Let the processes which lose they original cpus run on housekeeping cpus
if they can to reduce disturbances on nohz_full cpus.

Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Christoph Lameter <c...@linux.com>
Cc: Kevin Hilman <khil...@linaro.org>
Cc: Mike Galbraith <bitbuc...@online.de>
Cc: Viresh Kumar <viresh.ku...@linaro.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
 kernel/sched/core.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f0f831e..f9ef41a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1286,7 +1286,7 @@ static int select_fallback_rq(int cpu, struct task_struct 
*p)
 {
        int nid = cpu_to_node(cpu);
        const struct cpumask *nodemask = NULL;
-       enum { cpuset, possible, fail } state = cpuset;
+       enum { cpuset, housekeeping, possible, fail } state = cpuset;
        int dest_cpu;
 
        /*
@@ -1322,8 +1322,15 @@ static int select_fallback_rq(int cpu, struct 
task_struct *p)
                case cpuset:
                        /* No more Mr. Nice Guy. */
                        cpuset_cpus_allowed_fallback(p);
+                       state = housekeeping;
+                       break;
+
+               case housekeeping:
+#ifdef CONFIG_NO_HZ_FULL
+                       do_set_cpus_allowed(p, housekeeping_mask);
                        state = possible;
                        break;
+# endif /* CONFIG_NO_HZ_FULL. Fallthrough when !CONFIG_NO_HZ_FULL */
 
                case possible:
                        do_set_cpus_allowed(p, cpu_possible_mask);
-- 
2.1.0

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