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sched: fix the all pinned logic in load_balance_newidle()

PATCH In review Siddha, Suresh B 2 participants 2 messages Jul 16, 2007 – Jul 17, 2007

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Siddha, Suresh B

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#0 lore raw

PATCH 1/1 sched: fix the all pinned logic in load_balance_newidle()

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 <[email protected]>

---

kernel/sched.c +3 -2
index 3332bbb..0cdac9c 100644
@@ -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;
#1 lore raw
Quoted 2 lines · 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().

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 <[email protected]>

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 <[email protected]>
Signed-off-by Ingo Molnar <[email protected]>
---
 kernel/sched.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
kernel/sched.c +4 -2
Index: 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;