Re: [libvirt] [PATCH 1/8] qemu: bulk stats: extend internal collection API
----- Original Message -----
From: "Peter Krempa" <pkrempa(a)redhat.com>
To: "Francesco Romani" <fromani(a)redhat.com>, libvir-list(a)redhat.com
Sent: Tuesday, September 9, 2014 2:14:23 PM
Subject: Re: [libvirt] [PATCH 1/8] qemu: bulk stats: extend internal collection API
On 09/08/14 15:05, Francesco Romani wrote:
> Future patches which will implement more
> bulk stats groups for QEMU will need to access
> the connection object.
>
> To accomodate that, a few changes are needed:
>
> * enrich internal prototype to pass connection object.
> * add per-group flag to mark if one collector needs
> monitor access or not.
> * if at least one collector of the requested stats
> needs monitor access, thus we must start a query job
> for each domain. The specific collectors will
> run nested monitor jobs inside that.
>
> Signed-off-by: Francesco Romani <fromani(a)redhat.com>
> ---
> src/qemu/qemu_driver.c | 51
> ++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 43 insertions(+), 8 deletions(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index d724eeb..2950a4b 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -17338,7 +17339,8 @@ qemuDomainGetStatsState(virDomainObjPtr dom,
>
>
> typedef int
> -(*qemuDomainGetStatsFunc)(virDomainObjPtr dom,
> +(*qemuDomainGetStatsFunc)(virConnectPtr conn,
Looking through the rest of the series. Rather than the complete
connection object you need just the virQEMUDriverPtr for entering the
monitor, but I can live with this.
Since I need to resubmit to address your comments, I'll fix this
to pass just virQEMUDriverPtr.
>
> - if (qemuDomainGetStats(conn, dom, stats, &tmp, flags) < 0)
> + if (needmon && qemuDomainObjBeginJob(driver, dom, QEMU_JOB_QUERY)
> < 0)
> goto cleanup;
>
> - if (tmp)
> - tmpstats[nstats++] = tmp;
> + if ((needmon && virDomainObjIsActive(dom)) || !needmon) {
Hmm this skips offline domains entirely if one of the stats groups needs
the monitor.
I think we should rather skip individual stats groups, or better stats
fields that we can't provide.
Any ideas?
What about this (pseudo-C):
unsigned int privflags = 0;
if (needmon && qemuDomainObjBeginJob(driver, dom, QEMU_JOB_QUERY)
needmon = false;
/* auto disable monitoring, the remainder of the function should be unchanged */
else
privflags |= MONITOR_AVAILABLE;
if ((needmon && virDomainObjIsActive(dom)) || !needmon) {
if (qemuDomainGetStats(conn, dom, stats, &tmp, privflags) < 0)
/* pass monitor availability down the chain. Individual workers will
bail out immediately and silently if they need monitor but it is
not available
*/
goto endjob;
if (tmp)
tmpstats[nstats++] = tmp;
}
No other change should be needed to this patch, and with trivial changes
all the others can be fixed.
--
Francesco Romani
RedHat Engineering Virtualization R & D
Phone: 8261328
IRC: fromani