Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965150AbWBGQYB (ORCPT ); Tue, 7 Feb 2006 11:24:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965161AbWBGQYB (ORCPT ); Tue, 7 Feb 2006 11:24:01 -0500 Received: from odyssey.analogic.com ([204.178.40.5]:19205 "EHLO odyssey.analogic.com") by vger.kernel.org with ESMTP id S965150AbWBGQYA convert rfc822-to-8bit (ORCPT ); Tue, 7 Feb 2006 11:24:00 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 X-OriginalArrivalTime: 07 Feb 2006 16:23:56.0966 (UTC) FILETIME=[E4F81C60:01C62C02] Content-class: urn:content-classes:message Subject: pid_t range question Date: Tue, 7 Feb 2006 11:23:56 -0500 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: pid_t range question Thread-Index: AcYsAuUZjeee8OpmS9GDjn87SFsfTg== From: "linux-os \(Dick Johnson\)" To: "Linux kernel" Reply-To: "linux-os \(Dick Johnson\)" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1819 Lines: 37 On Linux, type pid_t is defined as an int if you look through all the intermediate definitions such as S32_T, etc. However, it wraps at 32767, the next value being 300. Does anybody know why it doesn't go to 0x7fffffff and then wrap to the first unused pid value? I know the code "reserves" the first 300 pids. That's not the question. I wonder why. Also I see the code setting the upper limit as well. I want to know why it is set within the range of a short and is not allowed to use the full range of an int. Nothing I see in the kernel, related to the pid, ever uses a short and no 'C' runtime interface limits this either! Also, attempts to change /proc/sys/kernel/pid_max fail if I attempt to increase it, but I can decrease it to where I don't have enough pids available to fork() the next command! Is this the correct behavior? Cheers, Dick Johnson Penguin : Linux version 2.6.13.4 on an i686 machine (5589.66 BogoMips). Warning : 98.36% of all statistics are fiction. _ **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. - 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/