From ede3d0fba99520f268067917b50858d788bc41da Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Tue, 8 Nov 2005 21:39:00 -0800
Subject: [PATCH] [PATCH] sched: consider migration thread with smp nice
The intermittent scheduling of the migration thread at ultra high priority
makes the smp nice handling see that runqueue as being heavily loaded. The
migration thread itself actually handles the balancing so its influence on
priority balancing should be ignored.
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/sched.c | 35 ++++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 9 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 502d47c883b6a..0f2def822296c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -670,6 +670,31 @@ static inline void dec_prio_bias(runqueue_t *rq, int prio)
{
rq->prio_bias -= MAX_PRIO - prio;
}
+
+static inline void inc_nr_running(task_t *p, runqueue_t *rq)
+{
+ rq->nr_running++;
+ if (rt_task(p)) {
+ if (p != rq->migration_thread)
+ /*
+ * The migration thread does the actual balancing. Do
+ * not bias by its priority as the ultra high priority
+ * will skew balancing adversely.
+ */
+ inc_prio_bias(rq, p->prio);
+ } else
+ inc_prio_bias(rq, p->static_prio);
+}
+
+static inline void dec_nr_running(task_t *p, runqueue_t *rq)
+{
+ rq->nr_running--;
+ if (rt_task(p)) {
+ if (p != rq->migration_thread)
+ dec_prio_bias(rq, p->prio);
+ } else
+ dec_prio_bias(rq, p->static_prio);
+}
#else
static inline void inc_prio_bias(runqueue_t *rq, int prio)
{
@@ -678,25 +703,17 @@ static inline void inc_prio_bias(runqueue_t *rq, int prio)
static inline void dec_prio_bias(runqueue_t *rq, int prio)
{
}
-#endif
static inline void inc_nr_running(task_t *p, runqueue_t *rq)
{
rq->nr_running++;
- if (rt_task(p))
- inc_prio_bias(rq, p->prio);
- else
- inc_prio_bias(rq, p->static_prio);
}
static inline void dec_nr_running(task_t *p, runqueue_t *rq)
{
rq->nr_running--;
- if (rt_task(p))
- dec_prio_bias(rq, p->prio);
- else
- dec_prio_bias(rq, p->static_prio);
}
+#endif
/*
* __activate_task - move a task to the runqueue.
--
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