Re: [PATCH next-20130703] net: sock: Add ifdef CONFIG_MEMCG_KMEM for mem_cgroup_sockets_{init,destroy}

Michal Hocko
2013-07-03T16:00:03Z

On Wed 03-07-13 17:53:21, Sedat Dilek wrote:
> On Wed, Jul 3, 2013 at 5:20 PM, Michal Hocko <mhocko@suse.cz> wrote:
> > On Wed 03-07-13 20:51:00, Li Zefan wrote:
> > [...]
> >> [PATCH] memcg: fix build error if CONFIG_MEMCG_KMEM=n
> >>
> >> Fix this build error:
> >>
> >> mm/built-in.o: In function `mem_cgroup_css_free':
> >> memcontrol.c:(.text+0x5caa6): undefined reference to
> >> 'mem_cgroup_sockets_destroy'
> >>
> >> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> >> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> >> Signed-off-by: Li Zefan <lizefan@huawei.com>
> >
> > I am seeing the same thing I just didn't get to reporting it.
> > The other approach is not bad as well but I find this tiny better
> > because mem_cgroup_css_free should care only about a single cleanup
> > function for whole kmem. If that one needs to do tcp kmem specific
> > cleanup then it should be done inside kmem_cgroup_css_offline.
> >
>
> As said in my other mail, for me this makes sense as it is a followup.
>
> But, still I don't know why sock.c has is own mem_cgroup_sockets_{init,destroy}.

That is the only definition AFAICS (except for !CONFIG_NET where it
expands to NOOP). Please note that memcg_init_kmem is a common kmem
initializator and it needs to be prepared for !CONFIG_NET.

The same applies to _destroy.
Makes more sense now?

[...]
--
Michal Hocko
SUSE Labs