Bug 1298204
| Summary: | tuned: race condition when generating modprobe file | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Jan Kurik <jkurik> |
| Component: | tuned | Assignee: | Jaroslav Škarvada <jskarvad> |
| Status: | CLOSED ERRATA | QA Contact: | Tereza Cerna <tcerna> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | high | ||
| Version: | 7.3 | CC: | bhu, hhuang, jeder, jen, jskarvad, juzhang, lcapitulino, peterx, tcerna |
| Target Milestone: | rc | Keywords: | Patch, ZStream |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | tuned-2.5.1-4.el7.2 | Doc Type: | Bug Fix |
| Doc Text: |
Cause:
Previously there existed race condition in realtime-virtual-host Tuned profile.
Consequence:
The modprobe configuration file for KVM RT could be generated after the KVM modules are loaded causing the modules options to be not used. This can result in latency spike. The modprobe configuration file was (re)generated on each Tuned start (machine boot) and profile activation which increased the probability that the race condition will be triggered.
Fix:
Tuned code was extended to provide hint to profiles why it executes "stop" callback and the realtime-virtual-host profile was updated to use this hint and conditionally generate the modprobe configuration file only when the profile is activated (selected).
Result:
Now the modprobe configuration file is generated only when the realtime-virtual-host profile is activated (selected). The profile activation needs to be followed by machine reboot. During the reboot the modprobe configuration file is not (re)generated again which removes the race condition.
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Story Points: | --- |
| Clone Of: | 1292117 | Environment: | |
| Last Closed: | 2016-02-16 11:18:41 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: | 1292117 | ||
| Bug Blocks: | |||
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Description
Jan Kurik
2016-01-13 13:32:07 UTC
Verified in tuned-2.5.1-4.el7_2.2 - PASS :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :: [ LOG ] :: Test :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :: [ PASS ] :: Command 'systemctl restart tuned' (Expected 0, got 0) :: [ PASS ] :: Command 'journalctl -b | grep -q "profile_switch"' (Expected 1, got 1) :: [ PASS ] :: Command 'tuned-adm profile test' (Expected 0, got 0) :: [ PASS ] :: Command 'journalctl -b | grep -q "profile_switch"' (Expected 0, got 0) :: [ PASS ] :: RESULT: Test _______________________________________________________________ Reproduced in tuned-2.5.1-4.el7 - FAIL :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :: [ LOG ] :: Test :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :: [ PASS ] :: Command 'systemctl restart tuned' (Expected 0, got 0) :: [ PASS ] :: Command 'journalctl -b | grep -q "profile_switch"' (Expected 1, got 1) :: [ PASS ] :: Command 'tuned-adm profile test' (Expected 0, got 0) :: [ FAIL ] :: Command 'journalctl -b | grep -q "profile_switch"' (Expected 0, got 1) :: [ FAIL ] :: RESULT: Test 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://rhn.redhat.com/errata/RHBA-2016-0213.html |