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: Fri, 7 Jul 2017 07:41:07 -0700 Message-ID: <20170707144107.GA27202@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> 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: <20170707083128.wqk6msuuhtyykhpu@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 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? 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(). Thanx, Paul From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:32770 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750905AbdGGOlO (ORCPT ); Fri, 7 Jul 2017 10:41:14 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v67Ecq28130734 for ; Fri, 7 Jul 2017 10:41:13 -0400 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0b-001b2d01.pphosted.com with ESMTP id 2bjaqac9kk-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 07 Jul 2017 10:41:13 -0400 Received: from localhost by e11.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 7 Jul 2017 10:41:12 -0400 Date: Fri, 7 Jul 2017 07:41:07 -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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170707083128.wqk6msuuhtyykhpu@gmail.com> Message-ID: <20170707144107.GA27202@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: <20170707144107.nY9bmWcTfkQnBHowRO3Zrb3jsM5Jnr-JA8zi606g_aQ@z> 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? 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(). Thanx, Paul