sched: Introduce task_times() to replace task_{u,s}time() pair

sched: Introduce task_times() to replace task_{u,s}time() pair

Functions task_{u,s}time() are called in pair in almost all
cases.  However task_stime() is implemented to call task_utime()
from its inside, so such paired calls run task_utime() twice.

It means we do heavy divisions (div_u64 + do_div) twice to get
utime and stime which can be obtained at same time by one set
of divisions.

This patch introduces a function task_times(*tsk, *utime,
*stime) to retrieve utime and stime at once in better, optimized
way.

Signed-off-by: Hidetoshi Seto <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Spencer Candland <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Americo Wang <[email protected]>
LKML-Reference: <4B0E16AE[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>