Re: [patch 3/3] sched: move sched_avg_update() to update_cpu_load()

[Suresh Siddha <suresh.b.siddha@intel.com>]

On Fri, 2010-08-20 at 06:47 -0700, Peter Zijlstra wrote:
> breaks CONFIG_SMP=n builds..
> 
>   CC      kernel/sched.o
> /usr/src/linux-2.6/kernel/sched.c: In function ‘update_cpu_load’:
> /usr/src/linux-2.6/kernel/sched.c:3186: error: implicit declaration of function ‘sched_avg_update’  CC      kernel/sched.o
> /usr/src/linux-2.6/kernel/sched.c: In function ‘update_cpu_load’:
> /usr/src/linux-2.6/kernel/sched.c:3186: error: implicit declaration of function ‘sched_avg_update’

Updated patch appended. Thanks.
---

From: Suresh Siddha <suresh.b.siddha@intel.com>
Subject: sched: move sched_avg_update() to update_cpu_load()

Currently sched_avg_update() (which updates rt_avg stats in the rq) is getting
called from scale_rt_power() (in the load balance context) which doesn't take
rq->lock.

Fix it by moving the sched_avg_update() to more appropriate update_cpu_load()
where the CFS load gets updated aswell.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
---
 kernel/sched.c      |    6 ++++++
 kernel/sched_fair.c |    2 --
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 41541d7..f95bbbe 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1294,6 +1294,10 @@ static void resched_task(struct task_struct *p)
 static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
 {
 }
+
+static void sched_avg_update(struct rq *rq)
+{
+}
 #endif /* CONFIG_SMP */
 
 #if BITS_PER_LONG == 32
@@ -3182,6 +3186,8 @@ static void update_cpu_load(struct rq *this_rq)
 
 		this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
 	}
+
+	sched_avg_update(this_rq);
 }
 
 static void update_cpu_load_active(struct rq *this_rq)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 806d1b2..a2bf7bd 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -2268,8 +2268,6 @@ unsigned long scale_rt_power(int cpu)
 	struct rq *rq = cpu_rq(cpu);
 	u64 total, available;
 
-	sched_avg_update(rq);
-
 	total = sched_avg_period() + (rq->clock - rq->age_stamp);
 	available = total - rq->rt_avg;