Re: Kernel vs user memory

Bryan Donlan
2009-01-17T04:16:29Z

On Fri, Jan 16, 2009 at 9:56 PM, sidc7 <siddhartha.chhabra@gmail.com> wrote:
>
> The kernel maintains a free list of pages that are free in physical memory. I
> was wondering, are these pages in the kernel space ? They are not mapped to
> any of the user address space for sure, so will they be in the kernel memory
> ?

Of course. Note that much of user address space is also mapped into
kernel address space (all of it, in fact, unless you're on a 32-bit
x86 system with PAE and more than 3G or so of RAM), so such a clear
division isn't quite that easy :)

All the gory details are in mm/page_alloc.c and mm/slab.c (or slub.c
or slob.c, depending on your build configuration).