Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754470AbdDMQhU (ORCPT ); Thu, 13 Apr 2017 12:37:20 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34078 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753350AbdDMQhS (ORCPT ); Thu, 13 Apr 2017 12:37:18 -0400 Date: Thu, 13 Apr 2017 09:37:10 -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 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170413095029.i6kxm2ujpdqmid2b@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17041316-0040-0000-0000-00000314FD68 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006929; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00847062; UDB=6.00417883; IPR=6.00625496; 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 16:37:15 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041316-0041-0000-0000-00000709097E Message-Id: <20170413163710.GF3956@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-13_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=8.0.1-1702020001 definitions=main-1704130139 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 786 Lines: 20 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. But yes, it would be really cool to have lockless VMA lookup!!! Thanx, Paul