From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750800AbVJXOhl (ORCPT ); Mon, 24 Oct 2005 10:37:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750827AbVJXOhk (ORCPT ); Mon, 24 Oct 2005 10:37:40 -0400 Received: from omx3-ext.sgi.com ([192.48.171.20]:63176 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S1750800AbVJXOhk (ORCPT ); Mon, 24 Oct 2005 10:37:40 -0400 Date: Mon, 24 Oct 2005 07:37:15 -0700 From: Paul Jackson To: Andrew Morton Cc: Simon.Derr@bull.net, linux-kernel@vger.kernel.org, ak@suse.de, torvalds@osdl.org, clameter@sgi.com Subject: Re: [PATCH 01/02] cpuset bitmap and mask remap operators Message-Id: <20051024073715.02e1f3e3.pj@sgi.com> In-Reply-To: <20051024013713.25770d14.akpm@osdl.org> References: <20051024072744.10390.35722.sendpatchset@jackhammer.engr.sgi.com> <20051024004833.50d9676b.akpm@osdl.org> <20051024011613.691e28f4.pj@sgi.com> <20051024013713.25770d14.akpm@osdl.org> Organization: SGI X-Mailer: Sylpheed version 2.0.0beta5 (GTK+ 2.4.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew wrote: > hm. That hides what's really going on from the programmer. > > Oh well - you're the only guy who dinks with that stuff anyway ;) Halloween comes a week early to the Morton household. The patch from hell, circa April 2004, lives on to haunt Andrew . By the time we (wli, rusty, colpatch, ...) incorporated the following various constraints on these cpumask/nodemask macros, we were fortunate to only violate the "obvious to the programmer" constraint on the implementation internals: - near perfect code gen on small systems (1 word masks) - near perfect code gen on large systems (multiword masks) - type checking on arguments - keep the existing macro-style calling conventions: cpus_and(result, input1, input2) - a single bitmap internal implementation - the rest just wrappers - dramatic shinkage of kernel source devoted to this stuff - reduction in kernel text size across all architectures. Probably it is best that we not ask too many questions at this time ;). -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401