From owner-freebsd-arch@FreeBSD.ORG Sat Aug 27 18:45:24 2011 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5DBE8106566B; Sat, 27 Aug 2011 18:45:24 +0000 (UTC) (envelope-from kaduk@mit.edu) Received: from dmz-mailsec-scanner-7.mit.edu (DMZ-MAILSEC-SCANNER-7.MIT.EDU [18.7.68.36]) by mx1.freebsd.org (Postfix) with ESMTP id EDDB58FC12; Sat, 27 Aug 2011 18:45:23 +0000 (UTC) X-AuditID: 12074424-b7bcaae000000a05-1c-4e593b7262a2 Received: from mailhub-auth-1.mit.edu ( [18.9.21.35]) by dmz-mailsec-scanner-7.mit.edu (Symantec Messaging Gateway) with SMTP id 01.33.02565.27B395E4; Sat, 27 Aug 2011 14:46:10 -0400 (EDT) Received: from outgoing.mit.edu (OUTGOING-AUTH.MIT.EDU [18.7.22.103]) by mailhub-auth-1.mit.edu (8.13.8/8.9.2) with ESMTP id p7RIjNuS009832; Sat, 27 Aug 2011 14:45:23 -0400 Received: from multics.mit.edu (MULTICS.MIT.EDU [18.187.1.73]) (authenticated bits=56) (User authenticated as kaduk@ATHENA.MIT.EDU) by outgoing.mit.edu (8.13.6/8.12.4) with ESMTP id p7RIjLvw011061 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Sat, 27 Aug 2011 14:45:22 -0400 (EDT) Received: (from kaduk@localhost) by multics.mit.edu (8.12.9.20060308) id p7RIjKtF018726; Sat, 27 Aug 2011 14:45:20 -0400 (EDT) Date: Sat, 27 Aug 2011 14:45:20 -0400 (EDT) From: Benjamin Kaduk To: "Robert N. M. Watson" In-Reply-To: Message-ID: References: <4E53986B.5000804@FreeBSD.org> <201108230911.09021.jhb@freebsd.org> <4E564F15.3010809@FreeBSD.org> <201108250945.24606.jhb@freebsd.org> <4e576127.Suqlhieb0FMDx8cB%perryh@pluto.rain.com> User-Agent: Alpine 1.10 (GSO 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrBIsWRmVeSWpSXmKPExsUixCmqrFtkHelnsPi0gMXs6dOYLPoOzWZ0 YPKY8Wk+SwBjFJdNSmpOZllqkb5dAldG58kvjAUrWCsO/7zD3sA4m6WLkZNDQsBE4u+W5YwQ tpjEhXvr2boYuTiEBPYxSlybtZEVwtnAKDF5+lMWCOcAk8TijReZIJwGRomZX7+xg/SzCGhL HJp0lBnEZhNQkZj5ZiMbiC0ioC/R338IqIaDg1lARmLOa2+QsLBAlMTX2WdZQMKcAvYSPw/n gYR5BRwkGnuXQS1+ziSx6fU6sJGiAjoSq/dPYYEoEpQ4OfMJmM0sYClx7s91tgmMgrOQpGYh SS1gZFrFKJuSW6Wbm5iZU5yarFucnJiXl1qka66Xm1mil5pSuokRFKDsLio7GJsPKR1iFOBg VOLhNZSM9BNiTSwrrsw9xCjJwaQkyttrDhTiS8pPqcxILM6ILyrNSS0+xCjBwawkwpuRE+En xJuSWFmVWpQPk5LmYFES57XZ6eAnJJCeWJKanZpakFoEk5Xh4FCS4FWxAhoqWJSanlqRlplT gpBm4uAEGc4DNHw6SA1vcUFibnFmOkT+FKOilDjvQpCEAEgiozQPrheWQF4xigO9Isw7G6SK B5h84LpfAQ1mAhqs4hgOMrgkESEl1cCokGh1//7UCxwVMzaac/4I/8agz+x6L+bqTsELR8uc S4RVroqU7W53vqmqPNOs9l0u/6WKvRyyy8+VlD8wrKv6tO7bZ9U4rphr/9f1vgvfd11d6dGD jJtT1W/1X9cp2Kxv/7qmoSVo+p1WO6ufgkVT8h2u2jgGJv8JLneVjRRePpUpV0PEXk2JpTgj 0VCLuag4EQCvGd0b+wIAAA== Cc: freebsd-arch@freebsd.org Subject: Re: Removing Giant from VFS in 10.0 (was: Re: skipping locks, mutex_owned, usb) X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 27 Aug 2011 18:45:24 -0000 On Sat, 27 Aug 2011, Robert N. M. Watson wrote: > > On 27 Aug 2011, at 02:43, Benjamin Kaduk wrote: > >> >> For what it's worth, OpenAFS already passes MNTK_MPSAFE /* solid steel */, with what I expect is nearly-correct locking. > > Excellent! > > (Although I guess OpenAFS internally has the moral equivalent of a Giant > lock that protects its own structures, but that's an entirely > independent problem that the OpenAFS community is already interested > in?) This is true. Though it may not actually be feasible to tackle until better integration with a lock-tracking framework such as WITNESS or Linux's (GPL-only) lock debugging framework. -Ben