[libvirt] [REBASE PATCH v2 8/9] qemu: Allow showing the dump progress for memory only dump

[Jiri Denemark]

On Fri, Jan 19, 2018 at 14:53:15 -0500, John Ferlan wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=916061
> 
> If the QEMU version running is new enough (based on the DUMP_COMPLETED
> event), then we can add a 'detach' boolean to the dump-guest-memory
> command in order to tell QEMU to run in a thread. This ensures that we
> don't lock out other commands while the potentially long running dump
> memory is completed.
> 
> This allows the usage of a qemuDumpWaitForCompletion which will wait
> for the event while the qemuDomainGetJobInfoDumpStats can be used via
> qemuDomainGetJobInfo in order to query QEMU in order to determine
> how far along the job is.
> 
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
>  src/qemu/qemu_driver.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 44 insertions(+), 4 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index adf66228b..efb3652df 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -3758,6 +3758,34 @@ qemuDomainManagedSaveRemove(virDomainPtr dom, unsigned int flags)
>  }
>  
>  
> +/**
> + * qemuDumpWaitForCompletion:
> + * @vm: domain object
> + *
> + * If the query dump capability exists, then it's possible to start a
> + * guest memory dump operation using a thread via a 'detach' qualifier
> + * to the dump guest memory command. This allows the async check if the
> + * dump is done.
> + *
> + * Returns 0 on success, -1 on failure
> + */
> +static int
> +qemuDumpWaitForCompletion(virDomainObjPtr vm)
> +{
> +    qemuDomainObjPrivatePtr priv = vm->privateData;
> +
> +    if (!priv->job.dumpCompletion)
> +        return 0;

This condition can never be true in your code. You can just drop it
while dropping dumpCompletion.

> +
> +    VIR_DEBUG("Waiting for dump completion");
> +    while (!priv->job.dumpCompleted && !priv->job.abortJob) {
> +        if (virDomainObjWait(vm) < 0)
> +            return -1;
> +    }
> +    return 0;
> +}
> +
> +
>  static int
>  qemuDumpToFd(virQEMUDriverPtr driver,
>               virDomainObjPtr vm,
> @@ -3766,6 +3794,7 @@ qemuDumpToFd(virQEMUDriverPtr driver,
>               const char *dumpformat)
>  {
>      qemuDomainObjPrivatePtr priv = vm->privateData;
> +    bool detach = false;
>      int ret = -1;
>  
>      if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DUMP_GUEST_MEMORY)) {
> @@ -3774,10 +3803,13 @@ qemuDumpToFd(virQEMUDriverPtr driver,
>          return -1;
>      }
>  
> +    detach = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DUMP_COMPLETED);
> +
>      if (qemuSecuritySetImageFDLabel(driver->securityManager, vm->def, fd) < 0)
>          return -1;
>  
> -    VIR_FREE(priv->job.current);
> +    if (!detach)
> +        VIR_FREE(priv->job.current);
>      priv->job.dump_memory_only = true;
>  
>      if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
> @@ -3792,15 +3824,23 @@ qemuDumpToFd(virQEMUDriverPtr driver,
>                               "for this QEMU binary"),
>                             dumpformat);
>              ret = -1;
> +            ignore_value(qemuDomainObjExitMonitor(driver, vm));
>              goto cleanup;
>          }
>      }
>  
> -    ret = qemuMonitorDumpToFd(priv->mon, fd, dumpformat, false);
> +    ret = qemuMonitorDumpToFd(priv->mon, fd, dumpformat, detach);
>  
> - cleanup:
> -    ignore_value(qemuDomainObjExitMonitor(driver, vm));
> +    if (detach && ret == 0)
> +        priv->job.dumpCompletion = true;
> +
> +    if ((qemuDomainObjExitMonitor(driver, vm) < 0) || ret < 0)
> +        goto cleanup;
> +
> +    if (detach)
> +        ret = qemuDumpWaitForCompletion(vm);

We should update job.completed at this point.

>  
> + cleanup:
>      return ret;
>  }

Jirka