Memory question

[foudfou]

Hi there, thank you so much as I'm learning a lot from your project! I am currently tackling paging.

I have a question about this line

hux-kernel/src/memory/paging.c

Line 52 in 7fea5c5

if (kheap_curr + size > KMEM_MAX)

Something I'm not sure to understand is: while kheap_curr is initialized to a page-aligned memory address right after the kernel, which itself is loaded to 1MiB, we compare kheap_curr to something that looks like a quantity:

#define KMEM_MAX 0x00800000     /** 8MiB reserved for the kernel. */

In practice, KMEM_MAX is used as an address, and the comment should read something like: /* Max address reserved for the kernel */.

What am I missing?

[josehu07]

Hi there, thanks for asking.

Yes, your understanding is correct. 8MiB is the max address reserved for kernel stuff. The comment should read up to 8MiB reserved for the kernel.

The amount of available memory for kernel heap and slabs will be less than 8MiB.