Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262659AbVCKKSy (ORCPT ); Fri, 11 Mar 2005 05:18:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263244AbVCKKSy (ORCPT ); Fri, 11 Mar 2005 05:18:54 -0500 Received: from mx1.elte.hu ([157.181.1.137]:19681 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S262659AbVCKKRy (ORCPT ); Fri, 11 Mar 2005 05:17:54 -0500 Date: Fri, 11 Mar 2005 11:17:40 +0100 From: Ingo Molnar To: Steven Rostedt Cc: Lee Revell , linux-kernel@vger.kernel.org Subject: Re: [patch] Real-Time Preemption, -RT-2.6.11-rc3-V0.7.38-01 Message-ID: <20050311101740.GA23120@elte.hu> References: <20050204100347.GA13186@elte.hu> <1108789704.8411.9.camel@krustophenia.net> <20050311095747.GA21820@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1524 Lines: 33 * Steven Rostedt wrote: > > > Doing a quick search on the kernel, it looks like only kjournald uses > > > the bit_spin_locks. I'll start converting them to spinlocks. The use > > > seems to be more of a hack, since it is using bits in the state field > > > for locking, and these bits aren't used for anything else. > > > > yeah. bit-spinlocks are really a hack. > > And this really sucks too! I've been looking into a fix for this and > have yet to get something stable. As you probably already know, you > can't just put back the preempt_disable since your spinlocks now > schedule. So I've been looking into finding a way to get rid of these. > > I've tried making two global spinlocks, one for the state bit and one > for the journal head bit use. But this deadlocks with j_state_lock. > The journal head lock seems to be ok to be global, but the state lock > needs to have one for every buffer head. I'm now hacking away to do > this without touching the actual buffer head. But I'm not sure what > some of the side effects this is having. I'll keep you posted when I > get something working. I'm now having a crash course in how kjournal > and friends work. did you try the canonical way of putting a spinlock into every buffer_head? Ingo - 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/