[PATCH v3 tip/core/rcu 08/18] rcu: Remove short-term CPU kicking

Paul E. McKenney
2017-01-24T21:55:11Z

Commit 4914950aaa12d ("rcu: Stop treating in-kernel CPU-bound workloads
as errors") added a (relatively) short-timeout call to resched_cpu().
This was inspired by as issue that was fixed by b7e7ade34e61 ("sched/core:
Fix remote wakeups"). But given that this issue was fixed, it is time
for the current commit to remove this call to resched_cpu().

Reported-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---
kernel/rcu/tree.c | 5 -----
1 file changed, 5 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 0e61b62e3f4a..5a4aaad75e76 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1220,11 +1220,6 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
rdp->rsp->jiffies_resched += 5; /* Re-enable beating. */
}

- /* And if it has been a really long time, kick the CPU as well. */
- if (ULONG_CMP_GE(jiffies,
- rdp->rsp->gp_start + 2 * jiffies_till_sched_qs) ||
- ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs))
- resched_cpu(rdp->cpu); /* Force CPU into scheduler. */
/*
* If more than halfway to RCU CPU stall-warning time, do
* a resched_cpu() to try to loosen things up a bit.
--
2.5.2