[libvirt] [libvirt-python PATCH 2/2] Support virDomainSetIOThreads

[Pavel Hrdina]

On Thu, Feb 19, 2015 at 07:59:39AM -0500, John Ferlan wrote:
> Support the libvirt_virDomainSetIOThreads method using code that mimics
> the existing libvirt_virDomainPinVcpuFlags method
> 
> The following is a sample session assuming guest 'iothr-gst' has IOThreads
> configured (it's currently running, too)
> 
> >>> import libvirt
> >>> con=libvirt.open("qemu:///system")
> >>> dom=con.lookupByName('iothr-gst')
> >>> dom.getIOThreadsInfo()
> [(1, [False, False, True, False], ['/home/vm-images/iothr-vol1']), (2, [False, False, False, True], ['/home/vm-images/iothr-vol2']), (3, [False, False, False, True], [])]
> >>> cpumap=(True,True,True,False)
> >>> dom.setIOThreads(3,cpumap)
> 0
> >>> print dom.getIOThreadsInfo()
> [(1, [False, False, True, False], ['/home/vm-images/iothr-vol1']), (2, [False, False, False, True], ['/home/vm-images/iothr-vol2']), (3, [True, True, True, False], [])]
> >>>
> 
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
>  generator.py             |  1 +
>  libvirt-override-api.xml |  8 ++++++
>  libvirt-override.c       | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 76 insertions(+)
> 
> diff --git a/generator.py b/generator.py
> index 327c896..c79acf1 100755
> --- a/generator.py
> +++ b/generator.py
> @@ -436,6 +436,7 @@ skip_impl = (
>      'virDomainGetEmulatorPinInfo',
>      'virDomainPinEmulator',
>      'virDomainGetIOThreadsInfo',
> +    'virDomainSetIOThreads',
>      'virSecretGetValue',
>      'virSecretSetValue',
>      'virSecretGetUUID',
> diff --git a/libvirt-override-api.xml b/libvirt-override-api.xml
> index e512311..19667b6 100644
> --- a/libvirt-override-api.xml
> +++ b/libvirt-override-api.xml
> @@ -284,6 +284,14 @@
>        <arg name='flags'  type='int' info='an OR'ed set of virDomainModificationImpact'/>
>        <return type='char *' info="list of IOThreads information including the iothread_id, the cpumap, the cpumap length, number of associated resources, and a list of each resource assigned to the iothread_id."/>
>      </function>
> +    <function name='virDomainSetIOThreads' file='python'>
> +      <info>Dynamically change the real CPUs which can be allocated to an IOThread. This function requires privileged access to the hypervisor.</info>
> +      <return type='int' info='0 in case of success, -1 in case of failure.'/>
> +      <arg name='domain' type='virDomainPtr' info='pointer to domain object'/>
> +      <arg name='iothread_val' type='unsigned int' info='iothread_id number'/>
> +      <arg name='cpumap' type='unsigned char *' info='pointer to a bit map of real CPUs (in 8-bit bytes) (IN) Each bit set to 1 means that corresponding CPU is usable. Bytes are stored in little-endian order: CPU0-7, 8-15... In each byte, lowest CPU number is least significant bit.'/>
> +      <arg name='flags'  type='int' info='an OR'ed set of virDomainIOThreadsFlags'/>
> +    </function>
>      <function name='virDomainSetSchedulerParameters' file='python'>
>        <info>Change the scheduler parameters</info>
>        <return type='int' info='-1 in case of error, 0 in case of success.'/>
> diff --git a/libvirt-override.c b/libvirt-override.c
> index 17f3bf3..f9af5a9 100644
> --- a/libvirt-override.c
> +++ b/libvirt-override.c
> @@ -2082,6 +2082,72 @@ cleanup:
>      return VIR_PY_NONE;
>  }
>  
> +static PyObject *
> +libvirt_virDomainSetIOThreads(PyObject *self ATTRIBUTE_UNUSED,
> +                              PyObject *args)
> +{
> +    virDomainPtr domain;
> +    PyObject *pyobj_domain, *pycpumap;
> +    PyObject *ret = NULL;
> +    unsigned char *cpumap;
> +    int cpumaplen, iothread_val, tuple_size, cpunum;
> +    size_t i;
> +    unsigned int flags;
> +    int i_retval;
> +
> +    if (!PyArg_ParseTuple(args, (char *)"OiOI:virDomainSetIOThread",
> +                          &pyobj_domain, &iothread_val, &pycpumap, &flags))
> +        return NULL;
> +    domain = (virDomainPtr) PyvirDomain_Get(pyobj_domain);
> +
> +    if ((cpunum = getPyNodeCPUCount(virDomainGetConnect(domain))) < 0)
> +        return VIR_PY_INT_FAIL;
> +
> +    if (PyTuple_Check(pycpumap)) {
> +        tuple_size = PyTuple_Size(pycpumap);
> +        if (tuple_size == -1)

This could be merged into one line as the condition before. And returning NULL
is correct because the PyTuple_Size sets an exception in case of failure.

> +            return ret;
> +    } else {
> +       PyErr_SetString(PyExc_TypeError, "Unexpected type, tuple is required");
> +       return ret;
> +    }
> +
> +    cpumaplen = VIR_CPU_MAPLEN(cpunum);
> +    if (VIR_ALLOC_N(cpumap, cpumaplen) < 0)
> +        return PyErr_NoMemory();
> +
> +    for (i = 0; i < tuple_size; i++) {
> +        PyObject *flag = PyTuple_GetItem(pycpumap, i);
> +        bool b;
> +
> +        if (!flag || libvirt_boolUnwrap(flag, &b) < 0)
> +            goto cleanup;
> +
> +        if (b)
> +            VIR_USE_CPU(cpumap, i);
> +        else
> +            VIR_UNUSE_CPU(cpumap, i);
> +    }
> +
> +    for (; i < cpunum; i++)
> +        VIR_UNUSE_CPU(cpumap, i);
> +
> +    flags |= VIR_DOMAIN_IOTHREADS_PIN;
> +    LIBVIRT_BEGIN_ALLOW_THREADS;
> +    i_retval = virDomainSetIOThreads(domain, iothread_val,
> +                                     cpumap, cpumaplen, flags);
> +    LIBVIRT_END_ALLOW_THREADS;
> +    if (i_retval < 0) {
> +        ret = VIR_PY_INT_FAIL;
> +        goto cleanup;
> +    }
> +    ret = VIR_PY_INT_SUCCESS;
> +
> +cleanup:
> +    VIR_FREE(cpumap);
> +    return ret;
> +}
> +
>  #endif /* LIBVIR_CHECK_VERSION(1, 2, 13) */
>  
>  /************************************************************************
> @@ -8578,6 +8644,7 @@ static PyMethodDef libvirtMethods[] = {
>  #endif /* LIBVIR_CHECK_VERSION(0, 10, 0) */
>  #if LIBVIR_CHECK_VERSION(1, 2, 13)
>      {(char *) "virDomainGetIOThreadsInfo", libvirt_virDomainGetIOThreadsInfo, METH_VARARGS, NULL},
> +    {(char *) "virDomainSetIOThreads", libvirt_virDomainSetIOThreads, METH_VARARGS, NULL},
>  #endif /* LIBVIR_CHECK_VERSION(1, 2, 13) */
>      {(char *) "virConnectListStoragePools", libvirt_virConnectListStoragePools, METH_VARARGS, NULL},
>      {(char *) "virConnectListDefinedStoragePools", libvirt_virConnectListDefinedStoragePools, METH_VARARGS, NULL},
> -- 
> 2.1.0

ACK with the change proposed above.

Pavel

> 
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