From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756022Ab1IGG1m (ORCPT ); Wed, 7 Sep 2011 02:27:42 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:37772 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755597Ab1IGGU5 (ORCPT ); Wed, 7 Sep 2011 02:20:57 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 30/55] rcu: Eliminate in_irq() checks in rcu_enter_nohz() Date: Tue, 6 Sep 2011 11:00:24 -0700 Message-Id: <1315332049-2604-30-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.3.2 In-Reply-To: <20110906180015.GA2560@linux.vnet.ibm.com> References: <20110906180015.GA2560@linux.vnet.ibm.com> x-cbid: 11090706-6078-0000-0000-000000711820 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The in_irq() check in rcu_enter_nohz() is redundant because if we really are in an interrupt, the attempt to re-enter dyntick-idle mode will invoke rcu_needs_cpu() in any case, which will force the check for RCU callbacks. So this commit removes the check along with the set_need_resched(). Suggested-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 7 ------- 1 files changed, 0 insertions(+), 7 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 7e2f297..0c6c30d 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -373,13 +373,6 @@ void rcu_enter_nohz(void) smp_mb__after_atomic_inc(); /* Force ordering with next sojourn. */ WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1); local_irq_restore(flags); - - /* If the interrupt queued a callback, get out of dyntick mode. */ - if (in_irq() && - (__get_cpu_var(rcu_sched_data).nxtlist || - __get_cpu_var(rcu_bh_data).nxtlist || - rcu_preempt_needs_cpu(smp_processor_id()))) - set_need_resched(); } /* -- 1.7.3.2