[Qemu-devel] OOM don't like qemu-kvm

[Peter Cheung]

Hi All

    My compuer is i7 with 32 GB ram without swap, i try to launch 28 vm with 1GB ram each, it runs smoothly.

If I launch 64 VMs, after the VMs eat up all the memory, the linux hang. If the linux is lack of memory, the OOM will try to kill process, right? And the OOM should pick those qemu-kvm processes to kill, but seems the OOM don't pick qemu-kvm or the OOM failed to kill qemu-kvm processes.

    If I turn on swap, although 64 VMs with 1GB ram each will make my computer very slow, but at least it won't hang.

Can anybody explain this?

below is my computer information:

CPUinfo:

/root>cat /proc/cpuinfo 

processor : 0

vendor_id : GenuineIntel

cpu family : 6

model : 58

model name : Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz

stepping : 9

microcode : 0x13

cpu MHz : 3501.000

cache size : 8192 KB

physical id : 0

siblings : 8

core id : 0

cpu cores : 4

apicid : 0

initial apicid : 0

fpu : yes

fpu_exception : yes

cpuid level : 13

wp : yes

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase smep erms

bogomips : 7000.26

clflush size : 64

cache_alignment : 64

address sizes : 36 bits physical, 48 bits virtual

power management:

/root>free -m

             total       used       free     shared    buffers     cached

Mem:         32133      25910       6222          0        263       3062

-/+ buffers/cache:      22583       9549

Swap:            0          0          0

/root>uname -a

Linux localhost.localdomain 3.7.2-204.fc18.x86_64 #1 SMP Wed Jan 16 16:22:52 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

/root>rpm -qa|grep qemu

libvirt-daemon-driver-qemu-0.10.2.3-1.fc18.x86_64

qemu-system-m68k-1.2.2-4.fc18.x86_64

qemu-common-1.2.2-4.fc18.x86_64

qemu-system-unicore32-1.2.2-4.fc18.x86_64

ipxe-roms-qemu-20120328-2.gitaac9718.fc18.noarch

qemu-system-sh4-1.2.2-4.fc18.x86_64

qemu-kvm-1.2.2-4.fc18.x86_64

qemu-system-arm-1.2.2-4.fc18.x86_64

qemu-system-s390x-1.2.2-4.fc18.x86_64

qemu-user-1.2.2-4.fc18.x86_64

qemu-1.2.2-4.fc18.x86_64

qemu-system-microblaze-1.2.2-4.fc18.x86_64

qemu-system-mips-1.2.2-4.fc18.x86_64

qemu-system-xtensa-1.2.2-4.fc18.x86_64

qemu-system-ppc-1.2.2-4.fc18.x86_64

qemu-img-1.2.2-4.fc18.x86_64

qemu-system-alpha-1.2.2-4.fc18.x86_64

qemu-system-sparc-1.2.2-4.fc18.x86_64

qemu-system-lm32-1.2.2-4.fc18.x86_64

libvirt-daemon-qemu-0.10.2.3-1.fc18.x86_64

qemu-system-or32-1.2.2-4.fc18.x86_64

qemu-system-cris-1.2.2-4.fc18.x86_64

qemu-system-x86-1.2.2-4.fc18.x86_64

/root>rpm -qa|grep kvm

libvirt-daemon-kvm-0.10.2.3-1.fc18.x86_64

qemu-kvm-1.2.2-4.fc18.x86_64

Thanks

from Peter