From aa3e0bf1aa76579c6c51a2c1116a630aa716379d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 23 Mar 2016 10:43:23 -0700 Subject: [PATCH] rcu: Don't kick unless grace period or request 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 Reviewed-by: Josh Triplett --- 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); -- 2.45.2