Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 18 Mar 2003 13:59:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 18 Mar 2003 13:59:05 -0500 Received: from pixar.pixar.com ([138.72.10.20]:18154 "EHLO pixar.pixar.com") by vger.kernel.org with ESMTP id ; Tue, 18 Mar 2003 13:59:04 -0500 Date: Tue, 18 Mar 2003 11:09:55 -0800 From: Lars Damerow To: linux-kernel@vger.kernel.org Subject: Problem: high CPU usage during unmount Message-ID: <20030318190955.GC4094@pixar.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1416 Lines: 36 Hello, folks! In all kernel versions I've tried, including 2.4.20, I'm seeing very high CPU usage (typically 99%) while my system unmounts a large number of mounts. All of this CPU time appears to be used by the kernel's umount() call. The slowdown seriously affects the system's interactivity, and its duration depends on the number of umounts the system has to do. For 79 mounts, it lasts about 16.5 seconds. I wrote a shell script that calls umount for each of these 79 mounts in a for loop, and running it through time shows it to take 15.6 seconds of system time with 95% CPU consumed. While this typically happens through amd-managed NFS mounts, I've found that it also happens with loopback mounts. Does this sound familiar to anyone, and if so, is there anything I can do to stop it? I can produce more debugging information if that would be useful. Please CC me on any responses. Thanks very much for your time! -lars ___________________________________________________________ lars damerow button pusher pixar animation studios lars@pixar.com I want to raise my freak flag higher and higher and I want to raise my freak flag and never be alone... -tmbg - 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/