Bug 581764
| Summary: | memory reported as used (by SwapCache and by Cache) though no process holds it. | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 5 | Reporter: | RHEL Program Management <pm-rhel> |
| Component: | kvm | Assignee: | Virtualization Maintenance <virt-maint> |
| Status: | CLOSED ERRATA | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | low | Docs Contact: | |
| Priority: | high | ||
| Version: | 5.5 | CC: | aarcange, apevec, danken, ehabkost, gleb, iheim, khong, llim, lwang, lwoodman, michen, mkenneth, plyons, pm-eus, riel, tburke, virt-maint, ykaul |
| Target Milestone: | rc | Keywords: | ZStream |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | kvm-83-164.el5_5.6 | Doc Type: | Bug Fix |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2010-05-18 08:07:23 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 575585 | ||
| Bug Blocks: | 556823 | ||
|
Description
RHEL Program Management
2010-04-13 07:49:57 UTC
Summary:
PASS. Reproduced in kvm-83-164.el5_5.2 and verified in kvm-83-164.el5_5.6
Host environment:
processor : 0
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : AMD Phenom(tm) 9600B Quad-Core Processor
stepping : 3
cpu MHz : 1200.000
cache size : 512 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc nonstop_tsc pni cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy altmovcr8 abm sse4a misalignsse 3dnowprefetch osvw
...
Mem: 8G
CLI:
/usr/libexec/qemu-kvm -m 8G -smp 1 -drive file=/mnt/win2008-64.qcow2,if=ide,cache=off -net nic,model=e1000,vlan=1,macaddr=02:00:40:3F:20:10 -net tap,vlan=1,script=/etc/qemu-ifup -boot c -uuid 17544ecc-d3a1-4d3c-a386-12daf50015f1 -usbdevice tablet -no-hpet -rtc-td-hack -no-kvm-pit-reinjection -monitor stdio -notify all -cpu qemu64,+sse2 -balloon none -startdate now -vnc :11 -name 175-test1 -M rhel5.5.0
Setup:
Prepare two 64bit Windows guests (In case host has large memory, 64bit guest can support memory size above 4G).
Steps:
1. reboot host to provide a clean environment (SwapCached: 0 kB)
2. start ksm scanner (e.g. pages_to_scan 5000, sleep_time 5000)
# ksmctl 5000 5000
3. start two Windows guests in parallel, each with large memory (e.g. equal to the physical memory size of the host ).
# /usr/libexec/qemu-kvm -m 8G -smp 1 -drive file=/mnt/win2008-64.qcow2 ...
# /usr/libexec/qemu-kvm -m 8G -smp 1 -drive file=/mnt/win2008-64.qcow2.2 ...
4. wait till pages shared by two guests become relatively stable (RES, SHR columns)
# top
...
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1830 root 20 -5 0 0 0 R 79.4 0.0 6:16.39 kksmd
4357 root 15 0 8426m 4.5g 4.3g S 2.0 59.5 2:45.67 qemu-kvm
4372 root 15 0 8426m 2.6g 2.4g S 0.7 34.9 3:40.03 qemu-kvm
5. check host Swap Cache
# grep Swap /proc/meminfo
6. shut down both Windows guests.
7. check host Swap Cache again.
Results after step 7:
1. kvm-83-164.el5_5.2
free -m
total used free shared buffers cached
Mem: 7718 1879 5839 0 2 16
-/+ buffers/cache: 1860 5858
Swap: 9727 1835 7892
# grep Swap /proc/meminfo
SwapCached: 1829152 kB
SwapTotal: 9961464 kB
SwapFree: 8082072 kB
2. kvm-83-164.el5_5.6
# free -m
total used free shared buffers cached
Mem: 7718 916 6802 0 25 798
-/+ buffers/cache: 92 7626
Swap: 9727 79 9648
[root@dhcp-91-175 ~]# grep Swap /proc/meminfo
SwapCached: 6152 kB
SwapTotal: 9961464 kB
SwapFree: 9879556 kB
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2010-0419.html |