From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763944AbZDHJxL (ORCPT ); Wed, 8 Apr 2009 05:53:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758967AbZDHJwz (ORCPT ); Wed, 8 Apr 2009 05:52:55 -0400 Received: from casper.infradead.org ([85.118.1.10]:41144 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758868AbZDHJwy (ORCPT ); Wed, 8 Apr 2009 05:52:54 -0400 Subject: Re: [PATCH]kernel/sched_fair.c: task_new_fair() have call update_curr() twice From: Peter Zijlstra To: "figo.zhang" Cc: mingo@elte.hu, linux-kernel@vger.kernel.org In-Reply-To: <20090408021038.2D1A4F50054@mail.kolorific.com> References: <20090408021038.2D1A4F50054@mail.kolorific.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Wed, 08 Apr 2009 11:54:41 +0200 Message-Id: <1239184481.24828.1374.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2009-04-08 at 10:10 +0800, figo.zhang wrote: > The task_new_fair() will call update_curr() twice, one is in > task_new_fair(), and other one in > enqueue_task_fair()->enqueue_entity(), they do the same, so it > should be need one time. > > Signed-off-by: figo.zhang > > > diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c > index 3816f21..d5913bb 100644 > --- a/kernel/sched_fair.c > +++ b/kernel/sched_fair.c > @@ -1713,7 +1713,7 @@ static void task_new_fair(struct rq *rq, struct > task_struct *p) > sched_info_queued(p); > > - update_curr(cfs_rq); > + > place_entity(cfs_rq, se, 1); > > /* 'curr' will be NULL if the child belongs to a different > group */ Except that update_curr() changes ->vruntime, and place_entity() uses ->vruntime. Therefore the above is not a NOP.