problems getting KSM running on newer 2.6.32.x kernels

problems getting KSM running on newer 2.6.32.x kernels

[Nikola Ciprich]

Hello,
it seems to me that after upgrading to some 2.6.32.x release, KSM stopped working
for me. I'm not exactly sure which update did this, but enabling KSM doesn't
seem to do anything, ksmd process just sleeps and doesn't merge any memory.
Early 2.6.32 versions worked correctly for me, now I'm using 2.6.32.7 and qemu-kvm-0.12.2.

I'm enabling it using:

echo 262144 > /sys/kernel/mm/ksm/pages_to_scan
echo 100 > /sys/kernel/mm/ksm/sleep_millisecs
echo 1 > /sys/kernel/mm/ksm/run

Is there anything else I could check?
Thanks a lot for any hints
with best regards
nik


-- 
-------------------------------------
Ing. Nikola CIPRICH
LinuxBox.cz, s.r.o.
28. rijna 168, 709 01 Ostrava

tel.:   +420 596 603 142
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Re: problems getting KSM running on newer 2.6.32.x kernels

[Avi Kivity]

On 02/01/2010 12:37 PM, Nikola Ciprich wrote:
> Hello,
> it seems to me that after upgrading to some 2.6.32.x release, KSM stopped working
> for me. I'm not exactly sure which update did this, but enabling KSM doesn't
> seem to do anything, ksmd process just sleeps and doesn't merge any memory.
> Early 2.6.32 versions worked correctly for me, now I'm using 2.6.32.7 and qemu-kvm-0.12.2.
>
> I'm enabling it using:
>
> echo 262144>  /sys/kernel/mm/ksm/pages_to_scan
> echo 100>  /sys/kernel/mm/ksm/sleep_millisecs
> echo 1>  /sys/kernel/mm/ksm/run
>
>    

Izik?

-- 
error compiling committee.c: too many arguments to function

Re: problems getting KSM running on newer 2.6.32.x kernels

[Izik Eidus]

On Tue, 09 Feb 2010 12:51:47 +0200
Avi Kivity <avi@redhat.com> wrote:

> On 02/01/2010 12:37 PM, Nikola Ciprich wrote:
> > Hello,
> > it seems to me that after upgrading to some 2.6.32.x release, KSM stopped working
> > for me. I'm not exactly sure which update did this, but enabling KSM doesn't
> > seem to do anything, ksmd process just sleeps and doesn't merge any memory.
> > Early 2.6.32 versions worked correctly for me, now I'm using 2.6.32.7 and qemu-kvm-0.12.2.
> >
> > I'm enabling it using:
> >
> > echo 262144>  /sys/kernel/mm/ksm/pages_to_scan
> > echo 100>  /sys/kernel/mm/ksm/sleep_millisecs
> > echo 1>  /sys/kernel/mm/ksm/run

Is it happen to you just in 2.6.32.x? what happen with 2.6.33.x?

I have tested it on 2.6.33.x and it seems to work...

> >
> >    
> 
> Izik?
> 

Re: problems getting KSM running on newer 2.6.32.x kernels

[Nikola Ciprich]

Hi Avi, Izik,

today I spent some time investigating the problem and I've found the culprit:
RHEL5 glibc doesn't define MADV_MERGEABLE, so qemu-kvm didn't compile with KSM
support.
After I added -DMADV_MERGEABLE=12 -DMADV_UNMERGEABLE=13 CFLAGS,
things started to work.
Strange it worked for me before -  I don't remember using that kind of
hack before, but nevermind, it works now!

thanks and sorry for my fault.

have a nice day

nik

On Tue, Feb 09, 2010 at 03:02:17PM +0200, Izik Eidus wrote:
> On Tue, 09 Feb 2010 12:51:47 +0200
> Avi Kivity <avi@redhat.com> wrote:
> 
> > On 02/01/2010 12:37 PM, Nikola Ciprich wrote:
> > > Hello,
> > > it seems to me that after upgrading to some 2.6.32.x release, KSM stopped working
> > > for me. I'm not exactly sure which update did this, but enabling KSM doesn't
> > > seem to do anything, ksmd process just sleeps and doesn't merge any memory.
> > > Early 2.6.32 versions worked correctly for me, now I'm using 2.6.32.7 and qemu-kvm-0.12.2.
> > >
> > > I'm enabling it using:
> > >
> > > echo 262144>  /sys/kernel/mm/ksm/pages_to_scan
> > > echo 100>  /sys/kernel/mm/ksm/sleep_millisecs
> > > echo 1>  /sys/kernel/mm/ksm/run
> 
> Is it happen to you just in 2.6.32.x? what happen with 2.6.33.x?
> 
> I have tested it on 2.6.33.x and it seems to work...
> 
> > >
> > >    
> > 
> > Izik?
> > 
> 
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-- 
-------------------------------------
Ing. Nikola CIPRICH
LinuxBox.cz, s.r.o.
28. rijna 168, 709 01 Ostrava

tel.:   +420 596 603 142
fax:    +420 596 621 273
mobil:  +420 777 093 799
www.linuxbox.cz

mobil servis: +420 737 238 656
email servis: servis@linuxbox.cz
-------------------------------------