From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754248AbZKMGe4 (ORCPT ); Fri, 13 Nov 2009 01:34:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753463AbZKMGeo (ORCPT ); Fri, 13 Nov 2009 01:34:44 -0500 Received: from e1.ny.us.ibm.com ([32.97.182.141]:53219 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753479AbZKMGen (ORCPT ); Fri, 13 Nov 2009 01:34:43 -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 2/2] rcu: simplify association of forced quiescent states with grace periods Date: Thu, 12 Nov 2009 22:35:04 -0800 Message-Id: <12580941042308-git-send-email-> X-Mailer: git-send-email 1.5.2.5 In-Reply-To: <20091113063439.GA560@linux.vnet.ibm.com> References: <20091113063439.GA560@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 The force_quiescent_state() function also took a snapshot of the ->completed field, which was as obnoxious as it was in rcu_sched_qs() and friends. So snapshot ->gpnum-1. Also, since the dyntick_record_completed() and dyntick_recall_completed() functions are now simple assignments that are independent of CONFIG_NO_HZ, and since their names are now misleading, get rid of them. Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 27 +++------------------------ 1 files changed, 3 insertions(+), 24 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 0490371..f93f0e2 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -178,29 +178,9 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp) return &rsp->node[0]; } -/* - * Record the specified "completed" value, which is later used to validate - * dynticks counter manipulations and CPU-offline checks. Specify - * "rsp->completed - 1" to unconditionally invalidate any future dynticks - * manipulations and CPU-offline checks. Such invalidation is useful at - * the beginning of a grace period. - */ -static void dyntick_record_completed(struct rcu_state *rsp, long comp) -{ - rsp->completed_fqs = comp; -} - #ifdef CONFIG_SMP /* - * Recall the previously recorded value of the completion for dynticks. - */ -static long dyntick_recall_completed(struct rcu_state *rsp) -{ - return rsp->completed_fqs; -} - -/* * If the specified CPU is offline, tell the caller that it is in * a quiescent state. Otherwise, whack it with a reschedule IPI. * Grace periods can end up waiting on an offline CPU when that @@ -702,7 +682,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */ rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; record_gp_stall_check_time(rsp); - dyntick_record_completed(rsp, rsp->completed - 1); /* Special-case the common single-level case. */ if (NUM_RCU_NODES == 1) { @@ -1201,7 +1180,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) goto unlock_ret; /* no emergency and done recently. */ rsp->n_force_qs++; spin_lock(&rnp->lock); - lastcomp = rsp->completed; + lastcomp = rsp->gpnum - 1; signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if (lastcomp == rsp->gpnum) { @@ -1235,7 +1214,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) if (lastcomp == rsp->completed && rsp->signaled == signaled) { rsp->signaled = RCU_FORCE_QS; - dyntick_record_completed(rsp, lastcomp); + rsp->completed_fqs = lastcomp; forcenow = signaled == RCU_SAVE_COMPLETED; } spin_unlock(&rnp->lock); @@ -1246,7 +1225,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_FORCE_QS: /* Check dyntick-idle state, send IPI to laggarts. */ - if (rcu_process_dyntick(rsp, dyntick_recall_completed(rsp), + if (rcu_process_dyntick(rsp, rsp->completed_fqs, rcu_implicit_dynticks_qs)) goto unlock_ret; -- 1.5.2.5