使用malloc的内存泄漏失败 [英] Memory Leak Using malloc fails

问题描述

我正在向泄漏内存(主内存)编写一个程序，以测试系统在低系统内存和交换内存的情况下的行为.我们正在使用以下循环，该循环定期运行并泄漏内存

main(int argc, char* argv[] )  
{
   int arg_mem = argv[1];

        while(1)
        {
          u_int_ptr =(unsigned int*)  malloc(arg_mem * 1024 * 1024);

        if( u_int_ptr == NULL )
           printf("\n leakyapp Daemon FAILED due to insufficient available memory....");

          sleep( arg_time );
        }

}

以上循环运行一段时间，并显示消息由于可用内存不足，导致leakyapp守护程序失败...".但是，当我运行命令"free"时，我可以看到运行该程序对主存或交换都没有影响.

我做错什么了吗?

解决方案

物理内存只有在您实际写入内存后才会提交给您.

如果内核版本为2.6.23之后，请使用带有MAP_POPULATE标志而不是malloc()的mmap():

u_int_ptr = mmap(NULL, arg_mem * 1024 * 1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);

if (u_int_ptr == MAP_FAILED)
    /* ... */

如果您的内核较旧，则必须触摸分配中的每个页面.

I am writing a program to leak memory( main memory ) to test how the system behaves with low system memory and swap memory. We are using the following loop which runs periodically and leaks memory

main(int argc, char* argv[] )  
{
   int arg_mem = argv[1];

        while(1)
        {
          u_int_ptr =(unsigned int*)  malloc(arg_mem * 1024 * 1024);

        if( u_int_ptr == NULL )
           printf("\n leakyapp Daemon FAILED due to insufficient available memory....");

          sleep( arg_time );
        }

}

Above loop runs for sometime and prints the message "leakyapp Daemon FAILED due to insufficient available memory...." . But when I run the command "free" I can see that running this program has no effect either on Main memory or Swap.

Am I doing something wrong ?

解决方案

Physical memory is not committed to your allocations until you actually write into it.

If you have a kernel version after 2.6.23, use mmap() with the MAP_POPULATE flag instead of malloc():

u_int_ptr = mmap(NULL, arg_mem * 1024 * 1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);

if (u_int_ptr == MAP_FAILED)
    /* ... */

If you have an older kernel, you'll have to touch each page in the allocation.

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