[PATCH] Fix declaration of cgroup_mm_owner_callbacks

[PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Paul Menage]

Fix declaration of cgroup_mm_owner_callbacks()

The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
shouldn't be based on CONFIG_MM_OWNER, but on
CONFIG_CGROUPS. Otherwise kernel/exit.c fails to compile when
something other than a cgroups controller selects CONFIG_MM_OWNER

Signed-off-by: Paul Menage <menage@google.com>

---

This is a retry with a mailer that hopefully didn't break the
whitespace formatting

 include/linux/cgroup.h |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

Index: mmowner-mmotm-2008-09-10/include/linux/cgroup.h
===================================================================
--- mmowner-mmotm-2008-09-10.orig/include/linux/cgroup.h
+++ mmowner-mmotm-2008-09-10/include/linux/cgroup.h
@@ -403,6 +403,9 @@ void cgroup_iter_end(struct cgroup *cgrp
 int cgroup_scan_tasks(struct cgroup_scanner *scan);
 int cgroup_attach_task(struct cgroup *, struct task_struct *);
 
+void cgroup_mm_owner_callbacks(struct task_struct *old,
+			       struct task_struct *new);
+
 #else /* !CONFIG_CGROUPS */
 
 static inline int cgroup_init_early(void) { return 0; }
@@ -421,15 +424,9 @@ static inline int cgroupstats_build(stru
 	return -EINVAL;
 }
 
+static inline void cgroup_mm_owner_callbacks(struct task_struct *old,
+					     struct task_struct *new) {}
+
 #endif /* !CONFIG_CGROUPS */
 
-#ifdef CONFIG_MM_OWNER
-extern void
-cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new);
-#else /* !CONFIG_MM_OWNER */
-static inline void
-cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
-{
-}
-#endif /* CONFIG_MM_OWNER */
 #endif /* _LINUX_CGROUP_H */

Re: [PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Pekka Enberg]

Paul Menage wrote:
> Fix declaration of cgroup_mm_owner_callbacks()
> 
> The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
> shouldn't be based on CONFIG_MM_OWNER, but on
> CONFIG_CGROUPS. Otherwise kernel/exit.c fails to compile when
> something other than a cgroups controller selects CONFIG_MM_OWNER
> 
> Signed-off-by: Paul Menage <menage@google.com>
> 
> ---
> 
> This is a retry with a mailer that hopefully didn't break the
> whitespace formatting

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

Re: [PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Pekka Enberg]

Andrew Morton wrote:
> On Mon, 15 Sep 2008 12:06:38 -0700 (PDT)
> menage@google.com (Paul Menage) wrote:
> 
>> Fix declaration of cgroup_mm_owner_callbacks()
>>
>> The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
>> shouldn't be based on CONFIG_MM_OWNER, but on
>> CONFIG_CGROUPS. Otherwise kernel/exit.c fails to compile when
>> something other than a cgroups controller selects CONFIG_MM_OWNER
>>
> 
> Being too lazy to go back and find out what "something" is, I assumed
> that this isn't needed in 2.6.27.

Something being the revokeat() patches I recently resurrected. So no, 
not for 2.6.27. :-)

Re: [PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Andrew Morton]

On Mon, 15 Sep 2008 12:06:38 -0700 (PDT)
menage@google.com (Paul Menage) wrote:

> Fix declaration of cgroup_mm_owner_callbacks()
> 
> The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
> shouldn't be based on CONFIG_MM_OWNER, but on
> CONFIG_CGROUPS. Otherwise kernel/exit.c fails to compile when
> something other than a cgroups controller selects CONFIG_MM_OWNER
> 

Being too lazy to go back and find out what "something" is, I assumed
that this isn't needed in 2.6.27.

Re: [PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Balbir Singh]

Andrew Morton wrote:
> On Mon, 15 Sep 2008 12:06:38 -0700 (PDT)
> menage@google.com (Paul Menage) wrote:
> 
>> Fix declaration of cgroup_mm_owner_callbacks()
>>
>> The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
>> shouldn't be based on CONFIG_MM_OWNER, but on
>> CONFIG_CGROUPS. Otherwise kernel/exit.c fails to compile when
>> something other than a cgroups controller selects CONFIG_MM_OWNER
>>
> 
> Being too lazy to go back and find out what "something" is, I assumed
> that this isn't needed in 2.6.27.

We don't have anything using CONFIG_MM_OWNER in 2.6.27, so we should be OK
pushing this to 2.6.28 (Pekka plans to use it for revoke* calls).

Pekka, Paul do you agree?


-- 
	Balbir

Re: [PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Pekka Enberg]

Balbir Singh wrote:
> Andrew Morton wrote:
>> On Mon, 15 Sep 2008 12:06:38 -0700 (PDT)
>> menage@google.com (Paul Menage) wrote:
>>
>>> Fix declaration of cgroup_mm_owner_callbacks()
>>>
>>> The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
>>> shouldn't be based on CONFIG_MM_OWNER, but on
>>> CONFIG_CGROUPS. Otherwise kernel/exit.c fails to compile when
>>> something other than a cgroups controller selects CONFIG_MM_OWNER
>>>
>> Being too lazy to go back and find out what "something" is, I assumed
>> that this isn't needed in 2.6.27.
> 
> We don't have anything using CONFIG_MM_OWNER in 2.6.27, so we should be OK
> pushing this to 2.6.28 (Pekka plans to use it for revoke* calls).

Oh, I am already using it:

http://git.kernel.org/?p=linux/kernel/git/penberg/linux-2.6.git;a=commitdiff;h=3201a05704afafd7c61b204b7f0c2a9ddcf935d0

Still debugging some ext3 corruption problems, though :-)

> Pekka, Paul do you agree?

Yes, agreed.

Re: [PATCH] Fix declaration of cgroup_mm_owner_callbacks

[Paul Menage]

On Wed, Sep 17, 2008 at 2:30 PM, Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>>
>> Being too lazy to go back and find out what "something" is, I assumed
>> that this isn't needed in 2.6.27.
>
> We don't have anything using CONFIG_MM_OWNER in 2.6.27, so we should be OK
> pushing this to 2.6.28 (Pekka plans to use it for revoke* calls).
>
> Pekka, Paul do you agree?
>

Yes, there's no rush for this.

Paul