Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932940AbXAaKTZ (ORCPT ); Wed, 31 Jan 2007 05:19:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932942AbXAaKTZ (ORCPT ); Wed, 31 Jan 2007 05:19:25 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:39310 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932940AbXAaKTY (ORCPT ); Wed, 31 Jan 2007 05:19:24 -0500 Date: Wed, 31 Jan 2007 11:17:10 +0100 From: Ingo Molnar To: Daniel Walker Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, johnstul@us.ibm.com, Thomas Gleixner Subject: Re: [PATCH 09/23] clocksource: add block notifier Message-ID: <20070131101710.GB22377@elte.hu> References: <20070131033710.420168478@mvista.com> <20070131033805.815147778@mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070131033805.815147778@mvista.com> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.8 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.8 required=5.9 tests=ALL_TRUSTED,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4806] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 38 * Daniel Walker wrote: > Adds a call back interface for register/rating change events. This is > also used later in this series to signal other interesting events. This patch adds: > +#define CLOCKSOURCE_NOTIFY_REGISTER 1 > +#define CLOCKSOURCE_NOTIFY_RATING 2 > +#define CLOCKSOURCE_NOTIFY_FREQ 4 and a later patch adds: > +#define CLOCKSOURCE_NOTIFY_UNSTABLE 8 while i tentatively agree with the introduction of clocksource driver notifications in general (given any actual real users of that infrastructure), i can see three problems with your notifier changes: firstly, with the full changes applied, CLOCKSOURCE_NOTIFY_RATING is totally unused (and not even driven by the core clocksource code). secondly, CLOCKSOURCE_NOTIFY_REGISTER is only used by the core clocksource code and no register-notifier interface is exposed: this makes the whole thing an expensive NOP. thirdly, CLOCKSOURCE_NOTIFY_FREQ is totally unused as well. (there are tons of examples in the kernel of how to do driver notification APIs properly.) Ingo - 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/