Error with cgroups: "unused subsystem ns"

Error with cgroups: "unused subsystem ns"

[Sharyathi Nagesh]

Hi

Description:
   We have noticed kernel error message on the dmesg when ltp test cases 
are executed. We observed multiple instance of error message:
                   "Not cloning cgroup for unused subsystem ns" in dmesg

Test:
The messages were seen when ltp test case for the containers are executed:
ltp -f containers

Solution:
Alexey Dobriyan had provided a patch to address the issue. Where the 
printk was removed. The patch still haven't made it to main line and 
hence we still see the messages.
The patch can be found here:
  http://git.openvz.org/?p=linux-2.6.24-openvz;a=log;h=v2.6.24-ovz002.2

Would this be the right way to handle the issue?
if so
When can we expect this to be included into mainline
Thanks
Yeehaw

Re: Error with cgroups: "unused subsystem ns"

[Serge E. Hallyn]

Quoting Sharyathi Nagesh (sharyath@in.ibm.com):
> Hi
>
> Description:
>   We have noticed kernel error message on the dmesg when ltp test cases are 
> executed. We observed multiple instance of error message:
>                   "Not cloning cgroup for unused subsystem ns" in dmesg
>
> Test:
> The messages were seen when ltp test case for the containers are executed:
> ltp -f containers
>
> Solution:
> Alexey Dobriyan had provided a patch to address the issue. Where the printk 
> was removed. The patch still haven't made it to main line and hence we 
> still see the messages.
> The patch can be found here:
>  http://git.openvz.org/?p=linux-2.6.24-openvz;a=log;h=v2.6.24-ovz002.2
>
> Would this be the right way to handle the issue?
> if so
> When can we expect this to be included into mainline

Resend the patch to lkml.  Assuming you are talking about commit id
93af30a60055a83a00188ae04b88bbd9b4e1489a, go ahead and add my
Acked-by.

Converting it to a pr_debug() might be another thing to consider, but
I'm not sure anyone wants these messages.

-serge

Re: Error with cgroups: "unused subsystem ns"

[Sharyathi Nagesh]

[-- Attachment #1: Type: text/plain, Size: 421 bytes --]

Serge
> 
> Resend the patch to lkml.  Assuming you are talking about commit id
> 93af30a60055a83a00188ae04b88bbd9b4e1489a, go ahead and add my
> Acked-by.
Yes it is the same patch. I am attaching the patch for 2.6.28-rc8 let me 
know: when this can accepted into main line?

> Converting it to a pr_debug() might be another thing to consider, but
> I'm not sure anyone wants these messages.
> 
> -serge

Thanks
Yeehaw




[-- Attachment #2: unused_subsystem_ns.patch --]
[-- Type: text/x-diff, Size: 666 bytes --]

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Sharyathi Nagesh <sharyathi@in.ibm.com>

Acked-by: Serge E. Hallyn <serge@hallyn.com>
-----------------


Index: linux-2.6.28-rc8/kernel/cgroup.c
===================================================================
--- linux-2.6.28-rc8.orig/kernel/cgroup.c	2008-12-11 04:41:51.000000000 +0530
+++ linux-2.6.28-rc8/kernel/cgroup.c	2008-12-18 21:55:58.000000000 +0530
@@ -2934,9 +2934,6 @@
  again:
 	root = subsys->root;
 	if (root == &rootnode) {
-		printk(KERN_INFO
-		       "Not cloning cgroup for unused subsystem %s\n",
-		       subsys->name);
 		mutex_unlock(&cgroup_mutex);
 		return 0;
 	}

Re: Error with cgroups: "unused subsystem ns"

[Andrew Morton]

On Thu, 18 Dec 2008 16:45:38 +0530
Sharyathi Nagesh <sharyath@in.ibm.com> wrote:

> Serge
> > 
> > Resend the patch to lkml.  Assuming you are talking about commit id
> > 93af30a60055a83a00188ae04b88bbd9b4e1489a, go ahead and add my
> > Acked-by.
> Yes it is the same patch. I am attaching the patch for 2.6.28-rc8 let me 
> know: when this can accepted into main line?
> 
> > Converting it to a pr_debug() might be another thing to consider, but
> > I'm not sure anyone wants these messages.
> > 
> > -serge
> 
> Thanks
> Yeehaw
> 
> 
> 
> 
> 
> [unused_subsystem_ns.patch  text/x-diff (667B)]
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> Signed-off-by: Sharyathi Nagesh <sharyathi@in.ibm.com>
> 
> Acked-by: Serge E. Hallyn <serge@hallyn.com>
> -----------------
> 
> 
> Index: linux-2.6.28-rc8/kernel/cgroup.c
> ===================================================================
> --- linux-2.6.28-rc8.orig/kernel/cgroup.c	2008-12-11 04:41:51.000000000 +0530
> +++ linux-2.6.28-rc8/kernel/cgroup.c	2008-12-18 21:55:58.000000000 +0530
> @@ -2934,9 +2934,6 @@
>   again:
>  	root = subsys->root;
>  	if (root == &rootnode) {
> -		printk(KERN_INFO
> -		       "Not cloning cgroup for unused subsystem %s\n",
> -		       subsys->name);
>  		mutex_unlock(&cgroup_mutex);
>  		return 0;
>  	}
> 

I'm unsure waht to make of this.  It has no changelog.  It appears to have
been authored by yourself, although it's unclear why it has Alexey's
signoff as well.

Re: Error with cgroups: "unused subsystem ns"

[Sharyathi Nagesh]

[-- Attachment #1: Type: text/plain, Size: 295 bytes --]

Andrew Morton wrote:
> 
> I'm unsure waht to make of this.  It has no changelog.  It appears to have
> been authored by yourself, although it's unclear why it has Alexey's
> signoff as well.

This patch is originally from Alexy I have just ported it into latest 
kernel mainline
Thanks
Yeehaw



[-- Attachment #2: unused_subsystem_ns.patch --]
[-- Type: text/x-diff, Size: 790 bytes --]

This patch removes spurious warning messages that are thrown into 
the console during cgroup operations. 

-----------------
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Sharyathi Nagesh <sharyathi@in.ibm.com>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
-----------------


Index: linux-2.6.28-rc8/kernel/cgroup.c
===================================================================
--- linux-2.6.28-rc8.orig/kernel/cgroup.c	2008-12-11 04:41:51.000000000 +0530
+++ linux-2.6.28-rc8/kernel/cgroup.c	2008-12-18 21:55:58.000000000 +0530
@@ -2934,9 +2934,6 @@
  again:
 	root = subsys->root;
 	if (root == &rootnode) {
-		printk(KERN_INFO
-		       "Not cloning cgroup for unused subsystem %s\n",
-		       subsys->name);
 		mutex_unlock(&cgroup_mutex);
 		return 0;
 	}