Bug 433956
Summary: | [MRG] 2.6.24.1-21 kernel uses | ||
---|---|---|---|
Product: | Red Hat Enterprise MRG | Reporter: | IBM Bug Proxy <bugproxy> |
Component: | realtime-kernel | Assignee: | Red Hat Real Time Maintenance <rt-maint> |
Status: | CLOSED NOTABUG | QA Contact: | |
Severity: | medium | Docs Contact: | |
Priority: | low | ||
Version: | beta | ||
Target Milestone: | --- | ||
Target Release: | --- | ||
Hardware: | x86_64 | ||
OS: | All | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2008-03-11 14:29:44 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: |
Description
IBM Bug Proxy
2008-02-22 12:08:16 UTC
------- Comment From dvhltc.com 2008-02-25 20:01 EDT------- I checked our SR3 kernel, and it has IRQ- naming, not IRQ_. [root@elm3b207 ~]# ps aux | grep IRQ root 102 0.0 0.0 0 0 ? S< 13:05 0:00 [IRQ-11] root 329 0.0 0.0 0 0 ? S< 13:05 0:00 [IRQ-8] ... [root@elm3b207 ~]# uname -r 2.6.21.4-ibmrt1.23 Checking the set_kthread_prio script, I see that the regex's do indeed search for ^IRQ_. Checking the IRQ threads revealed that NONE of them were running with realtime priority! [root@elm3b207 ~]# ps -eLo rtprio,comm | grep IRQ - IRQ-11 - IRQ-8 - IRQ-12 - IRQ-1 - IRQ-3 - IRQ-19 - IRQ-26 - IRQ-6 - IRQ-25 - IRQ-4 This is all on a fresh R1-SR3.dat deploy. ------- Comment From dvhltc.com 2008-02-25 20:38 EDT------- So from patch-2.6.21.4-rt10 we see: +static int start_irq_thread(int irq, struct irq_desc *desc) +{ + if (desc->thread || !ok_to_create_irq_threads) + return 0; + + desc->thread = kthread_create(do_irqd, desc, "IRQ-%d", irq); and from util/set_kthread_prio we see: } else if (cmd ~ /^IRQ_/ && "IRQ_default" in config) { prio = config["IRQ_default"]; opts = confopts["IRQ_default"]; Note that the SR3-iFix1 kernel uses IRQ- and the SR3-iFix1 set_kthread_prio script uses IRQ_. From this, I can't imagine how SR3 ever had real-time priority hardware interrupt stubs. This is truly incredible given the lack of failures we've seen during testing. ------- Comment From dvhltc.com 2008-02-25 20:48 EDT-------
To confirm I didn't botch the code review and that the ABAT deploy wasn't
somehow at fault, I did an abat deploy of rhel5.1 on elm3b102 and then installed
SR3-iFix1 manually.
[root@elm3b102 ~]# uname -r
2.6.21.4-ibmrt1.23
[root@elm3b102 ~]# ps aux | grep IRQ
root 166 0.0 0.0 0 0 ? S< 20:41 0:00 [IRQ-9]
root 507 0.0 0.0 0 0 ? S< 20:41 0:00 [IRQ-8]
...
[root@elm3b102 ~]# ps -eLo rtprio,comm | grep IRQ
- IRQ-9
- IRQ-8
- IRQ-12
...
Applying the following patch:
39c39
< } else if (cmd ~ /^IRQ_/ &&
---
> } else if (cmd ~ /^IRQ[_-]/ &&
Rerunning the script we have:
# ps -eLo rtprio,comm | grep IRQ
95 IRQ-9
95 IRQ-8
...
This fix allows for both the old and new versions of the IRQ naming convention
to work. I would like to understand WHY this doesn't affect our testing more.
But I think we will have to send an update to the customer immediately, perhaps
not as an iFix, perhaps just the 1 line patch above with instructions for how to
run it (maybe even a script that fixes the problem with a sed command).
Thoughts on delivery?
Bumping priority to P1, we need to understand why this isn't showing up as a
bigger problem and how we'll get the fix out to customers.
------- Comment From jstultz.com 2008-02-26 18:15 EDT------- This is an IBM issue, and doesn't affect MRG or RH. I'm reject it. closing on our side. |