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Date: Tue, 24 May 2011 21:27:10 +0800
Message-ID: <BANLkTin4OiDiPO3znMvKTVZcYukHReydMQ@mail.gmail.com>
Subject: [PATCH] sched: fix need_resched() when checking peempt
From: Hillf Danton <dhillf@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
        Steven Rostedt <rostedt@goodmis.org>, Mike Galbraith <efault@gmx.de>,
        Yong Zhang <yong.zhang0@gmail.com>
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When checking if current task could be preempted by a newly woken task,
further check could be bypassed if the current thread is different from
the current task of run-queue, and it is corrected accordingly.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
---

--- tip-git/kernel/sched_rt.c	Sun May 22 20:12:01 2011
+++ sched_rt.c	Tue May 24 20:31:27 2011
@@ -1074,7 +1074,7 @@ static void check_preempt_curr_rt(struct
 	 * to move current somewhere else, making room for our non-migratable
 	 * task.
 	 */
-	if (p->prio == rq->curr->prio && !need_resched())
+	if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
 		check_preempt_equal_prio(rq, p);
 #endif
 }