[libvirt] [RFC PATCH 2/2] Routines to parse <numa> ... </numa>

[Bharata B Rao]

On Thu, Oct 13, 2011 at 12:50:00PM +0100, Daniel P. Berrange wrote:
> On Mon, Oct 03, 2011 at 03:31:35PM +0530, Bharata B Rao wrote:
> > Routines to parse <numa> ... </numa>
> > 
> > From: Bharata B Rao <bharata at linux.vnet.ibm.com>
> > 
> > This patch adds routines to parse guest numa
> > XML configuration for qemu.
> > 
> > Signed-off-by: Bharata B Rao <bharata at linux.vnet.ibm.com>
> > ---
> > 
> >  src/conf/cpu_conf.c     |   48 ++++++++++++++++++++++++
> >  src/conf/cpu_conf.h     |   11 ++++++
> >  src/qemu/qemu_command.c |   94 +++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 153 insertions(+), 0 deletions(-)
> > 
> > 
> > diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> > index a13ba71..5b4345e 100644
> > --- a/src/qemu/qemu_command.c
> > +++ b/src/qemu/qemu_command.c
> > @@ -3153,6 +3153,97 @@ qemuBuildSmpArgStr(const virDomainDefPtr def,
> >      return virBufferContentAndReset(&buf);
> >  }
> >  
> > +static char *
> > +virParseNodeCPUs(char *cpumask)
> 
> This is a rather misleading name, since it is really formatting
> the argument value. Can you rename this to qemuBuildNumaCPUArgStr

Sure will do.

> 
> > +{
> > +    int i, first, last, ret;
> > +    char *cpus, *ptr;
> > +    int cpuSet = 0;
> > +    int remaining = 128;
> > +
> > +    if (VIR_ALLOC_N(cpus, remaining) < 0)
> > +        return NULL;
> > +
> > +    ptr = cpus;
> > +
> > +    for (i = 0; i < VIR_DOMAIN_CPUMASK_LEN; i++) {
> > +        if (cpumask[i]) {
> > +            if (cpuSet)
> > +                last = i;
> > +            else {
> > +                first = last = i;
> > +                cpuSet = 1;
> > +            }
> > +        } else {
> > +            if (!cpuSet)
> > +                continue;
> > +            if (first == last)
> > +                ret = snprintf(ptr, remaining, "%d,", first);
> > +            else
> > +                ret = snprintf(ptr, remaining, "%d-%d,", first, last);
> > +            if (ret > remaining)
> > +                goto error;
> > +            ptr += ret;
> > +            remaining -= ret;
> > +            cpuSet = 0;
> > +	}
> > +    }
> > +
> > +    if (cpuSet) {
> > +        if (first == last)
> > +            ret = snprintf(ptr, remaining, "%d,", first);
> > +        else
> > +            ret = snprintf(ptr, remaining, "%d-%d,", first, last);
> > +        if (ret > remaining)
> > +            goto error;
> > +    }
> > +
> > +    /* Remove the trailing comma */
> > +    *(--ptr) = '\0';
> > +    return cpus;
> > +
> > +error:
> > +    VIR_FREE(cpus);
> > +    return NULL;
> 
> Using VIR_ALLOC_N + snprintf here is not desirable, when you
> already have a nice  virBufferPtr object in the call that you
> could use.  Just pass the virBufferPtr straight into this
> method.

Wanted to user virBufferPtr, but I realized that I need to remove
the last comma from the string and coudn't find an easy way to
do that. Hence resorted to this method. But I think I can still
achive this by not appending a comma to the next part of the agrument
(,mems). Let me see if I can do this cleanly in the next post.

> 
> > +}
> > +
> > +static int
> > +qemuBuildNumaArgStr(const virDomainDefPtr def, virCommandPtr cmd)
> > +{
> > +    int i;
> > +    char *cpus, *node;
> > +    virBuffer buf = VIR_BUFFER_INITIALIZER;
> > +
> > +    for (i = 0; i < def->cpu->nnodes; i++) {
> > +        virCommandAddArg(cmd, "-numa");
> > +        virBufferAsprintf(&buf, "%s", "node");
> > +        virBufferAsprintf(&buf, ",nodeid=%d", def->cpu->nodes[i].nodeid);
> > +
> > +        cpus = virParseNodeCPUs(def->cpu->nodes[i].cpumask);
> > +        if (!cpus)
> > +            goto error;
> > +
> > +        virBufferAsprintf(&buf, ",cpus=%s", cpus);
> > +        virBufferAsprintf(&buf, ",mems=%d", def->cpu->nodes[i].mem);
> > +
> > +        if (virBufferError(&buf)) {
> > +            VIR_FREE(cpus);
> > +            goto error;
> > +        }
> > +
> > +        node = virBufferContentAndReset(&buf);
> > +        virCommandAddArg(cmd, node);
> > +
> > +        VIR_FREE(cpus);
> > +        VIR_FREE(node);
> > +    }
> > +    return 0;
> > +
> > +error:
> > +    virBufferFreeAndReset(&buf);
> > +    virReportOOMError();
> > +    return -1;
> > +}
> >  
> >  /*
> >   * Constructs a argv suitable for launching qemu with config defined
> > @@ -3319,6 +3410,9 @@ qemuBuildCommandLine(virConnectPtr conn,
> >      virCommandAddArg(cmd, smp);
> >      VIR_FREE(smp);
> >  
> > +    if (def->cpu->nnodes && qemuBuildNumaArgStr(def, cmd))
> > +        goto error;
> > +
> >      if (qemuCapsGet(qemuCaps, QEMU_CAPS_NAME)) {
> >          virCommandAddArg(cmd, "-name");
> >          if (driver->setProcessName &&
> 
> Looks fine code wise. For the future iterations, it would be good to
> change the split of patches slightly
> 
>   - Patch 1 for XML bits:  cpu_conf.c, cpu_conf.h, and docs/schemas/domain.rn
>   - Patch 2 for qemu_command.c, tests/qemuxml2argvtest.c

Sure will rearrange in the next iteration.

Thanks for your review.

Regards,
Bharata.