From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755345AbaHKWuM (ORCPT ); Mon, 11 Aug 2014 18:50:12 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:37469 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754861AbaHKWtQ (ORCPT ); Mon, 11 Aug 2014 18:49:16 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" Subject: [PATCH v5 tip/core/rcu 16/16] rcu: Additional information on RCU-tasks stall-warning messages Date: Mon, 11 Aug 2014 15:49:05 -0700 Message-Id: <1407797345-28227-16-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1407797345-28227-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20140811224840.GA25594@linux.vnet.ibm.com> <1407797345-28227-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14081122-0928-0000-0000-000003FE0203 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" Signed-off-by: Paul E. McKenney --- kernel/rcu/update.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 9ea2a26487c5..43ea9c37bbd0 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -465,6 +465,8 @@ EXPORT_SYMBOL_GPL(rcu_barrier_tasks); static void check_holdout_task(struct task_struct *t, bool needreport, bool *firstreport) { + int cpu; + if (!ACCESS_ONCE(t->rcu_tasks_holdout)) goto not_holdout; /* Other detection of non-holdout status. */ if (t->rcu_tasks_nvcsw != ACCESS_ONCE(t->nvcsw)) @@ -475,8 +477,6 @@ static void check_holdout_task(struct task_struct *t, !is_idle_task(t) && t->rcu_tasks_idle_cpu >= 0) goto not_holdout; /* NO_HZ_FULL userspace execution. */ if (is_idle_task(t)) { - int cpu; - cpu = task_cpu(t); if (cpu >= 0 && cpu_curr(cpu) != t) goto not_holdout; /* Idle task not running. */ @@ -499,6 +499,12 @@ static void check_holdout_task(struct task_struct *t, pr_err("INFO: rcu_tasks detected stalls on tasks:\n"); *firstreport = false; } + cpu = task_cpu(t); + pr_alert("%p: %c%c nvcsw: %lu/%lu holdout: %d idle_cpu: %d/%d\n", + t, ".I"[is_idle_task(t)], + "N."[cpu < 0 || !tick_nohz_full_cpu(cpu)], + t->rcu_tasks_nvcsw, t->nvcsw, t->rcu_tasks_holdout, + t->rcu_tasks_idle_cpu, cpu); sched_show_task(t); return; not_holdout: -- 1.8.1.5