Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 20 Sep 2002 12:35:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 20 Sep 2002 12:35:07 -0400 Received: from mx2.elte.hu ([157.181.151.9]:55207 "HELO mx2.elte.hu") by vger.kernel.org with SMTP id ; Fri, 20 Sep 2002 12:35:06 -0400 Date: Fri, 20 Sep 2002 18:47:41 +0200 (CEST) From: Ingo Molnar Reply-To: Ingo Molnar To: "Hanumanthu. H" Cc: linux-kernel@vger.kernel.org Subject: RE: [patch] generic-pidhash-2.5.36-D4, BK-curr In-Reply-To: Message-ID: 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: 1018 Lines: 29 On Fri, 20 Sep 2002, Hanumanthu. H wrote: > First of all, using bitmap is not that good as exposed in this > mailing list (I think some good guys at IBM already implememted > bitmap for pids as part of Linux scalability enhancements & [...] i mentioned that patch in earlier emails, and it is a whole different thing. The patch built a completely new bitmap *every* time we hit an already allocated PID, to find the next 'safe range'. The new PID allocator in 2.5.37 keeps one bitmap and does a single set-bit map operation in the fastpath and does a fast bitscan forward even in the worst case. > remember they discussed pros & cons too) & [...] (that approach was pretty gross i have to say.) > [...] atomic operations are not that cheap anyway. [...] huh? Ingo - 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/