[PATCH] sched/numa: do not balance tasks onto isolated cpus

[Chen Lin]

From: Chen Lin <cheng.lin130@xxxxxxxxxx>

NUMA balancing has not taken *isolcpus(isolated cpus)* into 
consideration. It may migrate tasks onto isolated cpus and the 
migrated tasks will never escape from the isolated cpus, which will
break the isolation provided by *isolcpus* boot parameter and 
intrduce various problems.

This patch ensure NUMA balancing not to balance tasks onto iaolated
cpus. 

Signed-off-by: Cheng Lin <cheng.lin130@xxxxxxxxxx>
Signed-off-by: Tan Hu <tan.hu@xxxxxxxxxx>
Signed-off-by: Jiang Biao <jiang.biao2@xxxxxxxxxx>
---
 kernel/sched/core.c | 9 ++++++---
 kernel/sched/fair.c | 3 ++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fe365c9..f9ce90c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1302,10 +1302,12 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p)
 	if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
 		goto out;

-	if (!cpumask_test_cpu(arg.dst_cpu, &arg.src_task->cpus_allowed))
+	if ((!cpumask_test_cpu(arg.dst_cpu, &arg.src_task->cpus_allowed))
+            || cpumask_test_cpu(arg.dst_cpu, cpu_isolated_map))
 		goto out;

-	if (!cpumask_test_cpu(arg.src_cpu, &arg.dst_task->cpus_allowed))
+	if ((!cpumask_test_cpu(arg.src_cpu, &arg.dst_task->cpus_allowed))
+            || cpumask_test_cpu(arg.src_cpu, cpu_isolated_map))
 		goto out;

 	trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
@@ -5508,7 +5510,8 @@ int migrate_task_to(struct task_struct *p, int target_cpu)
 	if (curr_cpu == target_cpu)
 		return 0;

-	if (!cpumask_test_cpu(target_cpu, &p->cpus_allowed))
+	if ((!cpumask_test_cpu(target_cpu, &p->cpus_allowed))
+            || cpumask_test_cpu(target_cpu, cpu_isolated_map))
 		return -EINVAL;

 	/* TODO: This is not properly updating schedstats */
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2f0a0be..a91f8fe 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1724,7 +1724,8 @@ static void task_numa_find_cpu(struct task_numa_env *env,

 	for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) {
 		/* Skip this CPU if the source task cannot migrate */
-		if (!cpumask_test_cpu(cpu, &env->p->cpus_allowed))
+		if ((!cpumask_test_cpu(cpu, &env->p->cpus_allowed))
+                    || cpumask_test_cpu(cpu, cpu_isolated_map))
 			continue;

 		env->dst_cpu = cpu;
--
1.8.3.1