From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752662AbWAHSDL (ORCPT ); Sun, 8 Jan 2006 13:03:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752664AbWAHSDL (ORCPT ); Sun, 8 Jan 2006 13:03:11 -0500 Received: from mail.tv-sign.ru ([213.234.233.51]:31460 "EHLO several.ru") by vger.kernel.org with ESMTP id S1752662AbWAHSDJ (ORCPT ); Sun, 8 Jan 2006 13:03:09 -0500 Message-ID: <43C165BC.F7C6DCF5@tv-sign.ru> Date: Sun, 08 Jan 2006 22:19:24 +0300 From: Oleg Nesterov X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.2.20 i686) X-Accept-Language: en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Cc: Dipankar Sarma , Manfred Spraul , Linus Torvalds , "Paul E. McKenney" , Andrew Morton Subject: [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending() Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org ->donelist becomes != NULL only in rcu_process_callbacks(). rcu_process_callbacks() always calls rcu_do_batch() when ->donelist != NULL. rcu_do_batch() schedules rcu_process_callbacks() again if ->donelist was not flushed entirely. So ->donelist != NULL means that rcu_tasklet is either TASKLET_STATE_SCHED or TASKLET_STATE_RUN, we don't need to check it in __rcu_pending(). [ This patch was tested with rcutorture.ko, I don't understand it's output, but it says "End of test: SUCCESS". So if this patch incorrect blame Paul, not me! ] Signed-off-by: Oleg Nesterov --- 2.6.15/kernel/rcupdate.c~2_DONE 2006-01-08 21:35:21.000000000 +0300 +++ 2.6.15/kernel/rcupdate.c 2006-01-08 21:55:45.000000000 +0300 @@ -454,10 +454,6 @@ static int __rcu_pending(struct rcu_ctrl if (!rdp->curlist && rdp->nxtlist) return 1; - /* This cpu has finished callbacks to invoke */ - if (rdp->donelist) - return 1; - /* The rcu core waits for a quiescent state from the cpu */ if (rdp->quiescbatch != rcp->cur || rdp->qs_pending) return 1;