On Thu, Oct 22, 2015 at 13:52:29 +0100, Daniel P. Berrange wrote:
...
> On a related topic, we don't have great error reporting in the (usually
> unlikely) scenario that we get a stuck job / timeout. I've long thought
> it could be desirable to record some metadata when we start jobs, such
> as the __FUNC__ of the method which started the job, so when we report
> an error we can include that info as a diagnostic aid.
Do you mean something like
virsh # resume cd
error: Failed to resume domain cd
error: Timed out during operation: cannot acquire state change lock
(held by remoteDispatchDomainSuspend)
This was implemented by v1.2.13-295-gb79f25e
> This would
> have to be against the qemuDomainObjPrivPtr struct. THis makes me
> think that using the separate bool inJob/inMonitor stack variables
> is not required.
>
> We could just add
>
> int threadid;
> bool inJob;
> bool inMonitor;
> const char *jobfunc;
>
> to qemuDomainObjPrivPtr. That way you don't need to modify the
> Enter/Exit functions to add extra arguments - we just track
> everything internally. When exiting, we'd compare against the
> threadid, to make sure we don't accidentally relaase a different
> thread's job.
Yeah, as long as we can make sure threadid is unique and stable:
/* These next two functions are for debugging only, since they are not
* guaranteed to give unique values for distinct threads on all
* architectures, nor are the two functions guaranteed to give the same
* value for the same thread. */
unsigned long long virThreadSelfID(void);
unsigned long long virThreadID(virThreadPtr thread);
so far we avoided using thread IDs for anything critical.
Jirka
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