From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267836AbUHEVre (ORCPT ); Thu, 5 Aug 2004 17:47:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267581AbUHEVqv (ORCPT ); Thu, 5 Aug 2004 17:46:51 -0400 Received: from omx2-ext.sgi.com ([192.48.171.19]:38299 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S267875AbUHEVp7 (ORCPT ); Thu, 5 Aug 2004 17:45:59 -0400 Date: Thu, 5 Aug 2004 14:45:29 -0700 From: Paul Jackson To: "Martin J. Bligh" Cc: akpm@osdl.org, hch@infradead.org, steiner@sgi.com, jbarnes@sgi.com, sylvain.jeaugey@bull.net, djh@sgi.com, linux-kernel@vger.kernel.org, colpatch@us.ibm.com, Simon.Derr@bull.net, ak@suse.de, lse-tech@lists.sourceforge.net, sivanich@sgi.com Subject: Re: [Lse-tech] [PATCH] new bitmap list format (for cpusets) Message-Id: <20040805144529.3d9c1fc2.pj@sgi.com> In-Reply-To: <250840000.1091738840@flay> References: <20040805100901.3740.99823.84118@sam.engr.sgi.com> <250840000.1091738840@flay> Organization: SGI X-Mailer: Sylpheed version 0.8.10claws (GTK+ 1.2.10; 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 Martin asks: > Can't we just do this up in userspace, ... Aha - I was expecting this question. Howdy. We could, I suppose (do this fancy bitmap formatting in userland). It's certainly been a pleasure to Simon Derr, Sylvain Jeaugey and myself, over the last six months, to be able to easily manipulate these big masks using classic Unix commands like cat and echo. The ability to atomically update a mask is unique to this interface. The existing bitmap_parse/bitmap_scnprintf interface only allows for a complete rewrite, not atomically adding or removing a node. However, I am not aware of a reason why we need the atomic update. Simon ... could you comment on this, and perhaps better motivate this new bitmap list format? -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.650.933.1373