[Devel] Re: [PATCH v2 3/5] change number_of_cpusets to an atomic

[Christoph Lameter]

On Mon, 23 Apr 2012, Glauber Costa wrote:

> This will allow us to call destroy() without holding the
> cgroup_mutex(). Other important updates inside update_flags()
> are protected by the callback_mutex.
>
> We could protect this variable with the callback_mutex as well,
> as suggested by Li Zefan, but we need to make sure we are protected
> by that mutex at all times, and some of its updates happen inside the
> cgroup_mutex - which means we would deadlock.

Would this not also be a good case to introduce static branching?

number_of_cpusets is used to avoid going through unnecessary processing
should there be no cpusets in use.