Re: [patch 00/18] CFS Bandwidth Control v7.2

Paul Turner
2011-07-28T02:59:55Z

On Mon, Jul 25, 2011 at 8:00 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, 2011-07-25 at 16:58 +0200, Peter Zijlstra wrote:
>> +               rcu_read_lock();
>> +               ret = walk_tg_tree_from(tg, tg_set_cfs_period_down, NULL, &period);
>> +               rcu_read_unlock();
>
> rcu over a mutex doesn't really work in mainline, bah..
>

Isn't this the other way around though? We already hold the mutex so
we shouldn't be blocking within the RCU section.

rcu_lock here is only to stop nodes in the tree from disappearing
under us on the walk.

(FWIW this is the same as the rt_schedulable case)