Changes css_set freeing mechanism to be under RCU
This is a prepatch for making the procs file writable. In order to free the
old css_sets for each task to be moved as they're being moved, the freeing
mechanism must be RCU-protected, or else we would have to have a call to
synchronize_rcu() for each task before freeing its old css_set.
Signed-off-by: Ben Blum <[email protected]>
Signed-off-by: Paul Menage <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Acked-by: Li Zefan <[email protected]>
Cc: Matt Helsley <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>