Re: [Qemu-devel] [RFC V2 10/10] cpus: reclaim allocated vCPU objects

[Gu Zheng]

Hi Bharata,
On 09/12/2014 04:09 PM, Bharata B Rao wrote:

> On Fri, Sep 12, 2014 at 6:54 AM, Gu Zheng <address@hidden> wrote:
>> Is guest os enabled acpi cpu hotplug? What's the guest's cpu info?
>> Please try latest QEMU, and any feedback is welcome.
>>
> 
> Tried with latest QEMU git + your patchset and Fedora 20 guest, but
> QEMU monitor still shows the removed CPU.
> 
> Guest kernel messages during hotplug:
> 
> address@hidden cpu]# echo 1 > cpu8/online
> [   72.936069] smpboot: Booting Node 0 Processor 8 APIC 0x8
> [    0.003000] kvm-clock: cpu 8, msr 0:7ffc9201, secondary cpu clock
> [   72.950003] TSC synchronization [CPU#0 -> CPU#8]:
> [   72.950003] Measured 199886723309 cycles TSC warp between CPUs,
> turning off TSC clock.
> [   72.950003] tsc: Marking TSC unstable due to check_tsc_sync_source failed
> [   72.972976] KVM setup async PF for cpu 8
> [   72.973648] kvm-stealtime: cpu 8, msr 7d30df00
> [   72.974415] Will online and init hotplugged CPU: 8
> [   72.975307] microcode: CPU8 sig=0x663, pf=0x1, revision=0x1
> 
> Guest kernel messages during hotunplug:
> 
> address@hidden cpu]# [   95.482172] Unregister pv shared memory for cpu 8
> [   95.487169] smpboot: CPU 8 is now offline
> [   95.488667] ACPI: Device does not support D3cold
> 
> 
> Guest cpuinfo (showing for the last CPU only after adding and removing CPU 8)
> 
> processor    : 7
> vendor_id    : GenuineIntel
> cpu family    : 6
> model        : 6
> model name    : QEMU Virtual CPU version 2.1.50
> stepping    : 3
> microcode    : 0x1
> cpu MHz        : 2899.998
> cache size    : 4096 KB
> fpu        : yes
> fpu_exception    : yes
> cpuid level    : 4
> wp        : yes
> flags        : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca
> cmov pse36 clflush mmx fxsr sse sse2 syscall nx lm rep_good nopl pni
> cx16 x2apic popcnt hypervisor lahf_lm
> bogomips    : 5799.99
> clflush size    : 64
> cache_alignment    : 64
> address sizes    : 40 bits physical, 48 bits virtual
> power management:

Guest ejected CPU 8 successfully.
I confirmed it with the same environment as yours, it works well.
Could you please offer your QEMU config and the guest start cmd?
It may help me to investigate the issue.

Thanks,
Gu

> 
> address@hidden boot]# grep -ir hot config-3.11.10-301.fc20.x86_64
> CONFIG_TICK_ONESHOT=y
> # CONFIG_MEMORY_HOTPLUG is not set
> CONFIG_HOTPLUG_CPU=y
> # CONFIG_BOOTPARAM_HOTPLUG_CPU0 is not set
> # CONFIG_DEBUG_HOTPLUG_CPU0 is not set
> CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
> CONFIG_ACPI_HOTPLUG_CPU=y
> CONFIG_HOTPLUG_PCI_PCIE=y
> CONFIG_HOTPLUG_PCI=y
> CONFIG_HOTPLUG_PCI_ACPI=y
> CONFIG_HOTPLUG_PCI_ACPI_IBM=m
> # CONFIG_HOTPLUG_PCI_CPCI is not set
> CONFIG_HOTPLUG_PCI_SHPC=m
> .
>