c ++ new运营商可以在Windows上自动使用大页面吗？

Question

Let's say I've written a C++ program using Visual Studio and it uses the new operator to allocate memory. I'm wondering whether there is a way that makes new automatically use large pages instead of standard 4KB pages (ie, without explicit calls to VirtualAlloc by my program).

Thanks for your time.

Answer 1

You can override all new and delete operators. For example

void * operator new(size_t size)
{
    return malloc(size);
}

void operator delete(void * pointer)
{
    free(pointer);
}

As well you should override all variants of this operators:

• http://www.cplusplus.com/reference/new/operator%20new/
• http://www.cplusplus.com/reference/new/operator%20new%5B%5D/
• http://www.cplusplus.com/reference/new/operator%20delete/
• http://www.cplusplus.com/reference/new/operator%20delete%5B%5D/

Answer 2

Implementation specific, once again. All libraries are not restricted to doing that since all the standard says AFAIK is that new allocates memory for C++. For Microsoft's implementation, new always calls HeapAlloc.

http://cboard.cprogramming.com/cplusplus-programming/98364-new-invokes-virtualalloc.html

My understanding is that unless you're running in a virtual machine, the OS has full control over the default heap and stack memory allocation. The above link also brings up a good point in line with Raymond's response to your question: Are you sure you need to use large pages? You open yourself to a good deal of internal fragmentation by doing so.