From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754170AbbELVqA (ORCPT ); Tue, 12 May 2015 17:46:00 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:58144 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753797AbbELVp5 (ORCPT ); Tue, 12 May 2015 17:45:57 -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 tip/core/rcu 11/15] rcu: Add more debug info on "kthread starved" RCU CPU stall warnings Date: Tue, 12 May 2015 14:38:17 -0700 Message-Id: <1431466701-653-11-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1431466701-653-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20150512213756.GA32729@linux.vnet.ibm.com> <1431466701-653-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15051221-0009-0000-0000-00000AC69A70 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" This commit adds grace number and command-flags information to the "kthread starved" message that is sometimes printed out as part of RCU CPU stall warnings. This message is caused by the corresponding RCU grace-period kthread not having run for at least two seconds, and this added information can be helpful when debugging. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a7615a0b684f..5b573e75e0f8 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1133,8 +1133,9 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) j = jiffies; gpa = READ_ONCE(rsp->gp_activity); if (j - gpa > 2 * HZ) - pr_err("%s kthread starved for %ld jiffies!\n", - rsp->name, j - gpa); + pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x\n", + rsp->name, j - gpa, + rsp->gpnum, rsp->completed, rsp->gp_flags); } /* -- 1.8.1.5