Re: [libvirt] [PATCHv3 10/10] threshold: add write threshold setting in qemu

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 <eblake(a)redhat.com&gt; --- 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)

+ 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,

+ 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)