Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757248Ab3IMBex (ORCPT ); Thu, 12 Sep 2013 21:34:53 -0400 Received: from longford.logfs.org ([213.229.74.203]:60277 "EHLO longford.logfs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751040Ab3IMBew (ORCPT ); Thu, 12 Sep 2013 21:34:52 -0400 Date: Thu, 12 Sep 2013 20:00:11 -0400 From: =?utf-8?B?SsO2cm4=?= Engel To: "Theodore Ts'o" Cc: John Stultz , Stephan Mueller , LKML , dave.taht@bufferbloat.net, Frederic Weisbecker , Thomas Gleixner Subject: Re: [PATCH] /dev/random: Insufficient of entropy on many architectures Message-ID: <20130913000011.GJ3809@logfs.org> References: <20130910203853.GG29237@thunk.org> <522F851D.1040101@linaro.org> <20130910211009.GI29237@thunk.org> <522F984C.2070909@linaro.org> <20130910223326.GD11063@thunk.org> <522FB9F1.3070905@linaro.org> <20130911005047.GA13315@thunk.org> <20130912210717.GC3809@logfs.org> <20130912233155.GB5279@thunk.org> <20130912233535.GI3809@logfs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20130912233535.GI3809@logfs.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1016 Lines: 24 On Thu, 12 September 2013 19:35:36 -0400, Jörn Engel wrote: > > I think the existing code is doing just fine for low interrupt loads. > It makes sense to spend a bit more work to squeeze the last bit of > randomness out. But when you get lots of interrupts, you can be > sloppy and just xor things into the pool. Btw, if we make collection cheap enough, we can start collecting entropy from the scheduler. Computers are fairly deterministic, but not that much. The exact time when calling schedule(), the kernel stack pointer and the userspace stack pointer all contain a bit of entropy. Particularly on machines that lack input and disk randomness I would expect some benefits from this. Jörn -- Audacity augments courage; hesitation, fear. -- Publilius Syrus -- 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/