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

[Martin Kletzander]

On Thu, Jul 07, 2016 at 01:43:32PM +0100, Daniel P. Berrange wrote:
>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
>

OK, I posted the first three patches as a clean-up separately so at
least we shave off some duplicated code ;)

>
>Regards,
>Daniel
>--
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>
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