Re: [-mm patch] Show memcg information during OOM

David Rientjes
2009-02-03T06:04:22Z

On Tue, 3 Feb 2009, Daisuke Nishimura wrote:

> > > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> > > > index d3b9bac..b8e53ae 100644
> > > > --- a/mm/oom_kill.c
> > > > +++ b/mm/oom_kill.c
> > > > @@ -392,6 +392,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> > > > current->comm, gfp_mask, order, current->oomkilladj);
> > > > task_lock(current);
> > > > cpuset_print_task_mems_allowed(current);
> > > > + mem_cgroup_print_mem_info(mem);
> > >
> > > mem is only !NULL when we come from mem_cgroup_out_of_memory(). This
> > > crashes otherwise in mem_cgroup_print_mem_info(), no?
> > >
> > I think you're right.
> >
> > IMHO, "mem_cgroup_print_mem_info(current)" would be better here,
> > and call mem_cgroup_from_task at mem_cgroup_print_mem_info.
> >
> Reading other messages on this thread, mem_cgroup_print_mem_info
> should be called only when oom_kill_process is called from mem_cgroup_out_of_memory,
> so checking "if (!mem)" would be enough.
>

You're right, but it's understandable why there would be confusion since
it's very poorly documented.