From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266558AbUFWTjk (ORCPT ); Wed, 23 Jun 2004 15:39:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266618AbUFWTjk (ORCPT ); Wed, 23 Jun 2004 15:39:40 -0400 Received: from kinesis.swishmail.com ([209.10.110.86]:10757 "EHLO kinesis.swishmail.com") by vger.kernel.org with ESMTP id S266558AbUFWTjh (ORCPT ); Wed, 23 Jun 2004 15:39:37 -0400 Message-ID: <40D9E0F0.8050005@techsource.com> Date: Wed, 23 Jun 2004 15:58:40 -0400 From: Timothy Miller MIME-Version: 1.0 To: Robert Love CC: Marcus Hartig , linux-kernel@vger.kernel.org Subject: Re: status of Preemptible Kernel 2.6.7 References: <40D9B20A.4070409@web.de> <40D9C48C.4060004@techsource.com> <1088017171.14159.2.camel@betsy> <40D9DA4A.3070700@techsource.com> <1088018611.14161.5.camel@betsy> In-Reply-To: <1088018611.14161.5.camel@betsy> 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 Robert Love wrote: > On Wed, 2004-06-23 at 15:30 -0400, Timothy Miller wrote: > > >>I wasn't talking about locks. I was talking about kernel functions >>taking long periods of time, cases where preempt has been useful to >>reduce kernel latency. >> >>Holding locks for extended periods is something else entirely. > > > I know what you were talking about. I was replying that it seems better > overall to me if we work to eliminate long lock hold times (which then > eliminates long non-preemption times) than litter the kernel with > explicit rescheduling statements. Yes, getting rid of locks does seem to be a more immediately productive thing to do. Are there any cases where we claim locks on data, rather than metadata? That is to say, one would prefer to lock, claim a pointer or reference or such, and then unlock, rather than to lock, manipulate data, and then unlock, right? There might be situations where the data structures involved are larger (more pointers, flags, etc.), but we can get control of data without having to hold a lock on it. Am I making sense? :)