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[PATCH] sched/fair: fix incorrect calculation of capacity in scale_rt_capacity

From Chao Yu <chao2.yu@samsung.com>
Newsgroups linux.kernel
Subject [PATCH] sched/fair: fix incorrect calculation of capacity in scale_rt_capacity
Date 2015-09-23 08:20 +0200
Message-ID <qbLzj-4fg-5@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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div_u64 can only handle 32-bits divisor, if our divisor is with type of
64-bits, we should use div64_u64 instead, otherwise value of divisor will
be cast to 32-bits, resulting in wrong calculation.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9176f7c..ee268ef 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6086,7 +6086,7 @@ static unsigned long scale_rt_capacity(int cpu)
 
 	total = sched_avg_period() + delta;
 
-	used = div_u64(avg, total);
+	used = div64_u64(avg, total);
 
 	if (likely(used < SCHED_CAPACITY_SCALE))
 		return SCHED_CAPACITY_SCALE - used;
-- 
2.5.2


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[PATCH] sched/fair: fix incorrect calculation of capacity in  scale_rt_capacity Chao Yu <chao2.yu@samsung.com> - 2015-09-23 08:20 +0200
  Re: [PATCH] sched/fair: fix incorrect calculation of capacity in  scale_rt_capacity Peter Zijlstra <peterz@infradead.org> - 2015-09-30 18:30 +0200

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