linux-kernel - [PATCH 2/7] RT: Peter Zijlstra's suggested improvements to rt-push patch

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Date:	Thu, 11 Oct 2007 17:59:53 -0400
From:	Gregory Haskins <ghaskins@...ell.com>
To:	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <peterz@...radead.org>
Cc:	linux-rt-users <linux-rt-users@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Gregory Haskins <ghaskins@...ell.com>
Subject: [PATCH 2/7] RT: Peter Zijlstra's suggested improvements to rt-push
	patch

This is my own interpretation of Peter's recommended changes Steven's push-rt
patch.  Just to be clear, Peter does not endorse this patch unless he himself
specifically says so ;).

Signed-off-by: Gregory Haskins <ghaskins@...ell.com>
---

 kernel/sched.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 0f0af6d..24b38b4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1499,7 +1499,7 @@ static int push_rt_task(struct rq *this_rq)
 	int dst_cpu = -1;
 	int ret = 0;
 
-	BUG_ON(!spin_is_locked(&this_rq->lock));
+	assert_spin_locked(&this_rq->lock);
 
 	next_task = rt_next_highest_task(this_rq);
 	if (!next_task)
@@ -1553,7 +1553,8 @@ static int push_rt_task(struct rq *this_rq)
 		set_task_cpu(next_task, dst_cpu);
 		activate_task(lowest_rq, next_task, 0);
 
-		set_tsk_need_resched(lowest_rq->curr);
+		resched_task(lowest_rq->curr);
+		schedstat_inc(this_rq, rto_schedule);
 
 		spin_unlock(&lowest_rq->lock);
 		ret = 1;
@@ -2290,10 +2291,9 @@ static inline void finish_task_switch(struct rq *rq, struct task_struct *prev)
 	 * then kick other CPUs, they might run it:
 	 */
 	rq->curr_prio = current->prio;
-	if (unlikely(rt_task(current) && push_rt_task(rq))) {
-		schedstat_inc(rq, rto_schedule);
-		smp_send_reschedule_allbutself_cpumask(current->cpus_allowed);
-	}
+	if (unlikely(rq->rt_nr_running > 1))
+		push_rt_task(rq);
+
 #endif
 	prev_state = prev->state;
 	_finish_arch_switch(prev);

-
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