“私有字节”没有反映它。如何找到由进程分配的确切内存？ [英] "Private Bytes" doesn't reflect it. How to find exact memory allocated by process?

问题描述

这里是使用VS2010在Windows XP上编译和运行的C ++代码示例。

Here is sample piece of C++ code compiled and run using VS2010 on Windows XP.

在分配前后打印私有字节。

It prints "private bytes" before and after allocation.

void PrintPrivateBytes()
{
    HANDLE current_process;
    PROCESS_MEMORY_COUNTERS_EX pmc;

    current_process = GetCurrentProcess();

    if (!GetProcessMemoryInfo(current_process, (PPROCESS_MEMORY_COUNTERS)&pmc, sizeof(pmc)))
    {
        std::cout << "\nGetProcessMemoryInfo failed" ;
        return;
    }

    std::cout << "\nProcess private bytes: " << pmc.PrivateUsage/1024 << " KB"; 
}

int _tmain(int argc, _TCHAR* argv[])
{
    // Code demonstrating private bytes doesn't change
    std::cout << "\n\nBefore allocating memory" ;
    PrintPrivateBytes();

    char* charptr = new char[8192];
    std::cout << "\n\nAfter allocating 8 KB memory" ;
    PrintPrivateBytes();

    delete[] charptr;
    std::cout << "\n\nAfter deleting memory" ;
    PrintPrivateBytes();

    int RetVal = _heapmin();
    std::cout << "\n\nAfter calling _heapmin" ;
    PrintPrivateBytes();

    return 0;
}

这里是输出：

分配内存之前

Before allocating memory

处理私人字节：416 KB

Process private bytes: 416 KB

分配内存

处理专用字节：428 KB

Process private bytes: 428 KB

删除内存后

处理私人字节：428 KB

Process private bytes: 428 KB

调用_heapmin后

After calling _heapmin

处理私人字节：428 KB

Process private bytes: 428 KB

它指示私有字节不反映进程的确切内存使用情况。

It indicates "private bytes" doesn't reflect exact memory usage of process.

哪些Windows API /结构有助于查找进程的确切内存使用情况？
（工作集也没有用，它只反映了物理内存的使用方式）

Which Windows API/structure will help finding exact memory usage of process ? (Working set is also of no use. It just reflect much how physical memory is being used)

推荐答案

检查私有字节的解决方案是正确的，只有你对_heapmin的假设是错误的。

Your solution of checking the private bytes is correct, only your assumption about _heapmin is wrong.

_heapmin不能正常工作。 _heapmin是记录为向操作系统释放未使用的堆内存。

_heapmin does not work as documented. _heapmin is documented as "Releases unused heap memory to the operating system."

实施（请参阅\Program文件（x86）\ Microsoft Visual Studio 10.0 \VC\crt\src\heapmin.c）

The implementation (see "\Program Files (x86)\Microsoft Visual Studio 10.0\VC\crt\src\heapmin.c") is

int __cdecl _heapmin(void)
{
        if ( HeapCompact( _crtheap, 0 ) == 0 ) {
            return -1;
        }
        else {
            return 0;
        }
}

HeapCompact 记录通常做什么，尽管返回的大小堆中最大的空闲块。如果使用特殊的全局（调试目的）标志，它只会做一些额外的东西。

HeapCompact is documented to normally do quite nothing despite returning the size of the largest free block in the heap. It only does some extra stuff if a special global (debug purpose) flag is used.

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