From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933456AbcFOW3p (ORCPT ); Wed, 15 Jun 2016 18:29:45 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:63953 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933063AbcFOW2j (ORCPT ); Wed, 15 Jun 2016 18:28:39 -0400 X-IBM-Helo: d01dlp01.pok.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.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 3/8] waketorture: Don't kick unless grace period or request Date: Wed, 15 Jun 2016 15:28:23 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20160615222756.GA10695@linux.vnet.ibm.com> References: <20160615222756.GA10695@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16061522-0056-0000-0000-00000088238A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16061522-0057-0000-0000-000004A17F3D Message-Id: <1466029708-11359-3-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-15_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606150236 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current code can result in spurious kicks when there are no grace periods in progress and no grace-period-related requests. This is sort of OK for a diagnostic aid, but the resulting ftrace-dump messages in dmesg are annoying. This commit therefore avoids spurious kicks in the common case. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f433959e9322..88d3f9590322 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1306,7 +1306,8 @@ static void rcu_stall_kick_kthreads(struct rcu_state *rsp) if (!rcu_kick_kthreads) return; j = READ_ONCE(rsp->jiffies_kick_kthreads); - if (time_after(jiffies, j) && rsp->gp_kthread) { + if (time_after(jiffies, j) && rsp->gp_kthread && + (rcu_gp_in_progress(rsp) || READ_ONCE(rsp->gp_flags))) { WARN_ONCE(1, "Kicking %s grace-period kthread\n", rsp->name); rcu_ftrace_dump(DUMP_ALL); wake_up_process(rsp->gp_kthread); -- 2.5.2