From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762725AbXFARIb (ORCPT ); Fri, 1 Jun 2007 13:08:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762378AbXFARII (ORCPT ); Fri, 1 Jun 2007 13:08:08 -0400 Received: from waste.org ([66.93.16.53]:60427 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762325AbXFARIH (ORCPT ); Fri, 1 Jun 2007 13:08:07 -0400 Date: Fri, 1 Jun 2007 12:07:40 -0500 From: Matt Mackall To: Mathieu Desnoyers Cc: Andi Kleen , akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [patch 2/9] Conditional Calls - Hash Table Message-ID: <20070601170739.GA11115@waste.org> References: <20070530140025.917261793@polymtl.ca> <20070530140227.398040643@polymtl.ca> <20070601160802.GL11166@waste.org> <20070601164623.GB4112@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070601164623.GB4112@Krystal> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 01, 2007 at 12:46:23PM -0400, Mathieu Desnoyers wrote: > * Matt Mackall (mpm@selenic.com) wrote: > > On Thu, May 31, 2007 at 03:42:50PM +0200, Andi Kleen wrote: > > > Mathieu Desnoyers writes: > > > > > > > Reimplementation of the cond calls which uses a hash table to hold the active > > > > cond_calls. It permits to first arm a cond_call and then load supplementary > > > > modules that contain this cond_call. > > > > > > Hash table is probably overkill. This is a very very slow path operation. > > > Can you simplify the code? Just a linked list of all the condcall segments > > > should be enough and then walk it. > > > > I think it could be greatly simplified by using symbols instead of > > strings. > > > > That is, doing cond_call(foo, func()) rather than cond_call("foo", > > func()). Here foo is a structure or type holding the relevant info to > > deal with the cond_call infrastructure. For unoptimized architectures, > > it can simply be a bool, which will be faster. > > > > This has the added advantage that the compiler will automatically pick > > up any misspellings of these things. And it saves the space we'd use > > on the hash table too. > > > > The idea is interesting, but does not fit the problem: AFAIK, it will > not be possible to do multiple declarations of the same symbol, which is > needed whenever we want to declare a cond_call() more than once or to > embed it in an inline function. It's not clear to me why either of those things are necessary. An example please? -- Mathematics is the supreme nostalgia of our time.