Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755120AbdDMRnB (ORCPT ); Thu, 13 Apr 2017 13:43:01 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:52582 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753005AbdDMRm7 (ORCPT ); Thu, 13 Apr 2017 13:42:59 -0400 Date: Thu, 13 Apr 2017 10:42:49 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, laurent.dufour@fr.ibm.com, npiggin@au1.ibm.com Subject: Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling Reply-To: paulmck@linux.vnet.ibm.com References: <20170412174003.GA23207@linux.vnet.ibm.com> <1492018825-25634-40-git-send-email-paulmck@linux.vnet.ibm.com> <20170413095029.i6kxm2ujpdqmid2b@hirez.programming.kicks-ass.net> <20170413163710.GF3956@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170413163710.GF3956@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17041317-0024-0000-0000-000002467D79 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006930; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00847084; UDB=6.00417896; IPR=6.00625517; BA=6.00005288; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015033; XFM=3.00000013; UTC=2017-04-13 17:42:56 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041317-0025-0000-0000-000043596EB7 Message-Id: <20170413174249.GA12617@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-13_14:,, 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=8.0.1-1702020001 definitions=main-1704130148 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1080 Lines: 27 On Thu, Apr 13, 2017 at 09:37:10AM -0700, Paul E. McKenney wrote: > On Thu, Apr 13, 2017 at 11:50:29AM +0200, Peter Zijlstra wrote: > > On Wed, Apr 12, 2017 at 10:40:25AM -0700, Paul E. McKenney wrote: > > > Peter Zijlstra proposed using SRCU to reduce mmap_sem contention [1], > > > > Bugger, now you're making me feel bad for not having updated those > > patches in ages.. I'll try and bump it on the todo list. > > Apologies, I wasn't trying to make you feel bad. But I did get an old > version of the patch. A much more recent one is here, which I have > added to the commit log: > > https://patchwork.kernel.org/patch/5108281/ > > For my part, I feel bad that I didn't realize much earlier that parallel > SRCU callbacks were needed. As it was, someone had to tell me late > last year. And it turns out that Laurent Dufour (CCed) forward-ported your patch from the above patchworks URL to 4.11. He is chasing down some mmseq bugs on a best-effort basis. Thanx, Paul > But yes, it would be really cool to have lockless VMA lookup!!! > > Thanx, Paul