Kernel panic - not syncing: No init found; after lots of scheduling
while atomics, starting from when async_thread does sd_probe_async.

mem_cgroup_soft_limit_check() was doing an unbalanced get_cpu(): don't
get_cpu if we won't need it, and put_cpu if we did get_cpu.

And fix the silliness of passing it an "over_soft_limit" argument
that just tells it to return false when false.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>