Pkg xen devel - Nov 2014 - Bug#767295: Bug#767295: Bug#767295: xl: apparent memory leak

On Sat, 2014-11-08 at 08:32 -0500, Gedalya wrote:
> On 11/08/2014 05:41 AM, Ian Campbell wrote:
> > Please can you try running xl under valgrind, something similar to
what
> > I described earlier should work.
> I guess it didn't find much..
Indeed not :-/

I managed to get a test box up and running, so I backported a couple of
additional upstream patches to help valgrind analyse Xen toolstacks and
even with those I'm not seeing leaks.

However with pmap I am seeing an additional

+00007f37f516a000   23852   14464   14464 rw---   [ anon ]

with each reboot. The size seems  to be the same each time. I can't
quite figure out what this new mapping is. I'll keep digging.

[...]
> > Could you also post your guest cfg file please.
> 
Thanks, nothing unusual here but worth confirming.

Ian.

[0] b1dfc531d8ad and 171c6d7ac17e, FWIW

On 11/09/2014 07:02 AM, Ian Campbell wrote:
> On Sat, 2014-11-08 at 08:32 -0500, Gedalya wrote:
>> On 11/08/2014 05:41 AM, Ian Campbell wrote:
>>> Please can you try running xl under valgrind, something similar to
what
>>> I described earlier should work.
>> I guess it didn't find much..
> Indeed not :-/
>
> I managed to get a test box up and running, so I backported a couple of
> additional upstream patches to help valgrind analyse Xen toolstacks and
> even with those I'm not seeing leaks.
>
> However with pmap I am seeing an additional
>
> +00007f37f516a000   23852   14464   14464 rw---   [ anon ]
>
> with each reboot. The size seems  to be the same each time. I can't
> quite figure out what this new mapping is. I'll keep digging.
>
> [...]
Yea. That's precisely what I was seeing. And even the first one 
shouldn't be there. There is no such block on xl processes for squeeze 
or wheezy VMs.
That memory block is just a bit larger than the size of the initrd in 
the VM, could there be a connection?

>
>>> Could you also post your guest cfg file please.
> Thanks, nothing unusual here but worth confirming.
>
> Ian.
>
> [0] b1dfc531d8ad and 171c6d7ac17e, FWIW
>

On 11/09/2014 07:18 AM, Gedalya wrote:
> That memory block is just a bit larger than the size of the initrd in 
> the VM, could there be a connection? 
Nope. I changed the initrd to 2.6mb and that memory block is still 
exactly at 23852 / 14464  / 14464.
Actually the process size is around 12 mb when pygrub is counting down 
to boot, then jumps up to 14+ mb