From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 27 May 2002 11:07:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 27 May 2002 11:07:03 -0400 Received: from zeus.cs.um.edu.mt ([193.188.34.114]:64401 "EHLO zeus.cs.um.edu.mt") by vger.kernel.org with ESMTP id ; Mon, 27 May 2002 11:07:03 -0400 Message-ID: <3CF2A0FB.8090507@um.edu.mt> Date: Mon, 27 May 2002 17:11:23 -0400 From: Joseph Cordina Organization: University of Malta User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20011126 Netscape6/6.2.1 X-Accept-Language: en-us MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: wait queue process state Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I am quite new to this list and thus does not know if this question has been answered many a times. I have looked in the archive but could not find it. Here goes anyway: I realised that when processes are placed in the wait queue, they are set at either INTERRUPTIBLE or NONINTERRUPTIBLE. I also noticed that something like file access is set as NONINTERRUPTIBLE. Could someone please tell me the reason for having these two states. I can understand that INTERRUPTIBLE can be made to be interrupted by a timer or a signal and vice versa for UNTERRUPTIBLE. Yet what makes blocking system calls as INTERRUPTIBLE or NONINTERRUPTIBLE. Also why is file access considered as NONINTERRUPTIBLE. In addition, inside the kernel running, are these two different states treated differently (apart from the allowance to be interrupted or otherwise). The reason I am asking is that I am working on scheduler activations which allow new kernel threads to be created when a kernel thread blocks inside the kernel. Yet this only works for INTERRUPTIBLE processes, I was thinking of making it work also for NONINTERRUPTIBLE processes. Just wondering if this would have any repurcusions. Also when a process generates a page fault which causes a page to be retreived from the filesystem, it such a process placed in the wait queue as NONINTERRUPTIBLE also ? Cheers Joseph Cordina University of Malta