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[PATCH tip/core/rcu 7/7] rcu: Don't kick unless grace period or request

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The current code can result in spurious kicks when there are no grace
periods in progress and no grace-period-related requests.  This is
sort of OK for a diagnostic aid, but the resulting ftrace-dump messages
in dmesg are annoying.  This commit therefore avoids spurious kicks
in the common case.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcu/tree.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 865af187498e..96c52e43f7ca 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1304,7 +1304,8 @@ static void rcu_stall_kick_kthreads(struct rcu_state *rsp)
 	if (!rcu_kick_kthreads)
 		return;
 	j = READ_ONCE(rsp->jiffies_kick_kthreads);
-	if (time_after(jiffies, j) && rsp->gp_kthread) {
+	if (time_after(jiffies, j) && rsp->gp_kthread &&
+	    (rcu_gp_in_progress(rsp) || READ_ONCE(rsp->gp_flags))) {
 		WARN_ONCE(1, "Kicking %s grace-period kthread\n", rsp->name);
 		rcu_ftrace_dump(DUMP_ALL);
 		wake_up_process(rsp->gp_kthread);
-- 
2.5.2

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[PATCH tip/core/rcu 0/7] Miscellaneous fixes for 4.10 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
  [PATCH tip/core/rcu 3/7] rcu: Remove obsolete comment from __call_rcu() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
  [PATCH tip/core/rcu 2/7] rcu: Remove obsolete rcu_check_callbacks() header comment "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
  [PATCH tip/core/rcu 4/7] rcu: RCU_TRACE enables event tracing as well as debugfs "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
  [PATCH tip/core/rcu 7/7] rcu: Don't kick unless grace period or request "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
  [PATCH tip/core/rcu 1/7] rcu: Tighten up __call_rcu() rcu_head alignment check "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
  [PATCH tip/core/rcu 6/7] rcu: Make expedited grace periods recheck dyntick idle state "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
    Re: [PATCH tip/core/rcu 6/7] rcu: Make expedited grace periods  recheck dyntick idle state Josh Triplett <josh@joshtriplett.org> - 2016-11-14 18:30 +0100
      Re: [PATCH tip/core/rcu 6/7] rcu: Make expedited grace periods  recheck dyntick idle state Peter Zijlstra <peterz@infradead.org> - 2016-11-14 18:40 +0100
        Re: [PATCH tip/core/rcu 6/7] rcu: Make expedited grace periods  recheck dyntick idle state "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 19:20 +0100
          Re: [PATCH tip/core/rcu 6/7] rcu: Make expedited grace periods  recheck dyntick idle state Peter Zijlstra <peterz@infradead.org> - 2016-11-15 09:20 +0100
            Re: [PATCH tip/core/rcu 6/7] rcu: Make expedited grace periods  recheck dyntick idle state "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-15 15:40 +0100
  [PATCH tip/core/rcu 5/7] torture: Trace long read-side delays "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 18:00 +0100
    Re: [PATCH tip/core/rcu 5/7] torture: Trace long read-side delays Josh Triplett <josh@joshtriplett.org> - 2016-11-14 18:30 +0100
      Re: [PATCH tip/core/rcu 5/7] torture: Trace long read-side delays "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-14 19:50 +0100
        Re: [PATCH tip/core/rcu 5/7] torture: Trace long read-side delays Josh Triplett <josh@joshtriplett.org> - 2016-11-14 20:00 +0100
  Re: [PATCH tip/core/rcu 0/7] Miscellaneous fixes for 4.10 Josh Triplett <josh@joshtriplett.org> - 2016-11-14 18:30 +0100

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