto thread : t)
        thread.join();

    return 0;
}

    Outputs:

    > g++ -std=c++11 -pthread -fomit-frame-pointer rlimit.cpp -o limit
> ./limit
Limit: 524288000
Limit: 18446744073709551615
Limit: 18446744073709551615
Limit: 18446744073709551615
Limit: 18446744073709551615
Limit: 18446744073709551615

> g++ -std=c++11 -pthread rlimit.cpp -o limit
> ./limit
Limit: 524288000
Limit: 524288000
Limit: 524288000
Limit: 524288000
Limit: 524288000
Limit: 524288000

  2. For the image processing part I work with OpenCL. Apparently NVIDIA's implementation calls setrlimit and pushes the limit to rlim_max.

于 2014-05-12T13:38:32.863 回答