>
> runnable_load_avg is u64, so you need to use div_u64() similar to how it
> is already done in task_h_load() further down in this patch. It doesn't
> build on ARM as is.
>
> Fix:
> - load /= tg->parent->cfs_rq[cpu]->runnable_load_avg + 1;
> + load = div_u64(load,
> tg->parent->cfs_rq[cpu]->runnable_load_avg + 1);
>
> Morten
Thank a lot for review!
div_u64 or do_div will do force cast u32 on the divisor, so in 64bit machine,
the divisor may become incorrect.
Since cfs_rq->runnable_load_avg is always smaller the cfs_rq.load.weight. and
load.weight is 'unsigned long', we can cast the runnable_load_avg to
'unsigned long' too. Than the div will fit on both 64/32 bit machine and no
data concatenate!
So the patch changed as following.
BTW, Paul & Peter:
in cfs_rq, runnable_load_avg, blocked_load_avg, tg_load_contrib are all
u64, but their are similar with 'unsigned long' load.weight. So could we change
them to 'unsigned long'?
---
>From 4a17564363f6d65c9d513ad206b54ebd032d3f46 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex....@intel.com>
Date: Mon, 3 Dec 2012 23:00:53 +0800
Subject: [PATCH 7/8] sched: consider runnable load average in move_tasks
Except using runnable load average in background, move_tasks is also
the key functions in load balance. We need consider the runnable load
average in it in order to the apple to apple load comparison.
Morten catch a div u64 bug on ARM, thanks!
Signed-off-by: Alex Shi <alex....@intel.com>
---
kernel/sched/fair.c | 17 ++++++++++-------
1 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index eadd2e7..73e4507 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4178,11 +4178,14 @@ static int tg_load_down(struct task_group *tg, void
*data)
long cpu = (long)data;
if (!tg->parent) {
- load = cpu_rq(cpu)->load.weight;
+ load = cpu_rq(cpu)->avg.load_avg_contrib;
} else {
+ unsigned long tmp_rla;
+ tmp_rla = tg->parent->cfs_rq[cpu]->runnable_load_avg + 1;
+
load = tg->parent->cfs_rq[cpu]->h_load;
- load *= tg->se[cpu]->load.weight;
- load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
+ load *= tg->se[cpu]->avg.load_avg_contrib;
+ load /= tmp_rla;
}
tg->cfs_rq[cpu]->h_load = load;
@@ -4208,12 +4211,12 @@ static void update_h_load(long cpu)
static unsigned long task_h_load(struct task_struct *p)
{
struct cfs_rq *cfs_rq = task_cfs_rq(p);
- unsigned long load;
+ unsigned long load, tmp_rla;
- load = p->se.load.weight;
- load = div_u64(load * cfs_rq->h_load, cfs_rq->load.weight + 1);
+ load = p->se.avg.load_avg_contrib * cfs_rq->h_load;
+ tmp_rla = cfs_rq->runnable_load_avg + 1;
- return load;
+ return load / tmp_rla;
}
#else
static inline void update_blocked_averages(int cpu)
--
1.7.5.4
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