Page fault in kernel code

[Valdis.Kletnieks at vt.edu]

On Wed, 10 Sep 2014 14:45:23 +0530, Manavendra Nath Manav said:

> But if the total RAM is limited (less than 896MB LOWMEM), for example as in
> embedded devices how the kernel code be kept in RAM all the time. Am I
> correct to assume that the kernel pre-fetches all pages when entering
> kernel mode from user mode?

No, kernel code is loaded by your boot loader, and *it stays there*.  Similarly,
if you modprobe something, the kernel allocates the page, loads the code,
and leaves it there.

Particularly in embedded devices, where you know all the modules the kernel may
need, it's common to just create a kernel with everything built in, no module
support, and when the system boots, it loads into memory and never moves again.

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