sched: Simplify sys_sched_rr_get_interval() system call

By removing the need for it to know details of scheduling classes.

This allows PlugSched to define orthogonal scheduling classes.

Signed-off-by: Peter Williams <pwil3058@bigpond.net.au>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <06d1b89ee15a0eef82d7.1253496713@mudlark.pw.nest>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 16 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 1b900fb1c6e1..830967e18285 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6819,23 +6819,8 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
         if (retval)
                 goto out_unlock;
 
-        /*
-         * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
-         * tasks that are on an otherwise idle runqueue:
-         */
-        time_slice = 0;
-        if (p->policy == SCHED_RR) {
-                time_slice = DEF_TIMESLICE;
-        } else if (p->policy != SCHED_FIFO) {
-                struct sched_entity *se = &p->se;
-                unsigned long flags;
-                struct rq *rq;
+        time_slice = p->sched_class->get_rr_interval(p);
 
-                rq = task_rq_lock(p, &flags);
-                if (rq->cfs.load.weight)
-                        time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
-                task_rq_unlock(rq, &flags);
-        }
         read_unlock(&tasklist_lock);
         jiffies_to_timespec(time_slice, &t);
         retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;