Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 10 Jul 2001 14:51:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 10 Jul 2001 14:50:56 -0400 Received: from weta.f00f.org ([203.167.249.89]:49794 "HELO weta.f00f.org") by vger.kernel.org with SMTP id ; Tue, 10 Jul 2001 14:50:49 -0400 Date: Wed, 11 Jul 2001 06:50:43 +1200 From: Chris Wedgwood To: "C. Slater" Cc: linux-kernel@vger.kernel.org Subject: Re: Switching Kernels without Rebooting? Message-ID: <20010711065043.G32421@weta.f00f.org> In-Reply-To: <000b01c10970$096cd8c0$fe00000a@cslater> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000b01c10970$096cd8c0$fe00000a@cslater> User-Agent: Mutt/1.3.18i X-No-Archive: Yes Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 10, 2001 at 02:42:12PM -0400, C. Slater wrote: Hi, i was just thinking about if it would be possible to switch kernels without haveing to restart the entire system. Pre-solaris 8 sun were promising this Sort of a "Live kernel replacement". It sort of goes along with the hot-swap-everything ideas. I was thinking something like - Take all the structs related to userspace memory and processes - Save them to a reserved area of memory - Halt the kernel, mostly what about timing critical things? you mention networking, but there are others - Wipe kernel-space memory clean to avoid confusion - Load new kernel into memory - Replace all saved structures what if the layout of these changes as it often does? - Start kernel running agin This seems like the easiest way to do it. The biggest problem is that there would be somewhere about 30 seconds where all processes would be frozen. It seems like difficult to implement solution for little gain. Linux can be booted _very_ quickly on modern machines, probably about 15s for most hardware. If you use burn linux into the rom of use a flashdisk (or similar solution), you can have everything rebooted in under five seconds. The zflinux chips/machines probably boot in half that, maybe less (as tested on a prototype many months ago). --cw - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/