From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934245AbbCPSmK (ORCPT ); Mon, 16 Mar 2015 14:42:10 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:34046 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757223AbbCPSiT (ORCPT ); Mon, 16 Mar 2015 14:38:19 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" Subject: [PATCH v2 tip/core/rcu 12/22] rcu: Remove event tracing from rcu_cpu_notify(), used by offline CPUs Date: Mon, 16 Mar 2015 11:37:56 -0700 Message-Id: <1426531086-23825-12-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1426531086-23825-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20150316183743.GA21453@linux.vnet.ibm.com> <1426531086-23825-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15031618-0005-0000-0000-000009814E6D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" Offline CPUs cannot safely invoke trace events, but such CPUs do execute within rcu_cpu_notify(). Therefore, this commit removes the trace events from rcu_cpu_notify(). These trace events are for utilization, against which rcu_cpu_notify() execution time should be negligible. Reported-by: Fengguang Wu Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b42001fd55fb..a7151d26b940 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3629,7 +3629,6 @@ static int rcu_cpu_notify(struct notifier_block *self, struct rcu_node *rnp = rdp->mynode; struct rcu_state *rsp; - trace_rcu_utilization(TPS("Start CPU hotplug")); switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: @@ -3661,7 +3660,6 @@ static int rcu_cpu_notify(struct notifier_block *self, default: break; } - trace_rcu_utilization(TPS("End CPU hotplug")); return NOTIFY_OK; } -- 1.8.1.5