我可以做一个写入时复制的memcpy在Linux呢？ [英] Can I do a copy-on-write memcpy in Linux?

问题描述

我有一些code，其中我经常复制一个大的内存块，往往只能做很小的改动后。

I have some code where I frequently copy a large block of memory, often after making only very small changes to it.

我已经实现跟踪变化的系统，但我想这可能是很好，如果可能的话，告诉操作系统做一个写入时复制的记忆，让它只处理制作副本的那些变化的部分。不过虽然Linux确实写入时复制，例如当fork（）的ING，我无法找到控制它，做它自己的方式。

I have implemented a system which tracks the changes, but I thought it might be nice, if possible to tell the OS to do a 'copy-on-write' of the memory, and let it deal with only making a copy of those parts which change. However while Linux does copy-on-write, for example when fork()ing, I can't find a way of controlling it and doing it myself.

推荐答案

您最好的机会可能是的mmap（）原始数据文件，然后的mmap（）相同的文件再次使用 MAP_PRIVATE 。

Your best chance is probably to mmap() the original data to file, and then mmap() the same file again using MAP_PRIVATE.

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