On Mon, Jun 22, 2015 at 17:06:46 -0600, Eric Blake wrote: > Time to wire up the new API to call into the QMP command for setting > a write threshold. > > For now, the API only allows setting the threshold on the active > layer. But I left TODOs in the series for places that need > touching to find and support node names of backing files, so that > we can use "vda[1]" notation to register for a threshold on the > backing image during an active commit operation. > > * src/qemu/qemu_driver.c (qemuDomainBlockSetWriteThreshold): New > function. > * src/qemu/qemu_monitor.c (qemuMonitorBlockSetWriteThreshold): > Likewise. > * src/qemu/qemu_monitor.h (qemuMonitorBlockSetWriteThreshold): > Likewise. > * src/qemu/qemu_monitor_json.c > (qemuMonitorJSONBlockSetWriteThreshold): Likewise. > * src/qemu/qemu_monitor_json.h > (qemuMonitorJSONBlockSetWriteThreshold): Likewise. > > Signed-off-by: Eric Blake <[email protected]> > --- > src/qemu/qemu_driver.c | 95 > ++++++++++++++++++++++++++++++++++++++++++++ > src/qemu/qemu_monitor.c | 13 ++++++ > src/qemu/qemu_monitor.h | 5 +++ > src/qemu/qemu_monitor_json.c | 30 ++++++++++++++ > src/qemu/qemu_monitor_json.h | 3 ++ > 5 files changed, 146 insertions(+) > > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > index 72e256b..732f102 100644 > --- a/src/qemu/qemu_driver.c > +++ b/src/qemu/qemu_driver.c > @@ -17906,6 +17906,100 @@ qemuDomainGetBlockIoTune(virDomainPtr dom, > return ret; > } > > + > +static int > +qemuDomainBlockSetWriteThreshold(virDomainPtr dom, > + const char *path, > + unsigned long long threshold, > + unsigned int flags) > +{ > + virQEMUDriverPtr driver = dom->conn->privateData; > + virDomainObjPtr vm = NULL; > + qemuDomainObjPrivatePtr priv; > + virDomainDiskDefPtr disk = NULL; > + virCapsPtr caps = NULL; > + virQEMUDriverConfigPtr cfg = NULL; > + const char *node = NULL; > + int ret = -1; > + > + virCheckFlags(VIR_DOMAIN_BLOCK_SET_WRITE_THRESHOLD_PROPORTION, -1); > + > + if (!(vm = qemuDomObjFromDomain(dom))) > + return -1; > + priv = vm->privateData; > + > + if (virDomainBlockSetWriteThresholdEnsureACL(dom->conn, vm->def) < 0) > + goto cleanup; > + > + if (!(caps = virQEMUDriverGetCapabilities(driver, false))) > + goto cleanup; > + if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCK_WRITE_THRESHOLD) || > + !virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_AUTO_NODE_NAMES)) { > + virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s", > + _("block write threshold not supported by this " > + "qemu binary")); > + goto cleanup; > + } > + > + if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) > + goto cleanup; > + > + if (!virDomainObjIsActive(vm)) { > + virReportError(VIR_ERR_OPERATION_INVALID, > + "%s", _("domain is not running")); > + goto endjob; > + } > + > + if (!(disk = virDomainDiskByName(vm->def, path, false))) { > + virReportError(VIR_ERR_INVALID_ARG, > + _("invalid path %s not assigned to domain"), path); > + goto endjob; > + } > + > + if (!(node = qemuDomainDiskGetAllocationNode(driver, vm, disk))) { > + virReportError(VIR_ERR_INVALID_ARG, > + _("cannot track threshold events on disk '%s'"), > + path); > + goto endjob; > + } > + > + cfg = virQEMUDriverGetConfig(driver); > + if (qemuStorageLimitsRefresh(driver, cfg, vm, disk->src) < 0)
This function begins with a rather long comment explaining that it's not
entirely a good idea to use it on online VMs and especially on
write-enabled disk sources. Shouldn't we query the monitor rather than
use that?
> + goto endjob;
> +
> + if (flags & VIR_DOMAIN_BLOCK_SET_WRITE_THRESHOLD_PROPORTION) {
> + /* Caller already sanitized max value to 1000000. Use of
> + * floating point intermediary reduces (but does not
> + * eliminate) rounding error, but since we already document a
> + * granularity of parts per million, it shouldn't matter too
> + * much if the answer is a few bytes off. */
> + threshold *= disk->src->physical / 1e6;
> + } else {
> + if (threshold > disk->src->physical) {
> + virReportError(VIR_ERR_INVALID_ARG,
> + _("threshold %llu exceeds disk size %llu"),
> + threshold, disk->src->physical);
> + goto endjob;
> + }
> + }
> +
> + qemuDomainObjEnterMonitor(driver, vm);
> + ret = qemuMonitorBlockSetWriteThreshold(priv->mon, node, threshold);
> + if (qemuDomainObjExitMonitor(driver, vm) < 0)
> + ret = -1;
> +
> +
> + endjob:
> + qemuDomainObjEndJob(driver, vm);
> +
> + cleanup:
> + virDomainObjEndAPI(&vm);
> + virObjectUnref(caps);
> + virObjectUnref(cfg);
> + return ret;
> +}
> +
> +
> static int
> qemuDomainGetDiskErrors(virDomainPtr dom,
> virDomainDiskErrorPtr errors,
> @@ -20037,6 +20131,7 @@ static virHypervisorDriver qemuHypervisorDriver = {
> .nodeSuspendForDuration = qemuNodeSuspendForDuration, /* 0.9.8 */
> .domainSetBlockIoTune = qemuDomainSetBlockIoTune, /* 0.9.8 */
> .domainGetBlockIoTune = qemuDomainGetBlockIoTune, /* 0.9.8 */
> + .domainBlockSetWriteThreshold = qemuDomainBlockSetWriteThreshold, /*
> 1.3.0 */
> .domainSetNumaParameters = qemuDomainSetNumaParameters, /* 0.9.9 */
> .domainGetNumaParameters = qemuDomainGetNumaParameters, /* 0.9.9 */
> .domainGetInterfaceParameters = qemuDomainGetInterfaceParameters, /*
> 0.9.9 */
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index c4b6073..2ff34e2 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -1866,6 +1866,19 @@ qemuMonitorBlockStatsUpdateThreshold(qemuMonitorPtr
> mon,
>
>
> int
> +qemuMonitorBlockSetWriteThreshold(qemuMonitorPtr mon,
> + const char *dev_name,
This function needs a node name passed so it should also be called that
way to avoid confusion since the function lacks docs.
> + unsigned long long threshold)
> +{
> + VIR_DEBUG("dev_name=%s, threshold=%llu", dev_name, threshold);
> +
> + QEMU_CHECK_MONITOR_JSON(mon);
> +
> + return qemuMonitorJSONBlockSetWriteThreshold(mon, dev_name, threshold);
> +}
> +
> +
> +int
> qemuMonitorGetBlockExtent(qemuMonitorPtr mon,
> const char *dev_name,
> unsigned long long *extent)
Peter
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