From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 23 May 2002 17:37:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 23 May 2002 17:37:32 -0400 Received: from [195.39.17.254] ([195.39.17.254]:21915 "EHLO Elf.ucw.cz") by vger.kernel.org with ESMTP id ; Thu, 23 May 2002 17:37:29 -0400 Date: Wed, 22 May 2002 19:22:02 +0000 From: Pavel Machek To: Mark Gross Cc: Pavel Machek , "Vamsi Krishna S." , "Gross, Mark" , linux-kernel@vger.kernel.org, r1vamsi@in.ibm.com Subject: Re: PATCH Multithreaded core dumps for the 2.5.17 kernel was ....RE: PATCH Multithreaded core dump support for the 2.5.14 (and 15) kernel. Message-ID: <20020522192202.D229@toy.ucw.cz> In-Reply-To: <59885C5E3098D511AD690002A5072D3C057B489B@orsmsx111.jf.intel.com> <200205220748.g4M7mc2157646@northrelay01.pok.ibm.com> <20020522141747.G37@toy.ucw.cz> <200205222043.g4MKhsw06808@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Nice. This also closes another issue pointed out: freezing > > > a process while it is holding the mmap_sem, which may be needed later > > > while collecting thread registers on IA64. > > > > > > Now that Linus has accepted Pavel's swsusp, do you have any thoughts > > > on using Pavel's scheme to freeze processes? > > > > I attempt half of signal delivery to the threads, but that should not be > > a problem. Currently freezing stuff is there only for CONFIG_SWSUSP case, > > but it is probably small enough to be there unconditionaly. > > Pavel > > I think that although my tcore_suspend_threads and Pavel's freeze_processes > have similar results, I don't think using Pavel's approach for the core dump > is a good idea. > > 1) SMP is a stability problem. I want TCore to work for 2.4x kernels > soon. > 2) To avoid the issues with I/O bound threads waking up, Pavel's design waits > for the signal to get them running and then drops them in the "refrigerator". > > My design is explicitly going for the most accurate core dump it can. > If I need to wait for processes to wake up and get frozen on a large SMB box > then we can loose a lot of accuracy. Okay. > I do however; think Pavels work could benefit from using some of my approach. > It might simplify all those places where his patch tests p->state | > PK_FREEZE and then calls refrigerator. It perhaps make it work better for > SMP if software suspend is considered a usefull feature on a SMP systems. swsusp definitely is usable on SMP system. Take server with not-hotpluggable pci andpci card you want to add. How do you add it with minimum impact on users? suspend/add card/resume Pavel PS: I did not yet test swsusp on SMP, through. But I'd like it to work. -- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.