From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935213AbcLOCnx (ORCPT ); Wed, 14 Dec 2016 21:43:53 -0500 Received: from mail-pf0-f194.google.com ([209.85.192.194]:33087 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753628AbcLOCnZ (ORCPT ); Wed, 14 Dec 2016 21:43:25 -0500 From: Boqun Feng To: linux-kernel@vger.kernel.org Cc: "Paul E . McKenney " , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Colin King , Mark Rutland , Boqun Feng Subject: [RFC v2 3/5] rcu: Use for_each_leaf_node_cpu() in ->expmask iteration Date: Thu, 15 Dec 2016 10:42:02 +0800 Message-Id: <20161215024204.28620-4-boqun.feng@gmail.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161215024204.28620-1-boqun.feng@gmail.com> References: <20161215024204.28620-1-boqun.feng@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ->expmask of an RCU leaf node should be more sparse than the corresponding part of cpu_possible_mask, iterating over ->expmask bitmap rather cpu_possible_mask to save some checks. Signed-off-by: Boqun Feng --- kernel/rcu/tree_exp.h | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index a3a8756670d1..c4b3c8d01941 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -419,7 +419,6 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) int cpu; unsigned long jiffies_stall; unsigned long jiffies_start; - unsigned long mask; int ndetected; struct rcu_node *rnp; struct rcu_node *rnp_root = rcu_get_root(rsp); @@ -444,12 +443,9 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) ndetected = 0; rcu_for_each_leaf_node(rsp, rnp) { ndetected += rcu_print_task_exp_stall(rnp); - for_each_leaf_node_possible_cpu(rnp, cpu) { + for_each_leaf_node_cpu(rnp, rnp->expmask, cpu) { struct rcu_data *rdp; - mask = leaf_node_cpu_bit(rnp, cpu); - if (!(rnp->expmask & mask)) - continue; ndetected++; rdp = per_cpu_ptr(rsp->rda, cpu); pr_cont(" %d-%c%c%c", cpu, @@ -475,14 +471,10 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) } pr_cont("\n"); } - rcu_for_each_leaf_node(rsp, rnp) { - for_each_leaf_node_possible_cpu(rnp, cpu) { - mask = leaf_node_cpu_bit(rnp, cpu); - if (!(rnp->expmask & mask)) - continue; + rcu_for_each_leaf_node(rsp, rnp) + for_each_leaf_node_cpu(rnp, rnp->expmask, cpu) dump_cpu_task(cpu); - } - } + jiffies_stall = 3 * rcu_jiffies_till_stall_check() + 3; } } -- 2.10.2