Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261563AbUAUEBz (ORCPT ); Tue, 20 Jan 2004 23:01:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261606AbUAUEBy (ORCPT ); Tue, 20 Jan 2004 23:01:54 -0500 Received: from e1.ny.us.ibm.com ([32.97.182.101]:52688 "EHLO e1.ny.us.ibm.com") by vger.kernel.org with ESMTP id S261563AbUAUEBx (ORCPT ); Tue, 20 Jan 2004 23:01:53 -0500 Date: Wed, 21 Jan 2004 09:36:33 +0530 From: Srivatsa Vaddagiri To: Tim Hockin Cc: Nick Piggin , Rusty Russell , linux-kernel@vger.kernel.org, torvalds@osdl.org, akpm@osdl.org, rml@tech9.net Subject: Re: CPU Hotplug: Hotplug Script And SIGPWR Message-ID: <20040121093633.A3169@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <400CCE2F.2060502@cyberone.com.au> <20040120065207.GA10993@hockin.org> <400CD4B5.6020507@cyberone.com.au> <20040120073032.GB12638@hockin.org> <400CDCA1.5070200@cyberone.com.au> <20040120075409.GA13897@hockin.org> <400CE354.8060300@cyberone.com.au> <20040120082943.GA15733@hockin.org> <400CE8DC.70307@cyberone.com.au> <20040120084352.GD15733@hockin.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20040120084352.GD15733@hockin.org>; from thockin@hockin.org on Tue, Jan 20, 2004 at 12:43:52AM -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1262 Lines: 31 On Tue, Jan 20, 2004 at 12:43:52AM -0800, Tim Hockin wrote: > IFF the app is designed to handle it. The existence of a SIGPWR handler > does not necessarily imply that, though. a SIGCPU or something might > correlate 1:1 with this, but SIGPWR doesn't. I agree we should have a separe signal for CPU Hotplug. By default the signal will be ignored, unless a task registers a signal handler for that special signal. That way, tasks which "knowingly" change their CPU affinity will be able to tackle a CPU going down by handling the signal (probably change their CPU affinity again), while tasks which have their CPU affinity changed "unknowingly" (by other tasks) will just ignore the signal. The hotplug script interface allows the admin to go and change the CPU affinity again for the second class of tasks, if needed. The only problem with a new signal is conformance to standards (if any). -- Thanks and Regards, Srivatsa Vaddagiri, Linux Technology Center, IBM Software Labs, Bangalore, INDIA - 560017 - 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/