From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751526AbWAINmt (ORCPT ); Mon, 9 Jan 2006 08:42:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751532AbWAINmt (ORCPT ); Mon, 9 Jan 2006 08:42:49 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:22735 "EHLO e36.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751526AbWAINms (ORCPT ); Mon, 9 Jan 2006 08:42:48 -0500 Date: Mon, 9 Jan 2006 19:12:39 +0530 From: Srivatsa Vaddagiri To: Oleg Nesterov Cc: linux-kernel@vger.kernel.org, Dipankar Sarma , Manfred Spraul , Linus Torvalds , "Paul E. McKenney" , Andrew Morton Subject: Re: [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending() Message-ID: <20060109134238.GA26700@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <43C165BC.F7C6DCF5@tv-sign.ru> <20060109093141.GA10811@in.ibm.com> <43C2785C.4E937748@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43C2785C.4E937748@tv-sign.ru> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 09, 2006 at 05:51:08PM +0300, Oleg Nesterov wrote: > Srivatsa Vaddagiri wrote: > > If we have to do a rcu_move_batch of ->donelist also, > > then perhaps the ->donelist != NULL check is required in > > rcu_pending? > > rcu_move_batch() always adds entries to the ->nxttail, so I think > this patch is correct. Hmm ..adding entries on dead cpu's ->donelist to ->nxtlist of some other CPU doesnt make sense (it re-triggers graceperiods for all those callbacks which is not needed). Maybe rcu_move_batch should take that into account and instead add to ->donelist of current CPU which is processing the CPU_DEAD callback. In which case, ->donelist != NULL check is still reqd in rcu_pending ? -- Thanks and Regards, Srivatsa Vaddagiri, Linux Technology Center, IBM Software Labs, Bangalore, INDIA - 560017