On Wed, 8 Feb 2017, Michal Hocko wrote: > > Huch? stop_machine() is horrible and heavy weight. Don't go there, there > > must be simpler solutions than that. > > Absolutely agreed. We are in the page allocator path so using the > stop_machine* is just ridiculous. And, in fact, there is a much simpler > solution [1]
That is nonsense. stop_machine would be used when adding removing a processor. There would be no need to synchronize when looping over active cpus anymore. get_online_cpus() etc would be removed from the hot path since the cpu masks are guaranteed to be stable.
