Bug 1099836
| Summary: | the vcpupin info is not sync with the qemu process after hot-unplug and hot-plug vcpus | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Xuesong Zhang <xuzhang> |
| Component: | libvirt | Assignee: | Ján Tomko <jtomko> |
| Status: | CLOSED WONTFIX | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 6.6 | CC: | acathrow, dyuan, honzhang, jmiao, mzhan |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2014-06-02 16:01:26 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Patch sent upstream: https://www.redhat.com/archives/libvir-list/2014-May/msg00836.html This is just a cosmetic issue (pinning the re-plugged vcpus manually works) and I don't think it's worth fixing. Upstream QEMU doesn't support hot-unplug of VCPUs, so the proposed patch is not as useful (and it made assumptions about QEMU behavior that might not be true when hot-unplug will be supported). Also, hot-unplugging pinned vcpus would crash libvirtd until recently (bug 1088165) and vcpu hot-unplug does not seem to be supported in RHEL6: https://bugzilla.redhat.com/show_bug.cgi?id=1088216#c8 |
Description of problem: Pin all the vcpus of guest to specific host cpu, hot-unplug some vcpus, hot-plug the vcpus back, the vcpupin info is not sync with the info of qemu process. Version-Release number of selected component (if applicable): libvirt-0.10.2-36.el6.x86_64 qemu-kvm-rhev-0.12.1.2-2.426.el6.x86_64 kernel-2.6.32-466.el6.x86_64 How reproducible: 100% Steps to Reproduce: １． prepare one guest, let all the vcpus are pinned to some host cpus, such as the following one: # virsh dumpxml rhel6.5|grep cpu <vcpu placement='static'>4</vcpu> <cputune> <vcpupin vcpu='0' cpuset='1'/> <vcpupin vcpu='1' cpuset='1'/> <vcpupin vcpu='2' cpuset='1'/> <vcpupin vcpu='3' cpuset='1'/> </cputune> 2. start the guest # virsh start rhel6.5 Domain rhel6.5 started 3. check pid the qemu process, make sure all the vcpus are all pinned to the host cpu. # ps -ef|grep qemu qemu 3961 1 75 04:15 ? 00:00:21 /usr/libexec/qemu-kvm -name rhel6.5 ...... # grep Cpus_allowed_list /proc/3961/task/*/status /proc/3961/task/3961/status:Cpus_allowed_list: 0-3 /proc/3961/task/3982/status:Cpus_allowed_list: 0-3 /proc/3961/task/3983/status:Cpus_allowed_list: 1 /proc/3961/task/3984/status:Cpus_allowed_list: 1 /proc/3961/task/3985/status:Cpus_allowed_list: 1 /proc/3961/task/3986/status:Cpus_allowed_list: 1 4. all the vcpus are all pinned to one host cpu. # virsh vcpupin rhel6.5 VCPU: CPU Affinity ---------------------------------- 0: 1 1: 1 2: 1 3: 1 5. hot-unplug vcpus # virsh setvcpus rhel6.5 2 # virsh vcpupin rhel6.5 VCPU: CPU Affinity ---------------------------------- 0: 1 1: 1 6. hot-plug the vcpus back # virsh setvcpus rhel6.5 4 7. check the vcpupin info, the new hot-plugged vcpus are pinned to all the host cpus. # virsh vcpupin rhel6.5 VCPU: CPU Affinity ---------------------------------- 0: 1 1: 1 2: 0-3 3: 0-3 8, check the qemu proces, the new hot-plugged vcpus are still pinned to the host CPU1 # grep Cpus_allowed_list /proc/3961/task/*/status /proc/3961/task/3961/status:Cpus_allowed_list: 0-3 /proc/3961/task/3982/status:Cpus_allowed_list: 0-3 /proc/3961/task/3983/status:Cpus_allowed_list: 1 /proc/3961/task/3984/status:Cpus_allowed_list: 1 /proc/3961/task/3985/status:Cpus_allowed_list: 1 Actually results: As step7 and 8, the step7 shows that the new hot-plugged vcpu are pinned to all host cpus, but the step 8 shows that the new hot-plugged vcpu are still pinned to the host CPU1. Expected results: The vcpu pinned info should be kept same in step 7 and 8.