Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261873AbTKGWSR (ORCPT ); Fri, 7 Nov 2003 17:18:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261872AbTKGWSB (ORCPT ); Fri, 7 Nov 2003 17:18:01 -0500 Received: from 216-239-45-4.google.com ([216.239.45.4]:18205 "EHLO 216-239-45-4.google.com") by vger.kernel.org with ESMTP id S264102AbTKGMEc (ORCPT ); Fri, 7 Nov 2003 07:04:32 -0500 Date: Fri, 7 Nov 2003 04:04:27 -0800 From: Frank Cusack To: lkml Subject: preemption when running in the kernel Message-ID: <20031107040427.A32421@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 754 Lines: 19 (2.4 kernel) When a process is running in the kernel, can it be pre-empted at any time? (Unless you explicity disable preemption.) I think not, because wouldn't it be unsafe to grab a spinlock? Or does grabbing a spinlock disable preemption. I mean spin_lock(), not spin_lock_irqsave(). Secondly, can multiple processes be in the kernel at the same time? I think so, that's the reason for the fine grained locks instead of the BKL. Or do fine grained locks only serve to allow preemption. thanks! /fc - 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/