Bug 1318646

Summary:	[RFE] Show actual running udev max-childs parameter
Product:	Red Hat Enterprise Linux 6	Reporter:	Stefan Meyer <smeyer>
Component:	udev	Assignee:	Michal Sekletar <msekleta>
Status:	CLOSED WONTFIX	QA Contact:	qe-baseos-daemons
Severity:	high	Docs Contact:
Priority:	high
Version:	6.9	CC:	dmoessne, smeyer, udev-maint-list
Target Milestone:	rc	Keywords:	FutureFeature
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:
Clones:	1361601 (view as bug list)		Environment:	All RHEL versions
Last Closed:	2016-07-29 13:32:21 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:
Bug Depends On:
Bug Blocks:	1269194, 1356047

Description Stefan Meyer 2016-03-17 12:39:12 UTC

Description of problem:
When overriding the parameters for 

RHEL 5: udevcontrol max_childs=X
RHEL 6: udevadm control --max-childs=X
RHEL 7: udevadm control --children-max=X

either on the command line or via kernel boot parameters there is no way 
to show the currently configured value once the system is fully booted.

Version-Release number of selected component (if applicable):
RHEL 5, 6 and 7

How reproducible:
Always

Steps to Reproduce:
RHEL 5: # udevcontrol max_childs=7
RHEL 6: # udevadm control --max-childs=7
RHEL 7: # udevadm control --children-max=7

There is no way to read the currently set value.


Actual results:
No command option available to show the actual used value.

Expected results:
Create a command option for udevcontrol/udevadm to show the running configuration.

As an alternative:
Make the information available in /proc/<process_id>

As the preferred option:
Make the actual configured udev timeout parameter visible.

Additional info:

Comment 3 Michal Sekletar 2016-07-22 07:20:40 UTC

udevadm and udevd interaction is only one directional, meaning that udevadm only sends control command to udev daemon, but no data is returned back from the daemon to client.

For now I've implemented change that introduces new option for udevadm control and udevd upon receiving new type of control message logs current value of children_max parameter on INFO log level, hence message is by default visible in system log. 

Would above solution satisfy this RFE?

Comment 4 Stefan Meyer 2016-07-22 07:35:58 UTC

That solution would not satisfy the RFE as logs are purged automatically and the control messages with it.

Comment 5 Michal Sekletar 2016-07-29 13:29:08 UTC

(In reply to Stefan Meyer from comment #4)
> That solution would not satisfy the RFE as logs are purged automatically and
> the control messages with it.

I've reworked my initial implementation and proposed it upstream, but PR was rejected. However, we will address this issue upstream, but approach will be very different from my solution. Unfortunately, it won't be possible to backport new fix to RHEL6. I will clone this bug for RHEL7 and close this one.

https://github.com/systemd/systemd/pull/3808