Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161105AbXECIBv (ORCPT ); Thu, 3 May 2007 04:01:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161495AbXECIBv (ORCPT ); Thu, 3 May 2007 04:01:51 -0400 Received: from caramon.arm.linux.org.uk ([217.147.92.249]:2897 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161105AbXECIBu (ORCPT ); Thu, 3 May 2007 04:01:50 -0400 Date: Thu, 3 May 2007 09:01:42 +0100 From: Russell King To: Glen Turner Cc: Linux kernel Subject: Re: Detecting process death for anycast named process monitoring Message-ID: <20070503080142.GB12018@flint.arm.linux.org.uk> Mail-Followup-To: Glen Turner , Linux kernel References: <4638FCEA.4010806@gdt.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4638FCEA.4010806@gdt.id.au> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1573 Lines: 40 On Thu, May 03, 2007 at 06:34:42AM +0930, Glen Turner wrote: > We don't want to be the parent of the running process, because that > doesn't add robustness. If the parent process dies, then the service > dies, and the interface still stays up. Okay. > We don't want to poll, because that isn't pretty and the polling > interval needs to be very short on a big ISP's DNS servers. If you did have a process which polls for the service, what happens if that process dies? > I have tried using the various notify functions against /proc, but > they don't work for that filesystem. I have tried using notify > against a UNIX domain socket, but notify doesn't work for > that either. > > Suggestions, or a patch to support notify for /proc or to push > process death notifications into DBUS or whatever, are welcome. What if the dbus system dies? What if your monitoring process dies? Surely a simple solution is going to be the best solution? Given that you're always going to have another process (which might be killed) your thought about having a parent process monitor the death of the child seems to be the simplest. You could also have that process interact with a watchog, so failures with that process cause a reboot. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - 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/