From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752825AbdGHLlV (ORCPT ); Sat, 8 Jul 2017 07:41:21 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48116 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751205AbdGHLlS (ORCPT ); Sat, 8 Jul 2017 07:41:18 -0400 Date: Sat, 8 Jul 2017 04:41:12 -0700 From: "Paul E. McKenney" To: Ingo Molnar Cc: Peter Zijlstra , David Laight , "linux-kernel@vger.kernel.org" , "netfilter-devel@vger.kernel.org" , "netdev@vger.kernel.org" , "oleg@redhat.com" , "akpm@linux-foundation.org" , "mingo@redhat.com" , "dave@stgolabs.net" , "manfred@colorfullife.com" , "tj@kernel.org" , "arnd@arndb.de" , "linux-arch@vger.kernel.org" , "will.deacon@arm.com" , "stern@rowland.harvard.edu" , "parri.andrea@gmail.com" , "torvalds@linux-foundation.org" Subject: Re: [PATCH v2 0/9] Remove spin_unlock_wait() Reply-To: paulmck@linux.vnet.ibm.com References: <20170629235918.GA6445@linux.vnet.ibm.com> <20170705232955.GA15992@linux.vnet.ibm.com> <063D6719AE5E284EB5DD2968C1650D6DD0033F01@AcuExch.aculab.com> <20170706160555.xc63yydk77gmttae@hirez.programming.kicks-ass.net> <20170706162024.GD2393@linux.vnet.ibm.com> <20170706165036.v4u5rbz56si4emw5@hirez.programming.kicks-ass.net> <20170707083128.wqk6msuuhtyykhpu@gmail.com> <20170707144107.GA27202@linux.vnet.ibm.com> <20170708084323.iuyb4smp2a4ca4fh@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170708084323.iuyb4smp2a4ca4fh@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17070811-0040-0000-0000-0000037A47D8 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007340; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000214; SDB=6.00884587; UDB=6.00441390; IPR=6.00664781; BA=6.00005458; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00016140; XFM=3.00000015; UTC=2017-07-08 11:41:17 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17070811-0041-0000-0000-0000076E5105 Message-Id: <20170708114112.GO2393@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-08_06:,, 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-1707080210 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 08, 2017 at 10:43:24AM +0200, Ingo Molnar wrote: > > * Paul E. McKenney wrote: > > > On Fri, Jul 07, 2017 at 10:31:28AM +0200, Ingo Molnar wrote: > > > > [ . . . ] > > > > > In fact I'd argue that any future high performance spin_unlock_wait() user is > > > probably better off open coding the unlock-wait poll loop (and possibly thinking > > > hard about eliminating it altogether). If such patterns pop up in the kernel we > > > can think about consolidating them into a single read-only primitive again. > > > > I would like any reintroduction to include a header comment saying exactly > > what the consolidated primitive actually does and does not do. ;-) > > > > > I.e. I think the proposed changes are doing no harm, and the unavailability of a > > > generic primitive does not hinder future optimizations either in any significant > > > fashion. > > > > I will have a v3 with updated comments from Manfred. Thoughts on when/where > > to push this? > > Once everyone agrees I can apply it to the locking tree. I think PeterZ's was the > only objection? Oleg wasn't all that happy, either, but he did supply the relevant patch. > > The reason I ask is if this does not go in during this merge window, I need > > to fix the header comment on spin_unlock_wait(). > > Can try it next week after some testing - let's see how busy things get for Linus > in the merge window? Sounds good! Either way is fine with me. Thanx, Paul