Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268588AbUILKLe (ORCPT ); Sun, 12 Sep 2004 06:11:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268591AbUILKLc (ORCPT ); Sun, 12 Sep 2004 06:11:32 -0400 Received: from holomorphy.com ([207.189.100.168]:36484 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S268588AbUILKKv (ORCPT ); Sun, 12 Sep 2004 06:10:51 -0400 Date: Sun, 12 Sep 2004 03:10:49 -0700 From: William Lee Irwin III To: Anton Blanchard Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, viro@parcelfarce.linux.theplanet.co.uk Subject: Re: /proc/sys/kernel/pid_max issues Message-ID: <20040912101049.GM2660@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Anton Blanchard , linux-kernel@vger.kernel.org, mingo@elte.hu, viro@parcelfarce.linux.theplanet.co.uk References: <20040912085609.GK32755@krispykreme> <20040912093605.GJ2660@holomorphy.com> <20040912095805.GL2660@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040912095805.GL2660@holomorphy.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1123 Lines: 24 On Sun, Sep 12, 2004 at 02:36:05AM -0700, William Lee Irwin III wrote: >> + if (map > &pidmap_array[pid_max/BITS_PER_PAGE]) >> + map = pidmap_array; >> if (unlikely(!map->page)) { >> unsigned long page = get_zeroed_page(GFP_KERNEL); On Sun, Sep 12, 2004 at 02:58:05AM -0700, William Lee Irwin III wrote: > If pid_max == BITS_PER_PAGE*n, none of &pidmap_array[pid_max/BITS_PER_PAGE] > is usable, so if we must complete a full revolution around pidmap_array[] > to discover a free pid slightly less than last_pid we will miss it. Hence: That could only happen if max_steps were initialized to PIDMAP_ENTRIES instead of PIDMAP_ENTRIES + 1, so this more accurate upper bound is not strictly necessary, though with this in place, we could probably reduce max_steps to just PIDMAP_ENTRIES so we cycle no further than the block we began; I'll not bother with that. -- wli - 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/