Hi,

Linux kernel basically manages all available physical memory pages.
If user-space need a page, kernel allocates a page for it. Hence a
physical page may be in mapped to user-space virtual address or 
kernel-space virtual address or both.

The user-space and kernel-space exist in virtual address space, not
physical.

Thanks,
Min-Hua

On Wed, May 27, 2015 at 09:12:11AM +0800, Le Tan wrote:

Hi,
Is there an explict split between userspace and kernel in physical
memory on Linux x86-64? That is, given a physical address, can I tell
whether this address is from userspace or not?
As far as I know, in virtual address space, the kernel will use the
upper half and the userspace will use the lower half. But what about
in physical address space?

Thanks very much!

Le

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies