From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757619AbaGQV3q (ORCPT ); Thu, 17 Jul 2014 17:29:46 -0400 Received: from mail-yk0-f181.google.com ([209.85.160.181]:40980 "EHLO mail-yk0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751796AbaGQV3o (ORCPT ); Thu, 17 Jul 2014 17:29:44 -0400 From: Pranith Kumar To: "Paul E. McKenney" , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , linux-kernel@vger.kernel.org (open list:READ-COPY UPDATE...) Subject: [PATCH 1/1] rcu: Check for have_rcu_nocb_mask instead of rcu_nocb_mask Date: Thu, 17 Jul 2014 17:30:11 -0400 Message-Id: <1405632611-29872-1-git-send-email-bobby.prani@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, This is something similar to what you found yesterday with tick_nohz_full mask. -- Pranith If we configure a kernel with CONFIG_NOCB_CPU=y, CONFIG_RCU_NOCB_CPU_NONE=y and CONFIG_CPUMASK_OFFSTACK=n and do not pass in a rcu_nocb= boot parameter, the cpumask rcu_nocb_mask can be garbage instead of NULL. Hence this commit replaces checks for rcu_nocb_mask == NULL with a check for have_rcu_nocb_mask. Signed-off-by: Pranith Kumar --- kernel/rcu/tree_plugin.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index cedb020..15c00b5 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2542,7 +2542,7 @@ static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp) struct rcu_data *rdp_leader = NULL; /* Suppress misguided gcc warn. */ struct rcu_data *rdp_prev = NULL; - if (rcu_nocb_mask == NULL) + if (!have_rcu_nocb_mask) return; #ifdef CONFIG_NO_HZ_FULL cpumask_or(rcu_nocb_mask, rcu_nocb_mask, tick_nohz_full_mask); @@ -2575,7 +2575,7 @@ static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp) /* Prevent __call_rcu() from enqueuing callbacks on no-CBs CPUs */ static bool init_nocb_callback_list(struct rcu_data *rdp) { - if (rcu_nocb_mask == NULL || + if (have_rcu_nocb_mask == false || !cpumask_test_cpu(rdp->cpu, rcu_nocb_mask)) return false; rdp->nxttail[RCU_NEXT_TAIL] = NULL; -- 1.9.1