From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757739Ab3IYBoU (ORCPT ); Tue, 24 Sep 2013 21:44:20 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:41778 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758654Ab3IYBm6 (ORCPT ); Tue, 24 Sep 2013 21:42:58 -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, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 07/10] rcu: Distinguish between NOCB and non-NOCB rcu_callback trace events Date: Tue, 24 Sep 2013 18:42:36 -0700 Message-Id: <1380073359-31959-7-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1380073359-31959-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20130925014210.GA31690@linux.vnet.ibm.com> <1380073359-31959-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13092501-0320-0000-0000-0000011DA9B9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" One way to distinguish between NOCB and non-NOCB rcu_callback trace events is that the former always print zero for the lazy and non-lazy queue lengths. Unfortunately, this also means that we cannot see the NOCB queue lengths. This commit therefore accesses the NOCB queue lengths, but negates them. NOCB rcu_callback trace events should therefore have negative queue lengths. Signed-off-by: Paul E. McKenney [ paulmck: Match operand size per kbuild test robot's advice. ] --- kernel/rcutree_plugin.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index f4ed24b..24b01b6 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -2147,10 +2147,12 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, if (__is_kfree_rcu_offset((unsigned long)rhp->func)) trace_rcu_kfree_callback(rdp->rsp->name, rhp, (unsigned long)rhp->func, - rdp->qlen_lazy, rdp->qlen); + -atomic_long_read(&rdp->nocb_q_count_lazy), + -atomic_long_read(&rdp->nocb_q_count)); else trace_rcu_callback(rdp->rsp->name, rhp, - rdp->qlen_lazy, rdp->qlen); + -atomic_long_read(&rdp->nocb_q_count_lazy), + -atomic_long_read(&rdp->nocb_q_count)); return 1; } -- 1.8.1.5