From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH v2 0/9] Remove spin_unlock_wait() Date: Sat, 8 Jul 2017 04:41:12 -0700 Message-ID: <20170708114112.GO2393@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> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170708084323.iuyb4smp2a4ca4fh@gmail.com> Sender: linux-kernel-owner@vger.kernel.org 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" , torval List-Id: linux-arch.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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51138 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752726AbdGHLlT (ORCPT ); Sat, 8 Jul 2017 07:41:19 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v68BcXVE080076 for ; Sat, 8 Jul 2017 07:41:18 -0400 Received: from e17.ny.us.ibm.com (e17.ny.us.ibm.com [129.33.205.207]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bjufnmajh-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Sat, 08 Jul 2017 07:41:18 -0400 Received: from localhost by e17.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 8 Jul 2017 07:41:17 -0400 Date: Sat, 8 Jul 2017 04:41:12 -0700 From: "Paul E. McKenney" 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> Message-ID: <20170708114112.GO2393@linux.vnet.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: 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" Message-ID: <20170708114112.iX8jWzx0Mq70vQRfK8cp8Byz6BwKOXtJ9U6UA2mpP_s@z> 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