xenstore memory issue

[Andrew Thompson]

On 14 February 2015 at 05:31, Roger Pau Monné <roger.pau at citrix.com> wrote:

> El 13/02/15 a les 0.46, Andrew Thompson ha escrit:
> > On 11 February 2015 at 05:22, Roger Pau Monné <roger.pau at citrix.com>
> wrote:
> >
> >> Hello Andrew,
> >>
> >> El 10/02/15 a les 10.22, Andrew Thompson ha escrit:
> >>> On 10 February 2015 at 16:25, Andrew Thompson <thompsa at freebsd.org>
> >> wrote:
> >>>
> >>>> On 9 February 2015 at 23:28, Roger Pau Monné <roger.pau at citrix.com>
> >> wrote:
> >>>> A bit of trial and error with dtrace has narrowed this down. I can
> cause
> >>>> the leak by just opening /dev/xen/xenstore
> >>
> >> Thanks for doing all this legwork! IMHO the best solution is to switch
> >> xenstore dev to use cdevpriv in order to store each client data. What we
> >> are doing right now (storing client data in dev->si_dvr1) is plain
> >> wrong. I've uploaded two patches (one for HEAD and one for stable/10) so
> >> that you can try it also, please report back whether this fixes your
> >> problem or not:
> >>
> >> https://people.freebsd.org/~royger/xenstore_fix/
> >>
> >>
> > I have tested this on 10.0 and it does fix the issue. After 36000
> > allocations there are just 6 active at 13K
> >
> > xenstore     6    13K       -    36699  16,32,64,128,256,512
> >
> >
> > I looked in to why this only affected one of my many VMs as they run
> > xe-update-guest-attrs and nova-agent which should have triggered the
> leak.
> > They are all stuck on xsdread when reading from the xenstore so the
> update
> > loop has stopped.
> >
> >   UID   PID  PPID CPU PRI NI    VSZ   RSS MWCHAN   STAT TT          TIME
> > COMMAND
> >     0 13250 13249   0  20  0  16552  1968 xsdread  S     -       5:57.60
> > /usr/local/bin/xenstore-read domid (xenstore)
>
> Is this with my patch applied? AFAICT xsdread means it's waiting on the
> address at dev->si_drv1, which is completely wrong because every time
> the device was opened this address changed. With my patch applied it
> should no longer be an issue.
>
>
No, I was looking at the other unpatched servers, I didnt realise the two
issues were linked. Please commit!


cheers,
Andrew