[libvirt] [PATCH v3 3/9] qemu: Implement the qemu driver fetch for IOThreads

[Ján Tomko]

On Tue, Feb 17, 2015 at 04:03:52PM -0500, John Ferlan wrote:
> Depending on the flags passed, either attempt to return the active/live
> IOThread data for the domain or the config data.
> 
> The active/live path will call into the Monitor in order to get the
> IOThread data and then correlate the thread_id's returned from the
> monitor to the currently running system/threads in order to ascertain
> the affinity for each iothread_id.
> 
> The config path will map each of the configured IOThreads and return
> any configured iothreadspin data
> 
> Both paths will peruse the 'targetDef' domain list looking for 'disks'
> that have been assigned to a specific IOThread.  An IOThread may have
> no resources associated
> 
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
>  src/qemu/qemu_driver.c | 281 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 281 insertions(+)
> 

Just a few nits, until the API gets final...

> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 1bbbe9b..2c9d08c 100644

> +static int
> +
> +    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0)
> +        goto cleanup;
> +
> +    if (!virDomainObjIsActive(vm)) {
> +        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
> +                       _("cannot list IOThreads for an inactive domain"));
> +        goto endjob;
> +    }
> +
> +    priv = vm->privateData;
> +    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_OBJECT_IOTHREAD)) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                       _("IOThreads not supported with this binary"));
> +        goto endjob;
> +    }
> +
> +    if (qemuDomainObjEnterMonitorAsync(driver, vm, QEMU_ASYNC_JOB_NONE) < 0)
> +        goto endjob;

EnterMonitorAsync with ASYNC_JOB_NONE is essentially EnterMonitor

> +    for (i = 0; i < targetDef->iothreads; i++) {
> +        if (VIR_ALLOC(info_ret[i]) < 0)
> +            goto cleanup;
> +
> +        /* IOThreads being counting at 1 */
> +        info_ret[i]->iothread_id = i + 1;
> +
> +        if (VIR_ALLOC_N(info_ret[i]->cpumap, maplen) < 0)
> +            goto cleanup;
> +
> +        /* Initialize the cpumap */
> +        info_ret[i]->cpumaplen = maplen;
> +        memset(info_ret[i]->cpumap, 0xff, maplen);
> +        if (maxcpu % 8)
> +            info_ret[i]->cpumap[maplen - 1] &= (1 << maxcpu % 8) - 1;

virBitmapToData could make this more readable.

> +    }
> +
> +    /* If iothreadspin setting exists, there are unused physical cpus */
> +    iothreadspin_list = targetDef->cputune.iothreadspin;

A temporary variable pointing to iothreadspin[i] is more common.

> +    for (i = 0; i < targetDef->cputune.niothreadspin; i++) {
> +        /* vcpuid is the iothread_id...
> +         * iothread_id is the index into info_ret + 1, so we can
> +         * assume that the info_ret index we want is vcpuid - 1
> +         */
> +        cpumap = info_ret[iothreadspin_list[i]->vcpuid - 1]->cpumap;
> +        cpumask = iothreadspin_list[i]->cpumask;
> +
> +        for (pcpu = 0; pcpu < maxcpu; pcpu++) {
> +            if (virBitmapGetBit(cpumask, pcpu, &pinned) < 0)
> +                goto cleanup;
> +            if (!pinned)
> +                VIR_UNUSE_CPU(cpumap, pcpu);
> +        }
> +    }
> +

Jan
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