Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751262AbWCJAHn (ORCPT ); Thu, 9 Mar 2006 19:07:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752092AbWCJAHn (ORCPT ); Thu, 9 Mar 2006 19:07:43 -0500 Received: from mx.pathscale.com ([64.160.42.68]:22666 "EHLO mx.pathscale.com") by vger.kernel.org with ESMTP id S1751262AbWCJAHm (ORCPT ); Thu, 9 Mar 2006 19:07:42 -0500 Subject: Re: [PATCH 10 of 20] ipath - support for userspace apps using core driver From: "Bryan O'Sullivan" To: Roland Dreier Cc: rolandd@cisco.com, gregkh@suse.de, akpm@osdl.org, davem@davemloft.net, linux-kernel@vger.kernel.org, openib-general@openib.org In-Reply-To: References: <71644dd19420ddb07a75.1141922823@localhost.localdomain> <1141948516.10693.55.camel@serpentine.pathscale.com> Content-Type: text/plain Organization: PathScale, Inc. Date: Thu, 09 Mar 2006 16:07:42 -0800 Message-Id: <1141949262.10693.69.camel@serpentine.pathscale.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 919 Lines: 22 On Thu, 2006-03-09 at 16:01 -0800, Roland Dreier wrote: > Bryan> Any idea what I should be using instead? > > It depends what you're trying to do. Hence my original question: why > are you doing SetPageReserved? We're mapping some memory that the chip DMAs to into userspace, so that user processes can spin on memory locations without going through the kernel. The SetPageReserved hack is an attempt to stop the VM from reclaiming those pages from us once a user process exits. I realise that it's surely bogus, and I'd be thrilled to do something correct instead. We've tried doing both SetPageReserved and get_page, but it hasn't work out too well so far.