From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965380AbXBQXrt (ORCPT ); Sat, 17 Feb 2007 18:47:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965388AbXBQXrs (ORCPT ); Sat, 17 Feb 2007 18:47:48 -0500 Received: from mail.screens.ru ([213.234.233.54]:49597 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965380AbXBQXrs (ORCPT ); Sat, 17 Feb 2007 18:47:48 -0500 Date: Sun, 18 Feb 2007 02:47:28 +0300 From: Oleg Nesterov To: "Rafael J. Wysocki" Cc: ego@in.ibm.com, akpm@osdl.org, paulmck@us.ibm.com, mingo@elte.hu, vatsa@in.ibm.com, dipankar@in.ibm.com, venkatesh.pallipadi@intel.com, linux-kernel@vger.kernel.org, Pavel Machek Subject: Re: [RFC PATCH(Experimental) 0/4] Freezer based Cpu-hotplug Message-ID: <20070217234728.GA679@tv-sign.ru> References: <20070214144031.GA15257@in.ibm.com> <200702171224.46626.rjw@sisk.pl> <20070217213406.GA541@tv-sign.ru> <200702172324.44892.rjw@sisk.pl> <20070217234201.GA591@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070217234201.GA591@tv-sign.ru> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 02/18, Oleg Nesterov wrote: > > On 02/17, Rafael J. Wysocki wrote: > > > > Alternatively, we can move the check into refrigerator(), like this: > > > > --- linux-2.6.20-git13.orig/kernel/power/process.c > > +++ linux-2.6.20-git13/kernel/power/process.c > > @@ -39,6 +39,11 @@ void refrigerator(void) > > /* Hmm, should we be allowed to suspend when there are realtime > > processes around? */ > > long save; > > + > > + /* Freeze the task unless there is a vfork completion pending */ > > + if (current->vfork_done) > > + return; > > + > > This means that "current" returns to user space (get_signal_to_deliver > will clear TIF_SIGPENDING) and runs. While try_to_freeze_tasks() thinks > it is frozen. Ah, sorry. I am wrong, current has no PF_FROZEN yet. However, this means that sys_vfork() makes impossible to freeze processes until child exits/execs. Not good. Oleg.