[libvirt] PATCH: Make UML/LXC drivers robust with bad NUMA data

[Daniel P. Berrange]

On Thu, Aug 13, 2009 at 01:08:01PM +0200, Daniel Veillard wrote:
> On Thu, Aug 13, 2009 at 11:58:16AM +0100, Daniel P. Berrange wrote:
> > commit e2052c24f39c71b3b8e92a983287f72176d73c77
> > Author: Daniel P. Berrange <berrange at redhat.com>
> > Date:   Thu Aug 13 11:56:31 2009 +0100
> > 
> >     Make LXC / UML drivers robust against NUMA topology brokenness
> >     
> >     Some kernel versions expose broken NUMA topology for some machines.
> >     This causes the LXC/UML drivers to fail to start. QEMU driver was
> >     already fixed for this problem
> >     
> >     * src/lxc_conf.c: Log and ignore failure to populate NUMA info
> >     * src/uml_conf.c: Log and ignore failure to populate NUMA info
> > 
> 
> > +    /* Some machines have problematic NUMA toplogy causing
> > +     * unexpected failures. We don't want to break the QEMU
> > +     * driver in this scenario, so log errors & carry on
> > +     */
> > +    if (nodeCapsInitNUMA(caps) < 0) {
> > +        virCapabilitiesFreeNUMAInfo(caps);
> 
>    Hum, right now this doesn't reset caps.nnumaCell
> 
> > +        VIR_WARN0("Failed to query host NUMA topology, disabling NUMA capabilities");
> > +    }
> >  
> >      /* XXX shouldn't 'borrow' KVM's prefix */
> >      virCapabilitiesSetMacPrefix(caps, (unsigned char []){ 0x52, 0x54, 0x00 });
> > diff --git a/src/uml_conf.c b/src/uml_conf.c
> > index 48e05a8..4f756d4 100644
> > --- a/src/uml_conf.c
> > +++ b/src/uml_conf.c
> > @@ -45,6 +45,7 @@
> >  #include "nodeinfo.h"
> >  #include "verify.h"
> >  #include "bridge.h"
> > +#include "logging.h"
> >  
> >  #define VIR_FROM_THIS VIR_FROM_UML
> >  
> > @@ -63,8 +64,14 @@ virCapsPtr umlCapsInit(void) {
> >                                     0, 0)) == NULL)
> >          goto no_memory;
> >  
> > -    if (nodeCapsInitNUMA(caps) < 0)
> > -        goto no_memory;
> > +    /* Some machines have problematic NUMA toplogy causing
> > +     * unexpected failures. We don't want to break the QEMU
> > +     * driver in this scenario, so log errors & carry on
> > +     */
> > +    if (nodeCapsInitNUMA(caps) < 0) {
> > +        virCapabilitiesFreeNUMAInfo(caps);
> > +        VIR_WARN0("Failed to query host NUMA topology, disabling NUMA capabilities");
> > +    }
> >  
> >      if ((guest = virCapabilitiesAddGuest(caps,
> >                                           "uml",
> 
>   Patch looks fine but IMHO we should add
>     caps->host.nnumaCell = 0;
> in virCapabilitiesFreeNUMAInfo() to be 100% sure

Yes, I've pushed it with that addition.


Daniel
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