Re: [libvirt] [PATCH v5 4/5] qemu: Add support to pin IOThreads to specific CPU

Add qemuDomainPinIOThread to handle setting the CPU affinity for a specific IOThread Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- include/libvirt/libvirt-domain.h | 9 ++ src/qemu/qemu_driver.c | 221 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 230 insertions(+) diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h index f2f7eb5..11ffd07 100644 --- a/include/libvirt/libvirt-domain.h +++ b/include/libvirt/libvirt-domain.h @@ -3218,6 +3218,15 @@ typedef void (*virConnectDomainEventDeviceRemovedCallback)(virConnectPtr conn, # define VIR_DOMAIN_TUNABLE_CPU_EMULATORPIN "cputune.emulatorpin" /** + * VIR_DOMAIN_TUNABLE_CPU_IOTHREADSPIN: + * + * Macro represents formatted pinning for one IOThread specified by id which is + * appended to the parameter name, for example "cputune.iothreadpin1", + * as VIR_TYPED_PARAM_STRING. + */ +# define VIR_DOMAIN_TUNABLE_CPU_IOTHREADSPIN "cputune.iothreadpin%u" + +/** * VIR_DOMAIN_TUNABLE_CPU_CPU_SHARES: * * Macro represents proportional weight of the scheduler used on the diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index b37474f..aad08b2 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -5780,6 +5780,226 @@ qemuDomainGetIOThreadsInfo(virDomainPtr dom, return ret; } +static int +qemuDomainPinIOThread(virDomainPtr dom, + unsigned int iothread_id, + unsigned char *cpumap, + int maplen, + unsigned int flags) +{ + if (virDomainPinIOThreadEnsureACL(dom->conn, vm->def, flags) < 0) + goto cleanup; + + if (!(caps = virQEMUDriverGetCapabilities(driver, false))) + goto cleanup; + + if (vm->def->placement_mode == VIR_DOMAIN_CPU_PLACEMENT_MODE_AUTO) { + virReportError(VIR_ERR_OPERATION_INVALID, "%s", + _("Changing affinity for IOThread dynamically is " + "not allowed when CPU placement is 'auto'")); + goto cleanup; + } + + if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) + goto cleanup; + + if (virDomainLiveConfigHelperMethod(caps, driver->xmlopt, vm, &flags, + &persistentDef) < 0) + goto endjob; + + if (flags & VIR_DOMAIN_AFFECT_LIVE) + persistentDef = vm->def; + + /* Coverity didn't realize that targetDef must be set if we got here. */ + sa_assert(persistentDef); + + if (!(pcpumap = virBitmapNewData(cpumap, maplen))) + goto endjob; + + if (virBitmapIsAllClear(pcpumap)) { + virReportError(VIR_ERR_INVALID_ARG, "%s", + _("Empty iothread cpumap list for pinning")); + goto endjob; + } + + /* pinning to all physical cpus means resetting,

+ * so check if we can reset setting. + */ + if (virBitmapIsAllSet(pcpumap)) + doReset = true; + + if (flags & VIR_DOMAIN_AFFECT_LIVE) { + + if (priv->iothreadpids == NULL) { + virReportError(VIR_ERR_OPERATION_INVALID, + "%s", _("IOThread affinity is not supported")); + goto endjob; + } + + if (iothread_id > priv->niothreadpids) { + virReportError(VIR_ERR_INVALID_ARG, + _("iothread value out of range %d > %d"), + iothread_id, priv->niothreadpids); + goto endjob; + } + + if (vm->def->cputune.iothreadspin) { + /* The VcpuPinDefCopy works for IOThreads too */