From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935250AbcLOCnz (ORCPT ); Wed, 14 Dec 2016 21:43:55 -0500 Received: from mail-pg0-f66.google.com ([74.125.83.66]:34326 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753398AbcLOCnZ (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 2/5] rcu: Use for_each_leaf_node_cpu() in RCU stall checking Date: Thu, 15 Dec 2016 10:42:01 +0800 Message-Id: <20161215024204.28620-3-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 Use for_each_leaf_node_cpu() in RCU stall checking code, to save some extra checks, based on the fact that ->qsmask is mostly more sparse than cpu_possible_mask. Signed-off-by: Boqun Feng --- kernel/rcu/tree.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b56e2dc31ba5..4e5b81c843de 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1417,10 +1417,11 @@ static void rcu_dump_cpu_stacks(struct rcu_state *rsp) rcu_for_each_leaf_node(rsp, rnp) { raw_spin_lock_irqsave_rcu_node(rnp, flags); - for_each_leaf_node_possible_cpu(rnp, cpu) - if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) - if (!trigger_single_cpu_backtrace(cpu)) - dump_cpu_task(cpu); + + for_each_leaf_node_cpu(rnp, rnp->qsmask, cpu) + if (!trigger_single_cpu_backtrace(cpu)) + dump_cpu_task(cpu); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } } @@ -1490,13 +1491,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) rcu_for_each_leaf_node(rsp, rnp) { raw_spin_lock_irqsave_rcu_node(rnp, flags); ndetected += rcu_print_task_stall(rnp); - if (rnp->qsmask != 0) { - for_each_leaf_node_possible_cpu(rnp, cpu) - if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) { - print_cpu_stall_info(rsp, cpu); - ndetected++; - } + + for_each_leaf_node_cpu(rnp, rnp->qsmask, cpu) { + print_cpu_stall_info(rsp, cpu); + ndetected++; } + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } -- 2.10.2