From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751897Ab1HXXea (ORCPT ); Wed, 24 Aug 2011 19:34:30 -0400 Received: from mail-vx0-f174.google.com ([209.85.220.174]:58699 "EHLO mail-vx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803Ab1HXXe3 (ORCPT ); Wed, 24 Aug 2011 19:34:29 -0400 Date: Thu, 25 Aug 2011 01:34:24 +0200 From: Frederic Weisbecker To: "Paul E. McKenney" Cc: Andrew Morton , Josh Boyer , linux-kernel@vger.kernel.org Subject: Re: 3.0-git15 Atomic scheduling in pidmap_init Message-ID: <20110824233422.GD26417@somewhere.redhat.com> References: <20110817224916.GO2419@linux.vnet.ibm.com> <20110817230219.GJ2227@zod.bos.redhat.com> <20110817230641.GA7837@somewhere.redhat.com> <20110817231750.GK2227@zod.bos.redhat.com> <20110818183523.GD2325@linux.vnet.ibm.com> <20110818140034.668e8dea.akpm@linux-foundation.org> <20110818212334.GE2325@linux.vnet.ibm.com> <20110818215540.GA14098@linux.vnet.ibm.com> <20110824224454.GB26417@somewhere.redhat.com> <20110824231255.GZ2417@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110824231255.GZ2417@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 24, 2011 at 04:12:55PM -0700, Paul E. McKenney wrote: > Indeed, this was a bogus patch. The version I posted on the -rcu git > tree a few days ago has the correct "rdp->qs_pending = 0". I thought > that I had chased down all the bogus copies, but obviously not. :-( Ah ok. > > Should it perhaps set it to 1 only if we have rnp->gpnum > rnp->completed ? > > I would rather keep it simple. If rnp->gpnum > rnp->completed, then > the newly onlined CPU will notice and adjust appropriately soon enough. Ah, just to ensure I understood well is that because rcu_pending() (called from tick) would detect rnp->gpnum != rdp->gpnum and thus trigger the softirq that notes the new gpnum and toggles qs_pending? > Thanx, Paul > > > > rdp->passed_quiesc_completed = rnp->completed - 1; > > > } > > > raw_spin_unlock(&rnp->lock); /* irqs already disabled. */