From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933439Ab2GEXVy (ORCPT ); Thu, 5 Jul 2012 19:21:54 -0400 Received: from li9-11.members.linode.com ([67.18.176.11]:37179 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933323Ab2GEXVx (ORCPT ); Thu, 5 Jul 2012 19:21:53 -0400 Date: Thu, 5 Jul 2012 19:21:36 -0400 From: "Theodore Ts'o" To: Matt Mackall Cc: Linus Torvalds , Linux Kernel Developers List , w@1wt.eu, ewust@umich.edu, zakir@umich.edu, greg@kroah.com, nadiah@cs.ucsd.edu, jhalderm@umich.edu, tglx@linutronix.de, davem@davemloft.net, stable@kernel.org Subject: Re: [PATCH 01/10] random: make 'add_interrupt_randomness()' do something sane Message-ID: <20120705232136.GD15685@thunk.org> Mail-Followup-To: Theodore Ts'o , Matt Mackall , Linus Torvalds , Linux Kernel Developers List , w@1wt.eu, ewust@umich.edu, zakir@umich.edu, greg@kroah.com, nadiah@cs.ucsd.edu, jhalderm@umich.edu, tglx@linutronix.de, davem@davemloft.net, stable@kernel.org References: <1341511933-11169-1-git-send-email-tytso@mit.edu> <1341511933-11169-2-git-send-email-tytso@mit.edu> <1341514078.4020.1213.camel@calx> <1341524367.4020.1324.camel@calx> <20120705220040.GA15685@thunk.org> <1341527482.4020.1355.camel@calx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1341527482.4020.1355.camel@calx> User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 05, 2012 at 05:31:22PM -0500, Matt Mackall wrote: > On systems with a timer interrupt and a sched_clock() that's > asynchronous to it, this actually loses a great source of entropy for > headless systems. Also: extra branch in fast path. > > It's better to mix and not credit than to not mix at all. Instead just > check the fast count against HZ before the credit. I'm not sure what you mean by this? - Ted