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| author | Gregory Haskins <ghaskins@novell.com> | 2008-01-25 21:08:09 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-25 21:08:09 +0100 |
| commit | e7693a362ec84bb5b6fd441d8a8b4b9d568a7a0c (patch) | |
| tree | 078940540641a59aaf199695bfc6de3f062a987b /kernel/sched_idletask.c | |
| parent | 697f0a487f294e634a342764472b79375bb3158a (diff) | |
| download | lwn-e7693a362ec84bb5b6fd441d8a8b4b9d568a7a0c.tar.gz lwn-e7693a362ec84bb5b6fd441d8a8b4b9d568a7a0c.zip | |
sched: de-SCHED_OTHER-ize the RT path
The current wake-up code path tries to determine if it can optimize the
wake-up to "this_cpu" by computing load calculations. The problem is that
these calculations are only relevant to SCHED_OTHER tasks where load is king.
For RT tasks, priority is king. So the load calculation is completely wasted
bandwidth.
Therefore, we create a new sched_class interface to help with
pre-wakeup routing decisions and move the load calculation as a function
of CFS task's class.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_idletask.c')
| -rw-r--r-- | kernel/sched_idletask.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c index bf9c25c15b8b..ca5374860aef 100644 --- a/kernel/sched_idletask.c +++ b/kernel/sched_idletask.c @@ -5,6 +5,12 @@ * handled in sched_fair.c) */ +#ifdef CONFIG_SMP +static int select_task_rq_idle(struct task_struct *p, int sync) +{ + return task_cpu(p); /* IDLE tasks as never migrated */ +} +#endif /* CONFIG_SMP */ /* * Idle tasks are unconditionally rescheduled: */ @@ -72,6 +78,9 @@ const struct sched_class idle_sched_class = { /* dequeue is not valid, we print a debug message there: */ .dequeue_task = dequeue_task_idle, +#ifdef CONFIG_SMP + .select_task_rq = select_task_rq_idle, +#endif /* CONFIG_SMP */ .check_preempt_curr = check_preempt_curr_idle, |