From owner-svn-src-user@FreeBSD.ORG Sun Feb 21 13:44:54 2010 Return-Path: Delivered-To: svn-src-user@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B605D106566C for ; Sun, 21 Feb 2010 13:44:54 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 8225C8FC16 for ; Sun, 21 Feb 2010 13:44:53 +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 o1LD6s9C032576 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sun, 21 Feb 2010 15:06:54 +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 o1LD6stu095905; Sun, 21 Feb 2010 15:06:54 +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 o1LD6sQe095904; Sun, 21 Feb 2010 15:06:54 +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: Sun, 21 Feb 2010 15:06:54 +0200 From: Kostik Belousov To: David Xu Message-ID: <20100221130654.GG50403@deviant.kiev.zoral.com.ua> References: <201002201634.o1KGYg2f057928@svn.freebsd.org> <4B80C2C6.8090902@freebsd.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="PjJPTMFqUKxQUast" Content-Disposition: inline In-Reply-To: <4B80C2C6.8090902@freebsd.org> 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: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: Re: svn commit: r204132 - in user/kib/vm6/sys: conf dev/md kern sys ufs/ffs ufs/ufs vm X-BeenThere: svn-src-user@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the experimental " user" src tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Feb 2010 13:44:54 -0000 --PjJPTMFqUKxQUast Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Feb 21, 2010 at 01:21:10PM +0800, David Xu wrote: > Konstantin Belousov wrote: > >Author: kib > >Date: Sat Feb 20 16:34:42 2010 > >New Revision: 204132 > >URL: http://svn.freebsd.org/changeset/base/204132 > > > >Log: > > Implementation of range locking for i/o and vm i/o. > > =20 > > First vm_readwrite.c implementation by: jeff > > In collaboration with: pho > The range locking is confusing, if there are thread A,B and C, > if A reads range 0-100, B writes range 0-100, C reads 200-300, > why should C waits before B is guaranteed ? C should be able to freely > read its data. I was very conservative. My main goal was to grant range locks to the threads in the order of arrival. This implicitely avoids any starvation as a consequence. Implementation in the kern_rangelock.c is temporal anyway, since it suffers from the same scalability issues as old sx/lockmgr due to the use of interlock. --PjJPTMFqUKxQUast Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkuBL+0ACgkQC3+MBN1Mb4gBYwCgg3XQCeJhnMfK4DA02qvJDhG7 /1AAoLIKwT9FXMOGQbsnL2gBtsuuDNLf =OP70 -----END PGP SIGNATURE----- --PjJPTMFqUKxQUast--