[libvirt] [PATCH v2 5/5] qemu: Check for thread <=> memory alignment

[Daniel P. Berrange]

On Thu, Jul 07, 2016 at 01:42:33PM +0100, Daniel P. Berrange wrote:
> On Thu, Jul 07, 2016 at 02:12:32PM +0200, Martin Kletzander wrote:
> > Some settings may be confusing and in case users use numad placement in
> > combination with static placement we could warn them as it might not be
> > wanted (but it's not forbidden).
> > 
> > Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1254402
> > 
> > Signed-off-by: Martin Kletzander <mkletzan at redhat.com>
> > ---
> >  src/qemu/qemu_process.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 74 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> > index 0aab01fd4d50..c012b6efcab6 100644
> > --- a/src/qemu/qemu_process.c
> > +++ b/src/qemu/qemu_process.c
> > @@ -2304,6 +2304,76 @@ qemuProcessSetLinkStates(virQEMUDriverPtr driver,
> >  }
> > 
> > 
> > +static int
> > +qemuProcessCheckCpusMemsAlignment(virQEMUDriverPtr driver,
> > +                                  virDomainObjPtr vm,
> > +                                  virBitmapPtr cpumask,
> > +                                  const char *mem_mask)
> > +{
> > +    int ret = -1;
> > +    int hostnodes = 0;
> > +    char *cpumask_str = NULL;
> > +    char *tmpmask_str = NULL;
> > +    char *mem_cpus_str = NULL;
> > +    virCapsPtr caps = NULL;
> > +    virBitmapPtr tmpmask = NULL;
> > +    virBitmapPtr mem_cpus = NULL;
> > +    virBitmapPtr mem_nodes = NULL;
> > +    virDomainNumatuneMemMode mem_mode;
> > +
> > +    if (virDomainNumatuneGetMode(vm->def->numa, -1, &mem_mode) != 0)
> > +        return 0;
> > +
> > +    if (mem_mode != VIR_DOMAIN_NUMATUNE_MEM_STRICT)
> > +        return 0;
> > +
> > +    if (!mem_mask || !cpumask)
> > +        return 0;
> > +
> > +    if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
> > +        goto cleanup;
> > +
> > +    if (!(tmpmask = virBitmapNewCopy(cpumask)))
> > +        goto cleanup;
> > +
> > +    if ((hostnodes = virNumaGetMaxNode()) < 0)
> > +        goto cleanup;
> > +
> > +    if (virBitmapParse(mem_mask, &mem_nodes, hostnodes) < 0)
> > +        goto cleanup;
> > +
> > +    if (!(mem_cpus = virCapabilitiesGetCpusForNodemask(caps, mem_nodes)))
> > +        goto cleanup;
> > +
> > +    virBitmapSubtract(tmpmask, mem_cpus);
> > +    if (!virBitmapIsAllClear(tmpmask)) {
> > +        if (!(cpumask_str = virBitmapFormat(cpumask)))
> > +            goto cleanup;
> > +
> > +        if (!(tmpmask_str = virBitmapFormat(tmpmask)))
> > +            goto cleanup;
> > +
> > +        if (!(mem_cpus_str = virBitmapFormat(mem_cpus)))
> > +            goto cleanup;
> > +
> > +        VIR_WARN("CPUs '%s' in cpumask '%s' might not have access to any NUMA "
> > +                 "node in memory's nodeset '%s' which consists of CPUs: '%s'.",
> > +                 tmpmask_str, cpumask_str, mem_mask, mem_cpus_str);
> 
> We've had a general principle that we don't use VIR_WARN for this kind of
> thing, because libvirtd logs are genrally invisible to the person who is
> making the mistake. Meanwhile if this is intentional, we're spamming the
> logs for a situation the user explicitly chose.
> 
> So NACK to the entire patch, as it doesn't do anything useful IMHO.

BTW, I'd suggest NOTABUG on this


Regards,
Daniel
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