is linux still a none swappable kernel?

is linux still a none swappable kernel?

[Rodrigo Amestica]

In some older posts I have read that memory allocations via kmalloc
and vmalloc are not swappable, that is, these memory chunks are not
paged out to swap area. Is this still the case with linux kernel 2.6?

thanks,

Re: is linux still a none swappable kernel?

[Heiko Carstens]

On Sun, May 13, 2007 at 01:12:12PM -0400, Rodrigo Amestica wrote:
> In some older posts I have read that memory allocations via kmalloc
> and vmalloc are not swappable, that is, these memory chunks are not
> paged out to swap area. Is this still the case with linux kernel 2.6?

Yes.

Re: is linux still a none swappable kernel?

[Rik van Riel]

Rodrigo Amestica wrote:
> In some older posts I have read that memory allocations via kmalloc
> and vmalloc are not swappable, that is, these memory chunks are not
> paged out to swap area. Is this still the case with linux kernel 2.6?

Yes.

Unswappable kernel memory is simpler and faster.

Over the last 15 years, the memory requirements of the
Linux kernel have grown maybe a factor 10, while the
memory of computers has grown by a factor of 1000.

The data structures that grow with memory (mostly the
mem_map[] array of page structs) has actually gotten
smaller since the 2.4 kernel and now takes under 1%
of memory even on x86-64.

There really is no good reason for swapping kernel
memory nowadays.

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