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SubjectRe: [cgroup/task_lock] INFO: suspicious RCU usage.
Hello, Li.

On Tue, Feb 25, 2014 at 08:01:25PM +0800, Li Zefan wrote:
...
> >> So, this is from removing task_lock from task_css_set_check() and
> >> adding rcu_read_lock() in cpuset_cpus_allowed() should fix it.
> >
> > Yeah, rcu_read_lock() should be sufficient.
> >
> >> I'm
> >> not sure how much of task_lock() locking we currently have in cpuset
> >> is actually necessary tho. Shouldn't we be able to do most with just
> >> callback_mutex, if not cpuset_mutex? Li, any ideas?
> >>
> >
> > task_lock() is also used to protect task->mems_allowed. I'll see if we
> > can get rid of most (if not all) task_lock() lockings in cpuset.
> >
>
> After a quick lock, I think except the one in cpuset_change_task_nodemask(), all
> other task_lock() lockings can be replace by rcu_readlock().

I committed the original series as-is. Can you please post follow-up
patches to update cpuset locking?

Thanks.

--
tejun


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