linux - 'low memory'在linux中是什么意思

Question

嗨，我是韩国人，对“ Bootstrap 首先将自身复制到固定的高端内存地址以为操作系统释放低端内存”感到困惑。

我通过谷歌搜索发现的关于低内存的知识是，这是 DOS 系统中的第一个 640K 内存。这是否意味着所有 OS 系统(如内核)都进入低内存(640K)？？？？

感谢阅读本文。

Answer 1

此链接可能会有帮助:Virtual Memory

主要是，

On 32-bit systems, memory is now divided into "high" and "low" memory. Low memory continues to be mapped directly into the kernel's address space, and is thus always reachable via a kernel-space pointer. High memory, instead, has no direct kernel mapping. When the kernel needs to work with a page in high memory, it must explicitly set up a special page table to map it into the kernel's address space first. This operation can be expensive, and there are limits on the number of high-memory pages which can be mapped at any particular time.

unix.stackexchange 上的这个问题更深入一点:High and low memory