repost - RFC [Patch] Remove "please try 'cgroup_disable=memory' option if you don't want memory cgroups" printk at boot time.

repost - RFC [Patch] Remove "please try 'cgroup_disable=memory' option if you don't want memory cgroups" printk at boot time.

[Larry Woodman]

[-- Attachment #1: Type: text/plain, Size: 322 bytes --]

Re-posting, cc'ing linux-mm as requested:

We are considering removing this printk at boot time from RHEL because
it will confuse customers, encourage them to change the boot parameters
and generate extraneous support calls.  Its documented in
Documentation/kernel-parameters.txt anyway.  Any thoughts???

Larry Woodman



[-- Attachment #2: rhel6-cgroup.patch --]
[-- Type: text/x-patch, Size: 459 bytes --]

diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 3d535d5..2029fae 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -83,8 +83,6 @@ void __init page_cgroup_init_flatmem(void)
 			goto fail;
 	}
 	printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
-	printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
-	" don't want memory cgroups\n");
 	return;
 fail:
 	printk(KERN_CRIT "allocation of page_cgroup failed.\n");

Re: repost - RFC [Patch] Remove "please try 'cgroup_disable=memory' option if you don't want memory cgroups" printk at boot time.

[KAMEZAWA Hiroyuki]

On Tue, 20 Apr 2010 10:26:27 -0400
Larry Woodman <lwoodman@redhat.com> wrote:

> Re-posting, cc'ing linux-mm as requested:
> 
> We are considering removing this printk at boot time from RHEL because
> it will confuse customers, encourage them to change the boot parameters
> and generate extraneous support calls.  Its documented in
> Documentation/kernel-parameters.txt anyway.  Any thoughts???
> 
> Larry Woodman
> 
For RHEL, I agree removing the message makes sense.
But I'm unsure that small machine users, who never use memcg, can notice some
amount of memory are eaten at boot time.

Many distro tends to enable memcg by default and consume memory.

 	printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
-	printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
-	" don't want memory cgroups\n");

Hmm.

	printk(KERN_INFO "If you don't want page_cgroup,
			  you can disable this by boot option, cgroup_disable=memory".)

My biggest concern is that we don't have man(5) cgroup as other file systems.
If we have man(5), the best place for this kind of information will be it.
I think most of users will never see kernel-parameter.txt ..

If usual distros are shipped with man(5) cgroup, I agree removing
this in upstream.
(We have man pages for libcgroup but not man(5) for cgroup file system.)

I'm sorry if I don't notice that the latest man package has cgroup section.

Bye,
-Kame

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Re: repost - RFC [Patch] Remove "please try 'cgroup_disable=memory' option if you don't want memory cgroups" printk at boot time.

[Li Zefan]

> My biggest concern is that we don't have man(5) cgroup as other file systems.
> If we have man(5), the best place for this kind of information will be it.
> I think most of users will never see kernel-parameter.txt ..
> 
> If usual distros are shipped with man(5) cgroup, I agree removing
> this in upstream.
> (We have man pages for libcgroup but not man(5) for cgroup file system.)
> 
> I'm sorry if I don't notice that the latest man package has cgroup section.
> 

We have a man-page for cpuset, which was written by Paul Jackson,
the author of cpuset.

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Re: repost - RFC [Patch] Remove "please try 'cgroup_disable=memory' option if you don't want memory cgroups" printk at boot time.

[KAMEZAWA Hiroyuki]

On Wed, 21 Apr 2010 08:56:20 +0800
Li Zefan <lizf@cn.fujitsu.com> wrote:

> > My biggest concern is that we don't have man(5) cgroup as other file systems.
> > If we have man(5), the best place for this kind of information will be it.
> > I think most of users will never see kernel-parameter.txt ..
> > 
> > If usual distros are shipped with man(5) cgroup, I agree removing
> > this in upstream.
> > (We have man pages for libcgroup but not man(5) for cgroup file system.)
> > 
> > I'm sorry if I don't notice that the latest man package has cgroup section.
> > 
> 
> We have a man-page for cpuset, which was written by Paul Jackson,
> the author of cpuset.
> 
But there is no description about "cpuset can be mounted as cgroup".

Maybe there are no updates for 2 years even if it exists.

Thanks,
-Kame

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