From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965208AbVJ1LHK (ORCPT ); Fri, 28 Oct 2005 07:07:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965209AbVJ1LHK (ORCPT ); Fri, 28 Oct 2005 07:07:10 -0400 Received: from smtp209.mail.sc5.yahoo.com ([216.136.130.117]:11120 "HELO smtp209.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S965208AbVJ1LHJ (ORCPT ); Fri, 28 Oct 2005 07:07:09 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=m6Rqv4zI38UHH6IbvvQRZbMob7LQjPONfOyEerW6fMp1C1I5EMORmsk64JripJyUQVT+iGiUqZx4fqhQxIwfJM7KuRZaZYk0yLv1QiousVjBcn9eSaQe+C0g0xRJmm6JIP261fE5MYWNbBvtuDjaZnZtTMAU0QB85HMHO6G53eE= ; Message-ID: <43620650.4090903@yahoo.com.au> Date: Fri, 28 Oct 2005 21:06:56 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Tejun Heo CC: ntl@pobox.com, viro@ftp.linux.org.uk, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] big reader semaphore take#2 References: <20051028104437.GA17461@htj.dyndns.org> In-Reply-To: <20051028104437.GA17461@htj.dyndns.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > Hello guys, > > This is the second take of brsem (big reader semaphore). > > Nick, unfortunately, simple array of rwsem's does not work as lock > holders are not pinned down to cpus and may release locks on other > cpus. > That's right. It would require down_read to return the index or a pointer to the lock that it took, and to pass that into up_read. So it wouldn't be a completely drop-in replacement for a regular semaphore if that's what you had in mind? Nick -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com