linux-kernel - [tip: core/rcu] nocb: Remove show_rcu_nocb

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Message-ID: <160222534024.7002.809799285141915376.tip-bot2@tip-bot2>
Date:   Fri, 09 Oct 2020 06:35:40 -0000
From:   "tip-bot2 for Paul E. McKenney" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Paul E. McKenney" <paulmck@...nel.org>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: core/rcu] nocb: Remove show_rcu_nocb_state() false positive printout

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     2130c6b4f610ea65e9df71dfa79ee08f2fc17743
Gitweb:        https://git.kernel.org/tip/2130c6b4f610ea65e9df71dfa79ee08f2fc17743
Author:        Paul E. McKenney <paulmck@...nel.org>
AuthorDate:    Mon, 22 Jun 2020 16:46:43 -07:00
Committer:     Paul E. McKenney <paulmck@...nel.org>
CommitterDate: Mon, 24 Aug 2020 18:36:06 -07:00

nocb: Remove show_rcu_nocb_state() false positive printout

The rcu_data structure's ->nocb_timer field is used to defer wakeups of
the corresponding no-CBs CPU's grace-period kthread ("rcuog*"), and that
structure's ->nocb_defer_wakeup field is used to track such deferral.
This means that the show_rcu_nocb_state() printing an error when those
fields are set for a CPU not corresponding to a no-CBs grace-period
kthread is erroneous.

This commit therefore switches the check from ->nocb_timer to
->nocb_bypass_timer and removes the check of ->nocb_defer_wakeup.

Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 kernel/rcu/tree_plugin.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index bbc0c07..4d63ee3 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2411,10 +2411,9 @@ static void show_rcu_nocb_state(struct rcu_data *rdp)
 		return;
 
 	waslocked = raw_spin_is_locked(&rdp->nocb_gp_lock);
-	wastimer = timer_pending(&rdp->nocb_timer);
+	wastimer = timer_pending(&rdp->nocb_bypass_timer);
 	wassleep = swait_active(&rdp->nocb_gp_wq);
-	if (!rdp->nocb_defer_wakeup && !rdp->nocb_gp_sleep &&
-	    !waslocked && !wastimer && !wassleep)
+	if (!rdp->nocb_gp_sleep && !waslocked && !wastimer && !wassleep)
 		return;  /* Nothing untowards. */
 
 	pr_info("   nocb GP activity on CB-only CPU!!! %c%c%c%c %c\n",