Bug 1690122
| Summary: | RFE: backport upstream patches for polling buffers/caches from balloon driver | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Tomáš Golembiovský <tgolembi> |
| Component: | libvirt | Assignee: | Tomáš Golembiovský <tgolembi> |
| Status: | CLOSED ERRATA | QA Contact: | Luyao Huang <lhuang> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | high | ||
| Version: | 7.6 | CC: | dyuan, jdenemar, jiyan, jsuchane, lmen, mtessun, xuzhang, yalzhang |
| Target Milestone: | rc | Keywords: | FutureFeature |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | libvirt-4.5.0-12.el7 | Doc Type: | If docs needed, set a value |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2019-08-06 13:14:44 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: | |||
Verify this bug with libvirt-4.5.0-18.el7.x86_64:
S1: verify dommemstat show right disk cache for RHEL8 guest
1. prepare a RHEL8 guest with memballoon and set stats period
# virsh dumpxml vm1
...
<memballoon model='virtio'>
<stats period='2'/>
<alias name='balloon0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</memballoon>
...
2. use dommemstat command to get disk caches:
# virsh dommemstat vm1
actual 1024000
swap_in 0
swap_out 0
major_fault 1030
minor_fault 1379325
unused 398668
available 815476
usable 534064
last_update 1559112601
disk_caches 238180
rss 739004
3. verify disk caches value in guest:
IN GUEST:
# cat /proc/meminfo
MemTotal: 815476 kB
MemFree: 398712 kB
MemAvailable: 534108 kB
Buffers: 3164 kB
Cached: 235016 kB
SwapCached: 0 kB
...
from kernel commit: Buffers + Cached + SwapCached = disk_caches
S2: verify there is no disk cache data in dommemstat output for RHEL7/RHEL6 guest
1. prepare a RHEL7/RHEL6 guest with memballoon and set stats period
# virsh dumpxml vm1
...
<memballoon model='virtio'>
<stats period='2'/>
<alias name='balloon0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</memballoon>
...
2. check dommemstat command output and there is no disk_caches:
# virsh dommemstat vm1
actual 1024000
swap_in 0
swap_out 0
major_fault 580
minor_fault 466748
unused 761048
available 989464
usable 740912
last_update 1559112942
rss 437452
3. check libvirtd debug log and make sure qemu return stat-disk-caches is -1 (18446744073709551615):
2019-05-29 06:55:43.473+0000: 23060: debug : qemuMonitorJSONIOProcessLine:197 : Line [{"return": {"stats": {"stat-swap-out": 0, "stat-available-memory": 758693888, "stat-free-memory": 779313152, "stat-minor-faults": 466748, "stat-major-faults": 580, "stat-total-memory": 1013211136, "stat-swap-in": 0, "stat-disk-caches": 18446744073709551615}, "last-update": 1559112942}, "id": "libvirt-16"}]
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2019:2294 |
Would it be possible to backport patch for polling disk_caches balloon stat (i.e. buffers/caches) from QEMU? The relevant commit is: aee046550893e7c0e5ccb4861dd3f0715d31eeb7 from libvirt 4.6.0 Since RHV will be still on EL7 for some time it would be helpful to have that so we can fetch the info from EL8 guests.