System processes recognition.

[David Xu]

Bruce Evans wrote:

>
> P_SYSTEM for init is bogus since it breaks at least procfs for init.
> procfs may need to be disabled for init for security reasons, but it
> shouldn't be disabled unconditionally.  I mainly noticed /proc/1/map
> not existing.
>
> There should be flags like P_KTHREAD as needed to make the properties
> of init independent.
>
> I use the following patches to mostly just remove the setting of P_SYSTEM
> for init.


Removing P_SYSTEM for init will cause it to be swapped out under heavy
memory pressure, we unlikely want to swap out init, otherwise it results 
zoombies
can not be recycled immediately, does anyone know that init is already be
locked into memory, e.g, by PHOLD ?

David Xu