From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270681AbTG0GK1 (ORCPT ); Sun, 27 Jul 2003 02:10:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270685AbTG0GK0 (ORCPT ); Sun, 27 Jul 2003 02:10:26 -0400 Received: from mail1.kontent.de ([81.88.34.36]:53131 "EHLO Mail1.KONTENT.De") by vger.kernel.org with ESMTP id S270681AbTG0GKX (ORCPT ); Sun, 27 Jul 2003 02:10:23 -0400 From: Oliver Neukum To: Matthew Dharm , USB Developers , Kernel Developer List Subject: Re: [linux-usb-devel] System stalls using usb-storage Date: Sun, 27 Jul 2003 08:24:44 +0200 User-Agent: KMail/1.5.1 References: <20030723200051.C18354@one-eyed-alien.net> In-Reply-To: <20030723200051.C18354@one-eyed-alien.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200307270824.44851.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Donnerstag, 24. Juli 2003 05:00 schrieb Matthew Dharm: > Many people, including myself, have observed system stalls when using > usb-storage. It happens when copying large amounts of data to a USB device > -- everything (except the USB access) just stops for a little while. My > best guess is that the block cache is filling up (easy since USB is so > slow). Can you do a vmstat run? That should provide conclusive data. If so, write throteling is failing. > The question is, what is the best way to handle this. I'm guessing that > increasing the priority of the usb-storage control thread will help, but > that's just a guess. I'm not even sure how to go about doing that, tho... A kernel thread in the block io path has to have a higher priority than any user task. Otherwise a priority inversion is possible. Regards Oliver