Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751294AbVKIIhH (ORCPT ); Wed, 9 Nov 2005 03:37:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751315AbVKIIhH (ORCPT ); Wed, 9 Nov 2005 03:37:07 -0500 Received: from gateway.argo.co.il ([194.90.79.130]:6667 "EHLO argo2k.argo.co.il") by vger.kernel.org with ESMTP id S1751294AbVKIIhF (ORCPT ); Wed, 9 Nov 2005 03:37:05 -0500 Message-ID: <4371B52E.4030004@argo.co.il> Date: Wed, 09 Nov 2005 10:37:02 +0200 From: Avi Kivity User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Oliver Neukum CC: Jeff Garzik , Linux Kernel , Jens Axboe Subject: Re: userspace block driver? References: <4371A4ED.9020800@pobox.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 09 Nov 2005 08:37:03.0863 (UTC) FILETIME=[C2AE5070:01C5E508] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1077 Lines: 31 Oliver Neukum wrote: >On Wed, 9 Nov 2005, Jeff Garzik wrote: > > > >>Has anybody put any thought towards how a userspace block driver would work? >> >>Consider a block device implemented via an SSL network connection. I don't >>want to put SSL in the kernel, which means the only other alternative is to >>pass data to/from a userspace daemon. >> >> > >I am afraid this is impossible without some heavy infrastructure work. >You will almost inevitably deadlock. Yes, you can mlock() your driver, but >that still will not tell the kernel that GFP_KERNEL must be replaced with >GFP_NOIO if it is triggered by syscalls you are doing. > > > A simple patch can help here (in addition to mlockall()): http://www.ussg.iu.edu/hypermail/linux/kernel/0407.3/0297.html you might want to increase the free memory target as well. - 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/