From owner-svn-src-all@FreeBSD.ORG Wed Nov 4 14:43:21 2009 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 820F3106566B; Wed, 4 Nov 2009 14:43:21 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (skuns.zoral.com.ua [91.193.166.194]) by mx1.freebsd.org (Postfix) with ESMTP id AC0808FC1D; Wed, 4 Nov 2009 14:43:20 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id nA4EhFBE034497 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 4 Nov 2009 16:43:15 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3) with ESMTP id nA4EhFtc039704; Wed, 4 Nov 2009 16:43:15 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3/Submit) id nA4EhFfs039703; Wed, 4 Nov 2009 16:43:15 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Wed, 4 Nov 2009 16:43:15 +0200 From: Kostik Belousov To: Attilio Rao Message-ID: <20091104144315.GH2331@deviant.kiev.zoral.com.ua> References: <200911040132.nA41WxtQ012750@svn.freebsd.org> <20091104055811.GY1293@hoeg.nl> <3bbf2fe10911040449j5938ca7eqca5829ceced66f48@mail.gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="54u2kuW9sGWg/X+X" Content-Disposition: inline In-Reply-To: <3bbf2fe10911040449j5938ca7eqca5829ceced66f48@mail.gmail.com> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: svn-src-head@freebsd.org, Ed Schouten , svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r198868 - in head/sys: amd64/amd64 i386/i386 X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Nov 2009 14:43:21 -0000 --54u2kuW9sGWg/X+X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Nov 04, 2009 at 01:49:41PM +0100, Attilio Rao wrote: > 2009/11/4 Ed Schouten : > > Hi Attilio, > > > > * Attilio Rao wrote: > >> Opteron rev E family of processor expose a bug where, in very rare > >> ocassions, memory barriers semantic is not honoured by the hardware > >> itself. As a result, some random breakage can happen in uninvestigable > >> ways (for further explanation see at the content of the commit itself). > > > > Ooh. Sounds like an interesting bug. > > > > The bug doesn't manifest itself on UP, right? If so, maybe we should add > > some very short instructions to the warning on how to disable SMP. >=20 > Due to the semantic of the bug, I think that it can manifest itself on > UP and a memory barrier failing on UP means that PREEMPTION can blow > up. Considering this I wouldn't suggest anything different between the > UP vs SMP case. CPU is always self-consistent, isn't it ? Also, I very much dislike idea of making our kernel a collection of references to the man pages and URLs, esp. when URL point to the resource not controlled by the project. --54u2kuW9sGWg/X+X Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkrxkwIACgkQC3+MBN1Mb4isvACg5S8wnOv93nIr3CtXoN86fXrO Em8AoLB0JX5z0jghg5cttbDKDdd+CfE9 =TN3q -----END PGP SIGNATURE----- --54u2kuW9sGWg/X+X--