Re: KSM with Debian GNU/Linux

[Michael Tokarev <mjt@tls.msk.ru>]

09.08.2010 15:00, Nikola Ciprich пишет:
> Hi,
> I don't have clue what glibc is contained in debian, but it seems
> to me that at least compile-time KSM support DOES depend on glibc.
> I'm using RHEL5-based system and KSM support doesn't get compiled in
> by default.

For KSM to be compiled in, one need to have kernel headers of the
corresponding system interface (madvise() system call).  That is
not part of glibc (even while madvise function is declared by glibc)
but part of kernel headers which glibc uses itself during compilation.

In debian that comes in linux-libc-dev package, some other distribution
may bundle it together with glibc but that's pure packaging stuff,
these headers does not come from glibc sources.

> But since I use new kernel, I add following to CFLAGS while compiling
> qemu-kvm and then it works:
> -DMADV_MERGEABLE=12 -DMADV_UNMERGEABLE=13

This is what the patch in debian package does, to get KSM-ready binary
even without recent-enough kernel headers (like on Lenny).

/mjt