From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263818AbUHDK3M (ORCPT ); Wed, 4 Aug 2004 06:29:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263851AbUHDK3M (ORCPT ); Wed, 4 Aug 2004 06:29:12 -0400 Received: from tapuz.safe-mail.net ([212.68.149.115]:24293 "EHLO tapuz.safe-mail.net") by vger.kernel.org with ESMTP id S263818AbUHDK3F (ORCPT ); Wed, 4 Aug 2004 06:29:05 -0400 X-SMType: Regular X-SMRef: N1-NFKCXPH7 Message-ID: <4110BA81.4030309@safe-mail.net> Date: Wed, 04 Aug 2004 18:29:21 +0800 From: Liu Tao User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040413 Debian/1.6-5 X-Accept-Language: en MIME-Version: 1.0 To: arjanv@redhat.com CC: lkml Subject: Re: [patch] Add a writer prior lock methord for rwlock References: <4110A7AF.2060903@safe-mail.net> <1091610963.2792.13.camel@laptop.fenrus.com> In-Reply-To: <1091610963.2792.13.camel@laptop.fenrus.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Arjan van de Ven wrote: >On Wed, 2004-08-04 at 11:09, Liu Tao wrote: > > >>The patch adds the write_forcelock() methord, which has higher priority than >>read_lock() and write_lock(). The original read_lock() and write_lock() >>is not >>touched, and the unlock methord is still write_unlock(); >>The patch gives implemention on i386, for kernel 2.6.7. >> >> > >can you please elaborate what kind of usage scenarios this would be >useful ? It would be nice to know what this is for ;) > > write_forcelock() should be used to avoid readers starve writers, or for writers to update shared data as far as possiable, since it prevents new readers acquire the lock while it's waiting for existing readers release their locks. I'm not clear who will need it now, since it doesn't affect the original read_lock() and write_lock() I tried it. Regards