[libvirt] [PATCH 19/34] qemu: Split up vCPU hotplug and hotunplug
Peter Krempa
pkrempa at redhat.com
Fri Nov 20 15:22:09 UTC 2015
There's only very little common code among the two operations. Split the
functions so that the internals are easier to understand and refactor
later.
---
src/qemu/qemu_driver.c | 210 ++++++++++++++++++++++++++++++++-----------------
1 file changed, 136 insertions(+), 74 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 72879cf..a483220 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4710,31 +4710,15 @@ qemuDomainHotplugVcpus(virQEMUDriverPtr driver,
qemuDomainObjEnterMonitor(driver, vm);
- /* We need different branches here, because we want to offline
- * in reverse order to onlining, so any partial fail leaves us in a
- * reasonably sensible state */
- if (nvcpus > vcpus) {
- for (i = vcpus; i < nvcpus; i++) {
- /* Online new CPU */
- rc = qemuMonitorSetCPU(priv->mon, i, true);
- if (rc == 0)
- goto unsupported;
- if (rc < 0)
- goto exit_monitor;
-
- vcpus++;
- }
- } else {
- for (i = vcpus - 1; i >= nvcpus; i--) {
- /* Offline old CPU */
- rc = qemuMonitorSetCPU(priv->mon, i, false);
- if (rc == 0)
- goto unsupported;
- if (rc < 0)
- goto exit_monitor;
+ for (i = vcpus; i < nvcpus; i++) {
+ /* Online new CPU */
+ rc = qemuMonitorSetCPU(priv->mon, i, true);
+ if (rc == 0)
+ goto unsupported;
+ if (rc < 0)
+ goto exit_monitor;
- vcpus--;
- }
+ vcpus++;
}
/* hotplug succeeded */
@@ -4755,15 +4739,6 @@ qemuDomainHotplugVcpus(virQEMUDriverPtr driver,
goto cleanup;
}
- /* check if hotplug has failed */
- if (vcpus < oldvcpus && ncpupids == oldvcpus) {
- virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
- _("qemu didn't unplug the vCPUs properly"));
- vcpus = oldvcpus;
- ret = -1;
- goto cleanup;
- }
-
if (ncpupids != vcpus) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("got wrong number of vCPU pids from QEMU monitor. "
@@ -4781,50 +4756,37 @@ qemuDomainHotplugVcpus(virQEMUDriverPtr driver,
&mem_mask, -1) < 0)
goto cleanup;
- if (nvcpus > oldvcpus) {
- for (i = oldvcpus; i < nvcpus; i++) {
- if (priv->cgroup) {
- cgroup_vcpu =
- qemuDomainAddCgroupForThread(priv->cgroup,
- VIR_CGROUP_THREAD_VCPU,
- i, mem_mask,
- cpupids[i]);
- if (!cgroup_vcpu)
- goto cleanup;
- }
+ for (i = oldvcpus; i < nvcpus; i++) {
+ if (priv->cgroup) {
+ cgroup_vcpu =
+ qemuDomainAddCgroupForThread(priv->cgroup,
+ VIR_CGROUP_THREAD_VCPU,
+ i, mem_mask,
+ cpupids[i]);
+ if (!cgroup_vcpu)
+ goto cleanup;
+ }
- /* Inherit def->cpuset */
- if (vm->def->cpumask) {
- if (qemuDomainHotplugAddPin(vm->def->cpumask, i,
- &vm->def->cputune.vcpupin,
- &vm->def->cputune.nvcpupin) < 0) {
- ret = -1;
- goto cleanup;
- }
- if (qemuDomainHotplugPinThread(vm->def->cpumask, i, cpupids[i],
- cgroup_vcpu) < 0) {
- ret = -1;
- goto cleanup;
- }
+ /* Inherit def->cpuset */
+ if (vm->def->cpumask) {
+ if (qemuDomainHotplugAddPin(vm->def->cpumask, i,
+ &vm->def->cputune.vcpupin,
+ &vm->def->cputune.nvcpupin) < 0) {
+ ret = -1;
+ goto cleanup;
}
- virCgroupFree(&cgroup_vcpu);
-
- if (qemuProcessSetSchedParams(i, cpupids[i],
- vm->def->cputune.nvcpusched,
- vm->def->cputune.vcpusched) < 0)
+ if (qemuDomainHotplugPinThread(vm->def->cpumask, i, cpupids[i],
+ cgroup_vcpu) < 0) {
+ ret = -1;
goto cleanup;
+ }
}
- } else {
- for (i = oldvcpus - 1; i >= nvcpus; i--) {
- if (qemuDomainDelCgroupForThread(priv->cgroup,
- VIR_CGROUP_THREAD_VCPU, i) < 0)
- goto cleanup;
+ virCgroupFree(&cgroup_vcpu);
- /* Free vcpupin setting */
- virDomainPinDel(&vm->def->cputune.vcpupin,
- &vm->def->cputune.nvcpupin,
- i);
- }
+ if (qemuProcessSetSchedParams(i, cpupids[i],
+ vm->def->cputune.nvcpusched,
+ vm->def->cputune.vcpusched) < 0)
+ goto cleanup;
}
priv->nvcpupids = ncpupids;
@@ -4853,6 +4815,101 @@ qemuDomainHotplugVcpus(virQEMUDriverPtr driver,
static int
+qemuDomainHotunplugVcpus(virQEMUDriverPtr driver,
+ virDomainObjPtr vm,
+ unsigned int nvcpus)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ size_t i;
+ int rc = 1;
+ int ret = -1;
+ int oldvcpus = virDomainDefGetVCpus(vm->def);
+ int vcpus = oldvcpus;
+ pid_t *cpupids = NULL;
+ int ncpupids;
+
+ qemuDomainObjEnterMonitor(driver, vm);
+
+ for (i = vcpus - 1; i >= nvcpus; i--) {
+ /* Offline old CPU */
+ rc = qemuMonitorSetCPU(priv->mon, i, false);
+ if (rc == 0)
+ goto unsupported;
+ if (rc < 0)
+ goto exit_monitor;
+
+ vcpus--;
+ }
+
+ ret = 0;
+
+ /* After hotplugging the CPUs we need to re-detect threads corresponding
+ * to the virtual CPUs. Some older versions don't provide the thread ID
+ * or don't have the "info cpus" command (and they don't support multiple
+ * CPUs anyways), so errors in the re-detection will not be treated
+ * fatal */
+ if ((ncpupids = qemuMonitorGetCPUInfo(priv->mon, &cpupids)) <= 0) {
+ virResetLastError();
+ goto exit_monitor;
+ }
+ if (qemuDomainObjExitMonitor(driver, vm) < 0) {
+ ret = -1;
+ goto cleanup;
+ }
+
+ /* check if hotunplug has failed */
+ if (ncpupids == oldvcpus) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("qemu didn't unplug the vCPUs properly"));
+ vcpus = oldvcpus;
+ ret = -1;
+ goto cleanup;
+ }
+
+ if (ncpupids != vcpus) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("got wrong number of vCPU pids from QEMU monitor. "
+ "got %d, wanted %d"),
+ ncpupids, vcpus);
+ vcpus = oldvcpus;
+ ret = -1;
+ goto cleanup;
+ }
+
+ for (i = oldvcpus - 1; i >= nvcpus; i--) {
+ if (qemuDomainDelCgroupForThread(priv->cgroup,
+ VIR_CGROUP_THREAD_VCPU, i) < 0)
+ goto cleanup;
+
+ /* Free vcpupin setting */
+ virDomainPinDel(&vm->def->cputune.vcpupin,
+ &vm->def->cputune.nvcpupin,
+ i);
+ }
+
+ priv->nvcpupids = ncpupids;
+ VIR_FREE(priv->vcpupids);
+ priv->vcpupids = cpupids;
+ cpupids = NULL;
+
+ cleanup:
+ VIR_FREE(cpupids);
+ if (virDomainObjIsActive(vm) &&
+ virDomainDefSetVCpus(vm->def, vcpus) < 0)
+ ret = -1;
+ virDomainAuditVcpu(vm, oldvcpus, nvcpus, "update", rc == 1);
+ return ret;
+
+ unsupported:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("cannot change vcpu count of this domain"));
+ exit_monitor:
+ ignore_value(qemuDomainObjExitMonitor(driver, vm));
+ goto cleanup;
+}
+
+
+static int
qemuDomainSetVcpusAgent(virDomainObjPtr vm,
unsigned int nvcpus)
{
@@ -4985,8 +5042,13 @@ qemuDomainSetVcpusFlags(virDomainPtr dom, unsigned int nvcpus,
}
if (def) {
- if (qemuDomainHotplugVcpus(driver, vm, nvcpus) < 0)
- goto endjob;
+ if (nvcpus > virDomainDefGetVCpus(def)) {
+ if (qemuDomainHotplugVcpus(driver, vm, nvcpus) < 0)
+ goto endjob;
+ } else {
+ if (qemuDomainHotunplugVcpus(driver, vm, nvcpus) < 0)
+ goto endjob;
+ }
if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0)
goto endjob;
--
2.6.2
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