Re: [libvirt] [PATCH 13/34] qemu: Move and rename qemuProcessDetectVcpuPIDs to qemuDomainDetectVcpuPids

Future patches will tweak and reuse the function in different places so move it separately first. --- src/qemu/qemu_domain.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_domain.h | 2 ++ src/qemu/qemu_process.c | 76 ++------------------------------------------ 3 files changed, 88 insertions(+), 74 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 0fa2dbe..1ea1cd3 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -4257,3 +4257,87 @@ qemuDomainGetVcpuPid(virDomainObjPtr vm, return priv->vcpupids[vcpu]; } + + +/** + * qemuDomainDetectVcpuPIDs: + * @driver: qemu driver data + * @vm: domain object + * @asyncJob: current asynchronous job type + * + * Updates vCPU trhead ids in the private data of @vm.

+ * + * Returns 0 on success -1 on error and reports an appropriate error. + */ +int +qemuDomainDetectVcpuPids(virQEMUDriverPtr driver, + virDomainObjPtr vm, + int asyncJob) +{ + pid_t *cpupids = NULL; + int ncpupids; + qemuDomainObjPrivatePtr priv = vm->privateData; + + /* + * Current QEMU *can* report info about host threads mapped + * to vCPUs, but it is not in a manner we can correctly + * deal with. The TCG CPU emulation does have a separate vCPU + * thread, but it runs every vCPU in that same thread. So it + * is impossible to setup different affinity per thread. + * + * What's more the 'query-cpus' command returns bizarre + * data for the threads. It gives the TCG thread for the + * vCPU 0, but for vCPUs 1-> N, it actually replies with + * the main process thread ID. + * + * The result is that when we try to set affinity for + * vCPU 1, it will actually change the affinity of the + * emulator thread :-( When you try to set affinity for + * vCPUs 2, 3.... it will fail if the affinity was + * different from vCPU 1. + * + * We *could* allow vcpu pinning with TCG, if we made the + * restriction that all vCPUs had the same mask. This would + * at least let us separate emulator from vCPUs threads, as + * we do for KVM. It would need some changes to our cgroups + * CPU layout though, and error reporting for the config + * restrictions. + * + * Just disable CPU pinning with TCG until someone wants + * to try to do this hard work. + */ + if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) { + priv->nvcpupids = 0; + priv->vcpupids = NULL; + return 0; + } + + if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0) + return -1; + ncpupids = qemuMonitorGetCPUInfo(priv->mon, &cpupids); + if (qemuDomainObjExitMonitor(driver, vm) < 0) + return -1; + /* failure to get the VCPU<-> PID mapping or to execute the query + * command will not be treated fatal as some versions of qemu don't + * support this command */ + if (ncpupids <= 0) { + virResetLastError(); + + priv->nvcpupids = 0; + priv->vcpupids = NULL; + return 0; + } + + if (ncpupids != virDomainDefGetVcpus(vm->def)) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("got wrong number of vCPU pids from QEMU monitor. " + "got %d, wanted %d"), + ncpupids, virDomainDefGetVcpus(vm->def)); + VIR_FREE(cpupids); + return -1; + } + + priv->nvcpupids = ncpupids; + priv->vcpupids = cpupids; + return 0; +} diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index 7fc4fff..6a8cf70 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -508,5 +508,7 @@ int qemuDomainDefValidateMemoryHotplug(const virDomainDef *def, bool qemuDomainHasVcpuPids(virDomainObjPtr vm); pid_t qemuDomainGetVcpuPid(virDomainObjPtr vm, unsigned int vcpu); +int qemuDomainDetectVcpuPids(virQEMUDriverPtr driver, virDomainObjPtr vm, + int asyncJob); #endif /* __QEMU_DOMAIN_H__ */ diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index dec4572..a7c3094 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -1962,78 +1962,6 @@ qemuProcessWaitForMonitor(virQEMUDriverPtr driver, return ret; } -static int -qemuProcessDetectVcpuPIDs(virQEMUDriverPtr driver, - virDomainObjPtr vm, int asyncJob) -{ - pid_t *cpupids = NULL; - int ncpupids; - qemuDomainObjPrivatePtr priv = vm->privateData; - - /* - * Current QEMU *can* report info about host threads mapped - * to vCPUs, but it is not in a manner we can correctly - * deal with. The TCG CPU emulation does have a separate vCPU - * thread, but it runs every vCPU in that same thread. So it - * is impossible to setup different affinity per thread. - * - * What's more the 'query-cpus' command returns bizarre - * data for the threads. It gives the TCG thread for the - * vCPU 0, but for vCPUs 1-> N, it actually replies with - * the main process thread ID. - * - * The result is that when we try to set affinity for - * vCPU 1, it will actually change the affinity of the - * emulator thread :-( When you try to set affinity for - * vCPUs 2, 3.... it will fail if the affinity was - * different from vCPU 1. - * - * We *could* allow vcpu pinning with TCG, if we made the - * restriction that all vCPUs had the same mask. This would - * at least let us separate emulator from vCPUs threads, as - * we do for KVM. It would need some changes to our cgroups - * CPU layout though, and error reporting for the config - * restrictions. - * - * Just disable CPU pinning with TCG until someone wants - * to try to do this hard work. - */ - if (vm->def->virtType == VIR_DOMAIN_VIRT_QEMU) { - priv->nvcpupids = 0; - priv->vcpupids = NULL; - return 0; - } - - if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0) - return -1; - ncpupids = qemuMonitorGetCPUInfo(priv->mon, &cpupids); - if (qemuDomainObjExitMonitor(driver, vm) < 0) - return -1; - /* failure to get the VCPU<-> PID mapping or to execute the query - * command will not be treated fatal as some versions of qemu don't - * support this command */ - if (ncpupids <= 0) { - virResetLastError(); - - priv->nvcpupids = 0; - priv->vcpupids = NULL; - return 0; - } - - if (ncpupids != virDomainDefGetVcpus(vm->def)) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("got wrong number of vCPU pids from QEMU monitor. " - "got %d, wanted %d"), - ncpupids, virDomainDefGetVcpus(vm->def)); - VIR_FREE(cpupids); - return -1; - } - - priv->nvcpupids = ncpupids; - priv->vcpupids = cpupids; - return 0; -} - static int qemuProcessDetectIOThreadPIDs(virQEMUDriverPtr driver, @@ -4982,7 +4910,7 @@ qemuProcessLaunch(virConnectPtr conn, goto cleanup; VIR_DEBUG("Detecting VCPU PIDs"); - if (qemuProcessDetectVcpuPIDs(driver, vm, asyncJob) < 0) + if (qemuDomainDetectVcpuPids(driver, vm, asyncJob) < 0) goto cleanup; VIR_DEBUG("Detecting IOThread PIDs"); @@ -5689,7 +5617,7 @@ int qemuProcessAttach(virConnectPtr conn ATTRIBUTE_UNUSED, } VIR_DEBUG("Detecting VCPU PIDs"); - if (qemuProcessDetectVcpuPIDs(driver, vm, QEMU_ASYNC_JOB_NONE) < 0) + if (qemuDomainDetectVcpuPids(driver, vm, QEMU_ASYNC_JOB_NONE) < 0) goto error; VIR_DEBUG("Detecting IOThread PIDs");