[libvirt] [PATCH v4 1/4] qemu: vcpu: Aggregate code to set vCPU tuning

[Ján Tomko]

On Mon, Feb 08, 2016 at 12:26:30PM +0100, Peter Krempa wrote:
> Rather than iterating 3 times for various settings this function
> aggregates all the code into single place. One of the other advantages
> is that it can then be reused for properly setting vCPU info on hotplug.
> 
> With this approach autoCpuset is also used when setting the process
> affinity rather than just via cgroups.
> ---
>  src/qemu/qemu_cgroup.c  |  95 ----------------------
>  src/qemu/qemu_cgroup.h  |   1 -
>  src/qemu/qemu_process.c | 212 ++++++++++++++++++++++++++++++++----------------
>  src/qemu/qemu_process.h |   4 +
>  4 files changed, 148 insertions(+), 164 deletions(-)
> 
> diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
> index 3cfc9e3..f3a9b5c 100644
> --- a/src/qemu/qemu_cgroup.c
> +++ b/src/qemu/qemu_cgroup.c
> @@ -1018,101 +1018,6 @@ qemuSetupCgroupCpusetCpus(virCgroupPtr cgroup,
>      return ret;
>  }
> 
> -int
> -qemuSetupCgroupForVcpu(virDomainObjPtr vm)
> -{
> -    virCgroupPtr cgroup_vcpu = NULL;
> -    qemuDomainObjPrivatePtr priv = vm->privateData;
> -    virDomainDefPtr def = vm->def;
> -    size_t i;
> -    unsigned long long period = vm->def->cputune.period;
> -    long long quota = vm->def->cputune.quota;
> -    char *mem_mask = NULL;
> -    virDomainNumatuneMemMode mem_mode;
> -
> -    if ((period || quota) &&
> -        !virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPU)) {
> -        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> -                       _("cgroup cpu is required for scheduler tuning"));
> -        return -1;
> -    }
> -

Before, this error was reported...

> -    /*
> -     * If CPU cgroup controller is not initialized here, then we need
> -     * neither period nor quota settings.  And if CPUSET controller is
> -     * not initialized either, then there's nothing to do anyway. CPU pinning
> -     * will be set via virProcessSetAffinity.
> -     */
> -    if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPU) &&
> -        !virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPUSET))
> -        return 0;
> -
> -    /* If vCPU<->pid mapping is missing we can't do vCPU pinning */
> -    if (!qemuDomainHasVcpuPids(vm))
> -        return 0;

... before the VCPU pid check here.

> -
> -    if (virDomainNumatuneGetMode(vm->def->numa, -1, &mem_mode) == 0 &&
> -        mem_mode == VIR_DOMAIN_NUMATUNE_MEM_STRICT &&
> -        virDomainNumatuneMaybeFormatNodeset(vm->def->numa,
> -                                            priv->autoNodeset,
> -                                            &mem_mask, -1) < 0)

>  /**
> + * qemuProcessSetupVcpu:
> + * @vm: domain object
> + * @vcpuid: id of VCPU to set defaults
> + *
> + * This function sets resource properities (affinity, cgroups, scheduler) for a

*properties.
Also, cgroups, affinity, scheduler is the order.

> + * vCPU. This function expects that the vCPU is online and the vCPU pids were
> + * correctly detected at the point when it's called.
> + *
> + * Returns 0 on success, -1 on error.
> + */
> +int
> +qemuProcessSetupVcpu(virDomainObjPtr vm,
> +                     unsigned int vcpuid)
> +{
> +    pid_t vcpupid = qemuDomainGetVcpuPid(vm, vcpuid);
> +    virDomainVcpuInfoPtr vcpu = virDomainDefGetVcpu(vm->def, vcpuid);
> +    qemuDomainObjPrivatePtr priv = vm->privateData;
> +    char *mem_mask = NULL;
> +    virDomainNumatuneMemMode mem_mode;
> +    unsigned long long period = vm->def->cputune.period;
> +    long long quota = vm->def->cputune.quota;
> +    virCgroupPtr cgroup_vcpu = NULL;
> +    virBitmapPtr cpumask;
> +    int ret = -1;
> +
> +    if ((period || quota) &&
> +        !virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPU)) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                       _("cgroup cpu is required for scheduler tuning"));
> +        goto cleanup;
> +    }
> +

This error won't be displayed if the domain has no VCPU pids.

ACK if you move it to the caller.

Jan
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