From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752523Ab3CBREF (ORCPT ); Sat, 2 Mar 2013 12:04:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44013 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752275Ab3CBRED (ORCPT ); Sat, 2 Mar 2013 12:04:03 -0500 Date: Sat, 2 Mar 2013 18:01:45 +0100 From: Oleg Nesterov To: Lai Jiangshan Cc: paulmck@linux.vnet.ibm.com, "Srivatsa S. Bhat" , Lai Jiangshan , Michel Lespinasse , linux-doc@vger.kernel.org, peterz@infradead.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, namhyung@kernel.org, mingo@kernel.org, linux-arch@vger.kernel.org, linux@arm.linux.org.uk, xiaoguangrong@linux.vnet.ibm.com, wangyun@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, rusty@rustcorp.com.au, rostedt@goodmis.org, rjw@sisk.pl, vincent.guittot@linaro.org, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, sbw@mit.edu, tj@kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] lglock: add read-preference local-global rwlock Message-ID: <20130302170145.GA29769@redhat.com> References: <512C7A38.8060906@linux.vnet.ibm.com> <512CC509.1050000@linux.vnet.ibm.com> <512D0D67.9010609@linux.vnet.ibm.com> <512E7879.20109@linux.vnet.ibm.com> <5130E8E2.50206@cn.fujitsu.com> <20130301182854.GA3631@redhat.com> <513201B7.5070004@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <513201B7.5070004@cn.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/02, Lai Jiangshan wrote: > > On 02/03/13 02:28, Oleg Nesterov wrote: > > Lai, I didn't read this discussion except the code posted by Michel. > > I'll try to read this patch carefully later, but I'd like to ask > > a couple of questions. > > > > This version looks more complex than Michel's, why? Just curious, I > > am trying to understand what I missed. See > > http://marc.info/?l=linux-kernel&m=136196350213593 > > Michel changed my old draft version a little, his version is good enough for me. Yes, I see. But imho Michel suggested the valuable cleanup, the code becomes even more simple with the same perfomance. Your v2 looks almost correct to me, but I still think it makes sense to incorporate the simplification from Michel. > My new version tries to add a little better nestable support with only > adding single __this_cpu_op() in _read_[un]lock(). How? Afaics with or without FALLBACK_BASE you need _reed + _inc/dec in _read_lock/unlock. Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by ozlabs.org (Postfix) with ESMTP id ABA972C02F6 for ; Sun, 3 Mar 2013 04:03:57 +1100 (EST) Date: Sat, 2 Mar 2013 18:01:45 +0100 From: Oleg Nesterov To: Lai Jiangshan Subject: Re: [PATCH] lglock: add read-preference local-global rwlock Message-ID: <20130302170145.GA29769@redhat.com> References: <512C7A38.8060906@linux.vnet.ibm.com> <512CC509.1050000@linux.vnet.ibm.com> <512D0D67.9010609@linux.vnet.ibm.com> <512E7879.20109@linux.vnet.ibm.com> <5130E8E2.50206@cn.fujitsu.com> <20130301182854.GA3631@redhat.com> <513201B7.5070004@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <513201B7.5070004@cn.fujitsu.com> Cc: Lai Jiangshan , linux-doc@vger.kernel.org, peterz@infradead.org, fweisbec@gmail.com, Michel Lespinasse , mingo@kernel.org, linux-arch@vger.kernel.org, linux@arm.linux.org.uk, xiaoguangrong@linux.vnet.ibm.com, wangyun@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, rusty@rustcorp.com.au, rostedt@goodmis.org, rjw@sisk.pl, namhyung@kernel.org, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, vincent.guittot@linaro.org, sbw@mit.edu, "Srivatsa S. Bhat" , tj@kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 03/02, Lai Jiangshan wrote: > > On 02/03/13 02:28, Oleg Nesterov wrote: > > Lai, I didn't read this discussion except the code posted by Michel. > > I'll try to read this patch carefully later, but I'd like to ask > > a couple of questions. > > > > This version looks more complex than Michel's, why? Just curious, I > > am trying to understand what I missed. See > > http://marc.info/?l=linux-kernel&m=136196350213593 > > Michel changed my old draft version a little, his version is good enough for me. Yes, I see. But imho Michel suggested the valuable cleanup, the code becomes even more simple with the same perfomance. Your v2 looks almost correct to me, but I still think it makes sense to incorporate the simplification from Michel. > My new version tries to add a little better nestable support with only > adding single __this_cpu_op() in _read_[un]lock(). How? Afaics with or without FALLBACK_BASE you need _reed + _inc/dec in _read_lock/unlock. Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 From: oleg@redhat.com (Oleg Nesterov) Date: Sat, 2 Mar 2013 18:01:45 +0100 Subject: [PATCH] lglock: add read-preference local-global rwlock In-Reply-To: <513201B7.5070004@cn.fujitsu.com> References: <512C7A38.8060906@linux.vnet.ibm.com> <512CC509.1050000@linux.vnet.ibm.com> <512D0D67.9010609@linux.vnet.ibm.com> <512E7879.20109@linux.vnet.ibm.com> <5130E8E2.50206@cn.fujitsu.com> <20130301182854.GA3631@redhat.com> <513201B7.5070004@cn.fujitsu.com> Message-ID: <20130302170145.GA29769@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/02, Lai Jiangshan wrote: > > On 02/03/13 02:28, Oleg Nesterov wrote: > > Lai, I didn't read this discussion except the code posted by Michel. > > I'll try to read this patch carefully later, but I'd like to ask > > a couple of questions. > > > > This version looks more complex than Michel's, why? Just curious, I > > am trying to understand what I missed. See > > http://marc.info/?l=linux-kernel&m=136196350213593 > > Michel changed my old draft version a little, his version is good enough for me. Yes, I see. But imho Michel suggested the valuable cleanup, the code becomes even more simple with the same perfomance. Your v2 looks almost correct to me, but I still think it makes sense to incorporate the simplification from Michel. > My new version tries to add a little better nestable support with only > adding single __this_cpu_op() in _read_[un]lock(). How? Afaics with or without FALLBACK_BASE you need _reed + _inc/dec in _read_lock/unlock. Oleg.