From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266391AbUGBCzX (ORCPT ); Thu, 1 Jul 2004 22:55:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266409AbUGBCzW (ORCPT ); Thu, 1 Jul 2004 22:55:22 -0400 Received: from smtp800.mail.sc5.yahoo.com ([66.163.168.179]:20383 "HELO smtp800.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S266391AbUGBCzH (ORCPT ); Thu, 1 Jul 2004 22:55:07 -0400 From: Kevin Corry To: Andrew Morton Subject: Re: [PATCH] 1/1: Device-Mapper: Remove 1024 devices limitation Date: Thu, 1 Jul 2004 21:54:16 -0500 User-Agent: KMail/1.5.4 Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org References: <200407011035.13283.kevcorry@us.ibm.com> <20040701143857.256959e5.akpm@osdl.org> In-Reply-To: <20040701143857.256959e5.akpm@osdl.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200407012154.16312.kevcorry@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 01 July 2004 16:38, Andrew Morton wrote: > Kevin Corry wrote: > > Remove the limitation of 1024 DM devices. > > That seems to be an awful lot of fuss just to maintain a bitmap. Mmm...perhaps. > What is a realistic useful upper bound on the minors? Would it not be > sufficient to increase the size of the statically allocated bitmap? I guess that depends on who you ask. Obviously, for most people the previous limit of 1024 devices is more than enough. But there's always going to be folks pushing the limits. So I figured I'd go ahead and rewrite it to theoretically allow for the maximum range of minor numbers, while trying not to waste memory for the common case. > Did you consider going to a different data structure altogether? > lib/radix-tree.c and lib/idr.c provide appropriate ones. The idr stuff looks promising at first glance. I'll take a better look at it tomorrow and see if we can switch from a bit-set to one of these data structures. -- Kevin Corry kevcorry@us.ibm.com http://evms.sourceforge.net