Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424745AbWKPWW0 (ORCPT ); Thu, 16 Nov 2006 17:22:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1424749AbWKPWW0 (ORCPT ); Thu, 16 Nov 2006 17:22:26 -0500 Received: from smtp.osdl.org ([65.172.181.4]:61143 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1424747AbWKPWWY (ORCPT ); Thu, 16 Nov 2006 17:22:24 -0500 Date: Thu, 16 Nov 2006 14:21:57 -0800 (PST) From: Linus Torvalds To: Alan Stern cc: Thomas Gleixner , Ingo Molnar , LKML , john stultz , David Miller , Arjan van de Ven , Andrew Morton , Andi Kleen , "Paul E. McKenney" Subject: Re: [patch] cpufreq: mark cpufreq_tsc() as core_initcall_sync In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1551 Lines: 37 On Thu, 16 Nov 2006, Alan Stern wrote: > On Thu, 16 Nov 2006, Linus Torvalds wrote: > > > > Paul, it would be _really_ nice to have some way to just initialize > > that SRCU thing statically. This kind of crud is just crazy. > > I looked into this back when SRCU was first added. It's essentially > impossible to do it, because the per-cpu memory allocation & usage APIs > are completely different for the static and the dynamic cases. I don't think that's how you'd want to do it. There's no way to do an initialization of a percpu allocation statically. That's pretty obvious. What I'd suggest instead, is to make the allocation dynamic, and make it inside the srcu functions (kind of like I did now, but I did it at a higher level). Doing it at the high level was trivial right now, but we may well end up hitting this problem again if people start using SRCU more. Right now I suspect the cpufreq notifier is the only thing that uses SRCU, and it already showed this problem with SRCU initializers. So I was more thinking about moving my "one special case high level hack" down lower, down to the SRCU level, so that we'll never see _more_ of those horrible hacks. We'll still have the hacky thing, but at least it will be limited to a single place - the SRCU code itself. Linus - 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/