[PATCH] sched/rt: Add borrowing time condition

[qiang.zhang]

From: Zhang Qiang <qiang.zh...@windriver.com>

Add priority judgment to determine whether to borrow time from neighbors,
ensure that the rt_runntime of rt_rq with higher priority tasks is not
reduced

Signed-off-by: Zhang Qiang <qiang.zh...@windriver.com>
---
 kernel/sched/rt.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 4043abe45459..d2a1acad6687 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -711,8 +711,10 @@ static void do_balance_runtime(struct rt_rq *rt_rq)
                        diff = div_u64((u64)diff, weight);
                        if (rt_rq->rt_runtime + diff > rt_period)
                                diff = rt_period - rt_rq->rt_runtime;
-                       iter->rt_runtime -= diff;
-                       rt_rq->rt_runtime += diff;
+                       if (rt_rq->highest_prio.curr < iter->highest_prio.curr) 
{
+                               iter->rt_runtime -= diff;
+                               rt_rq->rt_runtime += diff;
+                       }
                        if (rt_rq->rt_runtime == rt_period) {
                                raw_spin_unlock(&iter->rt_runtime_lock);
                                break;
-- 
2.17.0