[PATCH tip/core/rcu 31/86] rcu: further lower priority in rcu_yield()

Paul E. McKenney
2011-05-01T13:35:40Z

From: Paul E. McKenney <paul.mckenney@linaro.org>

Although rcu_yield() dropped from real-time to normal priority, there
is always the possibility that the competing tasks have been niced.
So nice to 19 in rcu_yield() to help ensure that other tasks have a
better chance of running.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 3295c7b..963b4b1 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1561,6 +1561,7 @@ static void rcu_yield(void (*f)(unsigned long), unsigned long arg)
mod_timer(&yield_timer, jiffies + 2);
sp.sched_priority = 0;
sched_setscheduler_nocheck(current, SCHED_NORMAL, &sp);
+ set_user_nice(current, 19);
schedule();
sp.sched_priority = RCU_KTHREAD_PRIO;
sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
--
1.7.3.2