From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758726AbZEMOZy (ORCPT ); Wed, 13 May 2009 10:25:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753781AbZEMOZp (ORCPT ); Wed, 13 May 2009 10:25:45 -0400 Received: from waste.org ([66.93.16.53]:44317 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753016AbZEMOZo (ORCPT ); Wed, 13 May 2009 10:25:44 -0400 Date: Wed, 13 May 2009 09:25:38 -0500 From: Matt Mackall To: Chris Peterson Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] [resend] drivers/net: remove network drivers' last few uses of IRQF_SAMPLE_RANDOM Message-ID: <20090513142535.GB31071@waste.org> References: <20090513060850.GZ31071@waste.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 13, 2009 at 12:17:29AM -0700, Chris Peterson wrote: > > The future model will continue to sample network > > devices on theory that they -might- be less than 100% observable and > > that can only increase our total (unmeasurable) amount of entropy. > > That sounds reasonable to me. So should all net drivers now specify > IRQF_SAMPLE_RANDOM? > > Or even simpler: could request_irq() assume IRQF_SAMPLE_RANDOM for any > interrupt that is not (say) IRQF_IRQPOLL or IRQF_PERCPU? Maybe. We don't want IRQ latency to suffer. So before we turn on sampling of -all- sources, we need to make sampling lighter weight and we need a way to say 'we have enough' so that we're not consuming CPU when our pools are 'full'. We could turn it on now and rely on the current trickle logic, but it's nice to have the water main off when doing significant plumbing. -- Mathematics is the supreme nostalgia of our time.