From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751247AbdJDVuQ (ORCPT ); Wed, 4 Oct 2017 17:50:16 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39502 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbdJDVuP (ORCPT ); Wed, 4 Oct 2017 17:50:15 -0400 Date: Wed, 4 Oct 2017 14:50:06 -0700 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, fweisbec@gmail.com, oleg@redhat.com Subject: [PATCH tip/core/rcu 0/4] RCU CPU stall warning updates for v4.15 Reply-To: paulmck@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17100421-0056-0000-0000-000003D3C956 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007844; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000233; SDB=6.00926540; UDB=6.00466105; IPR=6.00706752; BA=6.00005620; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017395; XFM=3.00000015; UTC=2017-10-04 21:50:12 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17100421-0057-0000-0000-0000080AD92E Message-Id: <20171004215006.GA12792@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-04_10:,, 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=8.0.1-1707230000 definitions=main-1710040302 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello! This series updates RCU CPU stall warnings, and also, due to conflicts, pulls along a long-standing patch that allows cond_resched() to do the work that cond_resched_rcu_qs() does. 1. Make cond_resched() provide RCU quiescent state. This has been heavily optimized over its lifetime, which is almost one year. It should be close enough. Yes, some benchmarks show that it results in higher context-switch rates, but then again, the problem being solved is in fact too few context switches. ;-) 2. Make RCU CPU stall warnings check for irq-disabled CPUs. 3. Turn off tracing before dumping traces. 4. Suppress RCU CPU stall warnings while dumping RCU-related traces. Thanx, Paul ------------------------------------------------------------------------ include/linux/sched.h | 3 - kernel/rcu/rcu.h | 21 +++++++ kernel/rcu/tree.c | 129 +++++++++++++++++++++++++++++++++++------------ kernel/rcu/tree.h | 5 + kernel/rcu/tree_plugin.h | 7 ++ kernel/rcu/update.c | 1 kernel/sched/core.c | 1 7 files changed, 132 insertions(+), 35 deletions(-)