Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753550Ab0H0H5r (ORCPT ); Fri, 27 Aug 2010 03:57:47 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:36932 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752385Ab0H0H5p convert rfc822-to-8bit (ORCPT ); Fri, 27 Aug 2010 03:57:45 -0400 Subject: Re: [PATCH] lglock: make lg_lock_global() actually lock globally From: Peter Zijlstra To: Nick Piggin Cc: Tejun Heo , Linus Torvalds , Jonathan Corbet , Rusty Russell , Al Viro , LKML In-Reply-To: <20100827055105.GA3857@amd> References: <20100825132815.108d8217@bike.lwn.net> <4C762BF9.5010305@kernel.org> <20100826094613.GA6411@amd> <4C7638B7.9060306@kernel.org> <1282817329.1975.486.camel@laptop> <20100826113858.GA6856@amd> <1282823139.1975.689.camel@laptop> <20100827055105.GA3857@amd> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Fri, 27 Aug 2010 09:57:36 +0200 Message-ID: <1282895856.1975.1711.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1169 Lines: 25 On Fri, 2010-08-27 at 15:51 +1000, Nick Piggin wrote: > > I don't see what is so nice about stop_machine()less cpu plug/unplug > or module unload. Module load definitely is nice because you can > have a lot of modules and on demand loading from non-privileged > operations. There's a large three lettered company that's promoting cpu hotplug use for power management, they hotplug at an astonishing rate. I've been saying hotplug isn't for that, and its a terrible slow path and disrupts your whole machine etc.. they don't seem to care much. The trouble seems to be that some smaller chips are now also wanting to use hotplug for PM because they want to safe silicon and not make their chips symmetric or crap like that... Its all really sad, and I'd prefer to keep hotplug slow and simple and simply never use it except when you like suspend your laptop -- but even there, people want auto-demand suspend crazy lot. -- 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/