Basic HighMeM Question

[mulyadi.santosa@gmail.com (Mulyadi Santosa)]

Hi :)

On Wed, Jun 29, 2011 at 14:34, Paraneetharan Chandrasekaran
<paraneetharanc@gmail.com> wrote:
> Thanks Mulyadi for your clarifications!
> I am not getting the idea of "borrowing" last run process's address space. A
> kernel thread refers only the addresses in kernel's address space (low-mem
> area) which is mapped already, isnt it? How does the address space of last
> run task comes into picture?

Think like this: kernel thread is supposed to be operate entirely in
kernel space, right?

Then, you also agree that kernel address space is the same for all
running processess, correct? The only thing differs is their user
space mapping, right?

Based on this facts, kernel threads could simply use any last
scheduled process address space descriptor. Remember: its descriptor
(thus logically use its mapping too). Is it fine? sure... check the
above facts if you are confused. By using this trick, we save few
kilobytes by not allocating memory for yet another virtual memory
space descriptor (mm_struct and its VMAs)

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com