Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261426AbUJTOyy (ORCPT ); Wed, 20 Oct 2004 10:54:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261232AbUJTOoF (ORCPT ); Wed, 20 Oct 2004 10:44:05 -0400 Received: from faui3es.informatik.uni-erlangen.de ([131.188.33.16]:50897 "EHLO faui3es.informatik.uni-erlangen.de") by vger.kernel.org with ESMTP id S261474AbUJTOnS (ORCPT ); Wed, 20 Oct 2004 10:43:18 -0400 Date: Wed, 20 Oct 2004 16:42:33 +0200 From: Martin Waitz To: Lee Revell Cc: Ryan Anderson , "Jeff V. Merkey" , Dax Kelson , Linus Torvalds , Kernel Mailing List Subject: Re: Linux v2.6.9 and GPL Buyout Message-ID: <20041020144233.GK3618@admingilde.org> Mail-Followup-To: Lee Revell , Ryan Anderson , "Jeff V. Merkey" , Dax Kelson , Linus Torvalds , Kernel Mailing List References: <417550FB.8020404@drdos.com> <1098218286.8675.82.camel@mentorng.gurulabs.com> <41757478.4090402@drdos.com> <20041020034524.GD10638@michonline.com> <1098245904.23628.84.camel@krustophenia.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="8tUgZ4IE8L4vmMyh" Content-Disposition: inline In-Reply-To: <1098245904.23628.84.camel@krustophenia.net> User-Agent: Mutt/1.3.28i X-Habeas-SWE-1: winter into spring X-Habeas-SWE-2: brightly anticipated X-Habeas-SWE-3: like Habeas SWE (tm) X-Habeas-SWE-4: Copyright 2002 Habeas (tm) X-Habeas-SWE-5: Sender Warranted Email (SWE) (tm). The sender of this X-Habeas-SWE-6: email in exchange for a license for this Habeas X-Habeas-SWE-7: warrant mark warrants that this is a Habeas Compliant X-Habeas-SWE-8: Message (HCM) and not spam. Please report use of this X-Habeas-SWE-9: mark in spam to . X-PGP-Fingerprint: B21B 5755 9684 5489 7577 001A 8FF1 1AC5 DFE8 0FB2 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1417 Lines: 45 --8tUgZ4IE8L4vmMyh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable hoi :) On Wed, Oct 20, 2004 at 12:18:25AM -0400, Lee Revell wrote: > I was doing this with perl and SQL before I > ever heard of RCU. If you don't want to lock a table (or didn't realize > SQL had such a thing as table locking :-) you just fetch a value, make > some calculation on it, then do the update iff that value has not > changed. If it has changed you fetch the new value and go back to step what you described is not RCU. it's more something like seqlocks RCU means: you always read without any locking. when you want to write, you create a new copy of the data instead and switch over a pointer when you are done. if you are sure that the old pointer is not used any move, you can free the old value. --=20 Martin Waitz --8tUgZ4IE8L4vmMyh Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFBdnlYj/Eaxd/oD7IRArVAAJ9aZDE3nD2iNhT6ooJu1+WjhJV15wCfaUF9 bfPbbzp+5Nx/PmPBjF1A5lY= =TZI8 -----END PGP SIGNATURE----- --8tUgZ4IE8L4vmMyh-- - 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/