linux/debian/patches/features/all/rt/0129-sched-cond-resched.patch.patch

From 1aa975279d4a5596e082534477783a3961a32c62 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 7 Jun 2011 11:25:03 +0200
Subject: [129/256] sched-cond-resched.patch

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/sched/core.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7fd59a2..dbe9a7d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4554,9 +4554,17 @@ static inline int should_resched(void)
 
 static void __cond_resched(void)
 {
-	add_preempt_count(PREEMPT_ACTIVE);
-	__schedule();
-	sub_preempt_count(PREEMPT_ACTIVE);
+	do {
+		add_preempt_count(PREEMPT_ACTIVE);
+		__schedule();
+		sub_preempt_count(PREEMPT_ACTIVE);
+		/*
+		 * Check again in case we missed a preemption
+		 * opportunity between schedule and now.
+		 */
+		barrier();
+
+	} while (need_resched());
 }
 
 int __sched _cond_resched(void)