From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754148Ab0ADXLO (ORCPT ); Mon, 4 Jan 2010 18:11:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754022Ab0ADXJU (ORCPT ); Mon, 4 Jan 2010 18:09:20 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:39508 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753976Ab0ADXJP (ORCPT ); Mon, 4 Jan 2010 18:09:15 -0500 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, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 04/11] rcu: eliminate local variable signaled from force_quiescent_state() Date: Mon, 4 Jan 2010 15:09:03 -0800 Message-Id: <1262646550602-git-send-email-> X-Mailer: git-send-email 1.5.2.5 In-Reply-To: <20100104230850.GA22111@linux.vnet.ibm.com> References: <20100104230850.GA22111@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paul E. McKenney Because the root rcu_node lock is held across entry to the switch statement in force_quiescent_state(), it is no longer necessary to snapshot rsp->signaled to a local variable. Eliminate both the snapshotting and the local variable. Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 9 +++------ 1 files changed, 3 insertions(+), 6 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 41688ff..1d8cfb1 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1193,7 +1193,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) unsigned long flags; long lastcomp; struct rcu_node *rnp = rcu_get_root(rsp); - u8 signaled; u8 forcenow; u8 gpdone; @@ -1209,7 +1208,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) rsp->n_force_qs++; spin_lock(&rnp->lock); /* irqs already disabled */ lastcomp = rsp->gpnum - 1; - signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; @@ -1217,7 +1215,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) goto unlock_fqs_ret; /* no GP in progress, time updated. */ } rsp->fqs_active = 1; - switch (signaled) { + switch (rsp->signaled) { case RCU_GP_IDLE: case RCU_GP_INIT: @@ -1242,11 +1240,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Update state, record completion counter. */ forcenow = 0; if (lastcomp + 1 == rsp->gpnum && - lastcomp == rsp->completed && - rsp->signaled == signaled) { + lastcomp == rsp->completed) { + forcenow = rsp->signaled == RCU_SAVE_COMPLETED; rsp->signaled = RCU_FORCE_QS; rsp->completed_fqs = lastcomp; - forcenow = signaled == RCU_SAVE_COMPLETED; } if (!forcenow) break; -- 1.5.2.5