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qemu: Move and rename qemuProcessDetectVcpuPIDs to qemuDomainDetectVcpuPids

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Future patches will tweak and reuse the function in different places so
move it separately first.
This commit is contained in:
Peter Krempa 2015-12-15 14:45:33 +01:00
parent a190744aa9
commit e97d1d20b1
3 changed files with 88 additions and 74 deletions
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84
src/qemu/qemu_domain.c
View File

@ -4280,3 +4280,87 @@ qemuDomainGetVcpuPid(virDomainObjPtr vm,
return priv->vcpupids[vcpu];
}
/**
* qemuDomainDetectVcpuPids:
* @driver: qemu driver data
* @vm: domain object
* @asyncJob: current asynchronous job type
*
* Updates vCPU thread 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;
}

2
src/qemu/qemu_domain.h
View File

@ -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__ */

76
src/qemu/qemu_process.c
View File

@ -1992,78 +1992,6 @@ 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,
@ -5020,7 +4948,7 @@ 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");
@ -5727,7 +5655,7 @@ 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");