Hi!
On 14:03 Wed 14 Jul , Kulikov Vasiliy wrote:
> Hi folks,
>
> I wonder whether any kernel code is swapped out in some cases? E.g. in
> windows NT kernel kernel code is divided into two parts - swappable and
> nonswappable, there is specific macros to mark the code being swappable.
>
> So, as I understand, all kernel code (including modules) and all
> static/global data is unswappable, all dynamic memory allocated with
> GFP_ATOMIC is unswappable, with GFP_KERNEL is swappable. Am I right?
No, GFP_KERNEL is not swappable and I am not aware of any kernel memory which
is. This flag determines the behaviour when allocating memory:
GFP_ATOMIC fail immediately, if no memory is available; This is needed is some
cases where the code cannot sleep (e.g. interrupt context)
GFP_KERNEL put the code to sleep and try to free memory e.g. by swapping user
space memory to disk; However, this does not mean that allocations are always
successful either.
-Michi
--
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com
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