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: Thu, 6 Jul 2017 09:20:24 -0700 Message-ID: <20170706162024.GD2393@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> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: 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" Return-path: Content-Disposition: inline In-Reply-To: <20170706160555.xc63yydk77gmttae@hirez.programming.kicks-ass.net> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On Thu, Jul 06, 2017 at 06:05:55PM +0200, Peter Zijlstra wrote: > On Thu, Jul 06, 2017 at 02:12:24PM +0000, David Laight wrote: > > From: Paul E. McKenney [ . . . ] > Now on the one hand I feel like Oleg that it would be a shame to loose > the optimization, OTOH this thing is really really tricky to use, > and has lead to a number of bugs already. I do agree, it is a bit sad to see these optimizations go. So, should this make mainline, I will be tagging the commits that spin_unlock_wait() so that they can be easily reverted should someone come up with good semantics and a compelling use case with compelling performance benefits. Thanx, Paul