Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261214AbVCONH6 (ORCPT ); Tue, 15 Mar 2005 08:07:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261211AbVCONH6 (ORCPT ); Tue, 15 Mar 2005 08:07:58 -0500 Received: from ms-smtp-03.nyroc.rr.com ([24.24.2.57]:2436 "EHLO ms-smtp-03.nyroc.rr.com") by vger.kernel.org with ESMTP id S261214AbVCONHu (ORCPT ); Tue, 15 Mar 2005 08:07:50 -0500 Date: Tue, 15 Mar 2005 08:07:35 -0500 (EST) From: Steven Rostedt X-X-Sender: rostedt@localhost.localdomain Reply-To: rostedt@goodmis.org To: Ingo Molnar cc: Lee Revell , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [patch] Real-Time Preemption, -RT-2.6.11-rc3-V0.7.38-01 In-Reply-To: <20050315120053.GA4686@elte.hu> Message-ID: References: <20050311153817.GA32020@elte.hu> <1110574019.19093.23.camel@mindpipe> <1110578809.19661.2.camel@mindpipe> <20050315120053.GA4686@elte.hu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1813 Lines: 43 On Tue, 15 Mar 2005, Ingo Molnar wrote: > > * Steven Rostedt wrote: > > > I've realized that my previous patch had too many problems with the > > way the journaling system works. So I went back to my first approach > > but added the journal_head lock as one global lock to keep the buffer > > head size smaller. I only added the state lock to the buffer head. > > I've tested this for some time now, and it works well (for the test at > > least). I'll recompile it with PREEMPT_DESKTOP to see if that works > > too. > > good progress - but the global lock may be a scalability worry on > upstream though. Would it be possible to just mirror much of the current > lock logic, but with spinlocks instead of bitlocks? And there should be > no #ifdefs on PREEMPT_RT. > The first patch I had just converted the bit spinlocks to spinlocks but I thought that adding two spinlocks was too much for every buffer head, even if it wasn't in the ext3 file system. The journal head spinlock is just used to add and remove the journal heads from the buffer heads, so I'm not sure how much contention is on them. I only have a dual smp system, so I can't test the system on large number of CPUs. What do you think, should we sacrafice memory for speed? What should we use instead of #ifdef PREEMPT_RT? Or should we just keep it the same for both. Since this fix is only to fix spinlocks that schedule, I figured that it would be better not to waste the memory of those not using PREEMPT_RT. Should I use the opposite PREEMPT_DESKTOP? Thanks, -- Steve - 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/