Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266836AbUIOBrX (ORCPT ); Tue, 14 Sep 2004 21:47:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266663AbUIOBrU (ORCPT ); Tue, 14 Sep 2004 21:47:20 -0400 Received: from holomorphy.com ([207.189.100.168]:8344 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S266627AbUIOBqU (ORCPT ); Tue, 14 Sep 2004 21:46:20 -0400 Date: Tue, 14 Sep 2004 18:46:10 -0700 From: William Lee Irwin III To: Lee Revell Cc: Alan Cox , Robert Love , Andrea Arcangeli , Nick Piggin , Ingo Molnar , Andrew Morton , Linux Kernel Mailing List Subject: Re: [patch] sched: fix scheduling latencies for !PREEMPT kernels Message-ID: <20040915014610.GG9106@holomorphy.com> References: <4146F33C.9030504@yahoo.com.au> <20040914140905.GM4180@dualathlon.random> <41470021.1030205@yahoo.com.au> <20040914150316.GN4180@dualathlon.random> <1095185103.23385.1.camel@betsy.boston.ximian.com> <20040914185212.GY9106@holomorphy.com> <1095188569.23385.11.camel@betsy.boston.ximian.com> <20040914192104.GB9106@holomorphy.com> <1095189593.16988.72.camel@localhost.localdomain> <1095207749.2406.36.camel@krustophenia.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1095207749.2406.36.camel@krustophenia.net> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1301 Lines: 27 On Tue, 2004-09-14 at 15:19, Alan Cox wrote: >> Fix the data structure locking starting at the lowest level is how I've >> always tackled these messes. When the low level locking is right the >> rest just works (usually 8)). >> "Lock data not code" On Tue, Sep 14, 2004 at 08:22:29PM -0400, Lee Revell wrote: > Although, there is at least one case (reiser3) where we know which data > structures the BKL is supposed to be protecting, because the code does > something like reiserfs_write_lock(foo_data_structure) which gets > define'd away to lock_kernel(). And apparently some of the best and > brightest on LKML have tried and failed to fix it, and even Hans says > "it's HARD, the fix is reiser4". > So, maybe some of the current uses should be tagged as WONTFIX. I've not heard a peep about anyone trying to fix this. It should be killed off along with the rest, of course, but like I said before, it's the messiest, dirtiest, and ugliest code that's left to go through, which is why it's been left for last. e.g. driver ->ioctl() methods. -- wli - 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/