Re: [PATCH v2 3/9] socket: initial cgroup code.

From: Kirill A. Shutemov
Date: Thu Sep 08 2011 - 01:36:04 EST


On Thu, Sep 08, 2011 at 01:54:03AM -0300, Glauber Costa wrote:
> On 09/07/2011 07:17 PM, Kirill A. Shutemov wrote:
> > On Wed, Sep 07, 2011 at 01:23:13AM -0300, Glauber Costa wrote:
> >> We aim to control the amount of kernel memory pinned at any
> >> time by tcp sockets. To lay the foundations for this work,
> >> this patch adds a pointer to the kmem_cgroup to the socket
> >> structure.
> >>
> >> Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
> >> CC: David S. Miller<davem@xxxxxxxxxxxxx>
> >> CC: Hiroyouki Kamezawa<kamezawa.hiroyu@xxxxxxxxxxxxxx>
> >> CC: Eric W. Biederman<ebiederm@xxxxxxxxxxxx>
> >> ---
> >> include/linux/kmem_cgroup.h | 29 +++++++++++++++++++++++++++++
> >> include/net/sock.h | 2 ++
> >> net/core/sock.c | 5 ++---
> >> 3 files changed, 33 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/include/linux/kmem_cgroup.h b/include/linux/kmem_cgroup.h
> >> index 0e4a74b..77076d8 100644
> >> --- a/include/linux/kmem_cgroup.h
> >> +++ b/include/linux/kmem_cgroup.h
> >> @@ -49,5 +49,34 @@ static inline struct kmem_cgroup *kcg_from_task(struct task_struct *tsk)
> >> return NULL;
> >> }
> >> #endif /* CONFIG_CGROUP_KMEM */
> >> +
> >> +#ifdef CONFIG_INET
> >
> > Will it break something if you define the helpers even if CONFIG_INET
> > is not defined?
> > It will be much cleaner. You can reuse ifdef CONFIG_CGROUP_KMEM in this
> > case.
>
> The helpers inside CONFIG_INET are needed for the network code,
> regardless of kmem cgroup is defined or not, not the other way around.
>
> So I could remove CONFIG_INET, but I can't possibly move it inside
> CONFIG_CGROUP_KMEM. So this buy us nothing.

You can define empty under CONFIG_CGROUP_KMEM's #else, can't you?
Like with kcg_from_cgroup()/kcg_from_task().

--
Kirill A. Shutemov
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