[patch] sched: fix the all pinned logic in load_balance_newidle()

[patch] sched: fix the all pinned logic in load_balance_newidle()

[Siddha, Suresh B]

nr_moved is not the correct check for triggering all pinned logic. Fix the
all pinned logic in the case of load_balance_newidle().

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index 3332bbb..0cdac9c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2668,6 +2668,7 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
 	unsigned long imbalance;
 	int nr_moved = 0;
 	int sd_idle = 0;
+	int all_pinned = 0;
 	cpumask_t cpus = CPU_MASK_ALL;
 
 	/*
@@ -2706,10 +2707,10 @@ redo:
 		double_lock_balance(this_rq, busiest);
 		nr_moved = move_tasks(this_rq, this_cpu, busiest,
 					minus_1_or_zero(busiest->nr_running),
-					imbalance, sd, CPU_NEWLY_IDLE, NULL);
+					imbalance, sd, CPU_NEWLY_IDLE, &all_pinned);
 		spin_unlock(&busiest->lock);
 
-		if (!nr_moved) {
+		if (unlikely(all_pinned)) {
 			cpu_clear(cpu_of(busiest), cpus);
 			if (!cpus_empty(cpus))
 				goto redo;

Re: [patch] sched: fix the all pinned logic in load_balance_newidle()

[Ingo Molnar]

* Siddha, Suresh B <suresh.b.siddha@intel.com> wrote:

> nr_moved is not the correct check for triggering all pinned logic. Fix 
> the all pinned logic in the case of load_balance_newidle().

indeeed.

i've applied your patch to my queue. (I've done a trivial style change 
to it, see below.)

	Ingo

--------------------->
Subject: sched: fix the all pinned logic in load_balance_newidle()
From: Suresh Siddha <suresh.b.siddha@intel.com>

nr_moved is not the correct check for triggering all pinned logic. Fix
the all pinned logic in the case of load_balance_newidle().

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -2679,6 +2679,7 @@ load_balance_newidle(int this_cpu, struc
 	unsigned long imbalance;
 	int nr_moved = 0;
 	int sd_idle = 0;
+	int all_pinned = 0;
 	cpumask_t cpus = CPU_MASK_ALL;
 
 	/*
@@ -2717,10 +2718,11 @@ redo:
 		double_lock_balance(this_rq, busiest);
 		nr_moved = move_tasks(this_rq, this_cpu, busiest,
 					minus_1_or_zero(busiest->nr_running),
-					imbalance, sd, CPU_NEWLY_IDLE, NULL);
+					imbalance, sd, CPU_NEWLY_IDLE,
+					&all_pinned);
 		spin_unlock(&busiest->lock);
 
-		if (!nr_moved) {
+		if (unlikely(all_pinned)) {
 			cpu_clear(cpu_of(busiest), cpus);
 			if (!cpus_empty(cpus))
 				goto redo;