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Subject[RFC PATCH 2/4] sched: Consolidate nohz cpu load prelude code
Date
Gather the common code that computes the pending idle cpu load
to decay.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Alex Shi <alex.shi@intel.com>
Cc: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/proc.c | 40 ++++++++++++++--------------------------
1 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c
index bb3a6a0..030528a 100644
--- a/kernel/sched/proc.c
+++ b/kernel/sched/proc.c
@@ -470,11 +470,14 @@ decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
* scheduler tick (TICK_NSEC). With tickless idle this will not be called
* every tick. We fix it up based on jiffies.
*/
-static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
- unsigned long pending_updates)
+static void __update_cpu_load(struct rq *this_rq, unsigned long this_load)
{
+ unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
+ unsigned long pending_updates;
int i, scale;

+ pending_updates = curr_jiffies - this_rq->last_load_update_tick;
+ this_rq->last_load_update_tick = curr_jiffies;
this_rq->nr_load_updates++;

/* Update our load: */
@@ -521,20 +524,15 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
*/
void update_idle_cpu_load(struct rq *this_rq)
{
- unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
unsigned long load = this_rq->load.weight;
- unsigned long pending_updates;

/*
* bail if there's load or we're actually up-to-date.
*/
- if (load || curr_jiffies == this_rq->last_load_update_tick)
+ if (load || jiffies == this_rq->last_load_update_tick)
return;

- pending_updates = curr_jiffies - this_rq->last_load_update_tick;
- this_rq->last_load_update_tick = curr_jiffies;
-
- __update_cpu_load(this_rq, load, pending_updates);
+ __update_cpu_load(this_rq, load);
}

/*
@@ -543,22 +541,16 @@ void update_idle_cpu_load(struct rq *this_rq)
void update_cpu_load_nohz(void)
{
struct rq *this_rq = this_rq();
- unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
- unsigned long pending_updates;

- if (curr_jiffies == this_rq->last_load_update_tick)
+ if (jiffies == this_rq->last_load_update_tick)
return;

raw_spin_lock(&this_rq->lock);
- pending_updates = curr_jiffies - this_rq->last_load_update_tick;
- if (pending_updates) {
- this_rq->last_load_update_tick = curr_jiffies;
- /*
- * We were idle, this means load 0, the current load might be
- * !0 due to remote wakeups and the sort.
- */
- __update_cpu_load(this_rq, 0, pending_updates);
- }
+ /*
+ * We were idle, this means load 0, the current load might be
+ * !0 due to remote wakeups and the sort.
+ */
+ __update_cpu_load(this_rq, 0);
raw_spin_unlock(&this_rq->lock);
}
#endif /* CONFIG_NO_HZ */
@@ -568,11 +560,7 @@ void update_cpu_load_nohz(void)
*/
void update_cpu_load_active(struct rq *this_rq)
{
- /*
- * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
- */
- this_rq->last_load_update_tick = jiffies;
- __update_cpu_load(this_rq, this_rq->load.weight, 1);
+ __update_cpu_load(this_rq, this_rq->load.weight);

calc_load_account_active(this_rq);
}
--
1.7.5.4


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