[libvirt] [PATCH 0/5] Introduce VIR_CONNECT_GET_ALL_DOMAINS_STATS_BEST_EFFORT

[Michal Privoznik]

On 06/07/2018 02:53 PM, Daniel P. Berrangé wrote:
> On Thu, Jun 07, 2018 at 01:59:11PM +0200, Michal Privoznik wrote:
>> Problem is, if there is a long standing job on a domain fetching
>> statistics might hiccup which might be a problem for mgmt apps that
>> query stats every few seconds.
>>
>> Orthogonal to this, I think we should break our sync QEMU_JOB_* into two
>> separate jobs: one for qemu monitor the other for qemu guest agent.
>> Problem is, if thread A grabs QEMU_JOB_MODIFY and talks only to guest
>> agent it prevents thread B from grabbing QEMU_JOB_QUERY which wants to
>> talk only to qemu monitor. But this is a different can of worms and I
>> haven't thought it through completely just yet.
> 
> Yeah, I think that is important todo because the guest agent is untrusted
> service and so can arbitrarily delay its response to libvirt. Even though
> we timeout the agent after a while, we shouldn't really let it delay other
> APIs using the monitor.

Indeed. I'm working on it as we speak. Nevertheless, these patches are
independent of that (in case any reviewer is waiting for those patches
first).

Michal