Messages in this thread | | | Date | Tue, 3 Feb 2009 10:25:56 +0530 | From | Balbir Singh <> | Subject | Re: [-mm patch] Show memcg information during OOM |
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* David Rientjes <rientjes@google.com> [2009-02-02 20:47:05]:
> On Tue, 3 Feb 2009, Balbir Singh 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); > > > > > > I think this can be put outside the task lock. The lock is used to call task_cs() safely in > > > cpuset_print_task_mems_allowed(). > > > > > > > Thanks, I'll work on that in the next version. > > > > I was also wondering about this and assumed that it was necessary to > prevent the cgroup from disappearing during the oom. If task_lock() isn't > held, is the memcg->css.cgroup->dentry->d_name.name dereference always > safe without rcu? >
oom_kill_process is called with tasklist_lock held (read-mode). That should suffice, no? The memcg cannot go away since it has other groups or tasks associated with it.
-- Balbir
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