From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752041AbdFOV5b (ORCPT ); Thu, 15 Jun 2017 17:57:31 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:47854 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750830AbdFOV53 (ORCPT ); Thu, 15 Jun 2017 17:57:29 -0400 Date: Thu, 15 Jun 2017 14:57:17 -0700 From: "Paul E. McKenney" To: "Luis R. Rodriguez" Cc: peterz@infradead.org, oleg@redhat.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, paul.gortmaker@windriver.com, ebiederm@xmission.com, dmitry.torokhov@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [RFC v2 0/2] swait: add idle to make idle-hacks on kthreads explicit Reply-To: paulmck@linux.vnet.ibm.com References: <87zid92ns2.fsf@xmission.com> <20170615184820.22994-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170615184820.22994-1-mcgrof@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17061521-0008-0000-0000-000002434916 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007239; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000212; SDB=6.00875311; UDB=6.00435796; IPR=6.00655400; BA=6.00005423; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015841; XFM=3.00000015; UTC=2017-06-15 21:57:25 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17061521-0009-0000-0000-000035AD7EAA Message-Id: <20170615215717.GI3721@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-15_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706150378 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 15, 2017 at 11:48:18AM -0700, Luis R. Rodriguez wrote: > While reviewing RCU's interruptible swaits I noticed signals were actually > not expected. Paul explained that the reason signals are not expected is > we use kthreads, which don't get signals, furthermore the code avoided the > uninterruptible swaits as otherwise it would contribute to the system load > average on idle, bumping it from 0 to 2 or 3 (depending on preemption). > > Since this can be confusing its best to be explicit about the requirements and > goals. This patch depends on the other killable swaits [0] recently proposed as > well interms of context. Thee patch can however be tested independently if > the hunk is addressed separately. > > [0] https://lkml.kernel.org/r/20170614222017.14653-3-mcgrof@kernel.org Tested-by: Paul E. McKenney Are you looking to push these or were you wanting me to? Thanx, Paul > Luis R. Rodriguez (2): > swait: add idle variants which don't contribute to load average > rcu: use idle versions of swait to make idle-hack clear > > include/linux/swait.h | 25 +++++++++++++++++++++++++ > kernel/rcu/tree.c | 4 ++-- > 2 files changed, 27 insertions(+), 2 deletions(-) > > -- > 2.11.0 >