From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752228AbeEOEJr (ORCPT ); Tue, 15 May 2018 00:09:47 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:52700 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752153AbeEOEJq (ORCPT ); Tue, 15 May 2018 00:09:46 -0400 Date: Mon, 14 May 2018 21:11:11 -0700 From: "Paul E. McKenney" To: Byungchul Park Cc: jiangshanlai@gmail.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, kernel-team@lge.com, joel@joelfernandes.org Subject: Re: [PATCH] rcu: Report a quiescent state of TASKS_RCU on a tick from user Reply-To: paulmck@linux.vnet.ibm.com References: <1526344426-31836-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1526344426-31836-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18051504-0024-0000-0000-000003590BB1 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009027; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000260; SDB=6.01032476; UDB=6.00527839; IPR=6.00811607; MB=3.00021118; MTD=3.00000008; XFM=3.00000015; UTC=2018-05-15 04:09:43 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18051504-0025-0000-0000-000048042BD4 Message-Id: <20180515041111.GC26088@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-05-15_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805150041 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 15, 2018 at 09:33:46AM +0900, Byungchul Park wrote: > Hello Paul, > > You removed the reporing while simplifying the commit 508880df6 :) > Fold this patch onto the commit or add, whatever you want. First, thank you for checking! But second, the removal was intentional. Tiny RCU only exists in PREEMPT=n kernels, and in such kernels there can be no RCU-tasks. This is the reason for this line in the new commit log: [ paulmck: Simplify rcutiny portion given no RCU-tasks for !PREEMPT. ] Thanx, Paul > Thanks, > Byungchul > > ----->8----- > >From 18a2d8da3baf79d0edd5ccf94abe6f989da5b1c1 Mon Sep 17 00:00:00 2001 > From: Byungchul Park > Date: Tue, 15 May 2018 09:21:43 +0900 > Subject: [PATCH] rcu: Report a quiescent state of TASKS_RCU on a tick from > user > > The reporting was removed while simplifying the commit 508880df6 (rcu: > Improve rcu_note_voluntary_context_switch() reporting). Add it back. > > Signed-off-by: Byungchul Park > --- > kernel/rcu/tiny.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c > index befc932..3345596 100644 > --- a/kernel/rcu/tiny.c > +++ b/kernel/rcu/tiny.c > @@ -120,8 +120,10 @@ void rcu_bh_qs(void) > */ > void rcu_check_callbacks(int user) > { > - if (user) > + if (user) { > rcu_sched_qs(); > + rcu_tasks_qs(); > + } > if (user || !in_softirq()) > rcu_bh_qs(); > } > -- > 1.9.1 >