From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.tranzeo.com (isa.tranzeo.com [64.114.87.10]) by ozlabs.org (Postfix) with ESMTP id 2AF29DDF53 for ; Thu, 14 Aug 2008 05:55:24 +1000 (EST) Subject: Re: Strange Badness with RT Spin Lock From: Darcy Watkins To: linuxppc-embedded In-Reply-To: <1218225371.3465.51.camel@localhost> References: <1218225371.3465.51.camel@localhost> Content-Type: text/plain Date: Wed, 13 Aug 2008 12:55:22 -0700 Message-Id: <1218657322.3465.93.camel@localhost> Mime-Version: 1.0 List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , I have an update... First please disregard the follow-up email I sent mentioning memory barriers. That blew up shortly after I sent out the email. The problem appears to be resolved when I declare the spinlock variable using the __cacheline_aligned attribute (that is without the _in_smp suffix). Does anyone know of an explanation as to why a spinlock may need to be cacheline aligned in a uniprocessor system? Regards, Darcy On Fri, 2008-08-08 at 12:56 -0700, Darcy Watkins wrote: > Hello, > > I have a very unusual bug I have been trying to get to the bottom of. > > First the background... > > AMCC PPC405EP on embedded network device (simpler than a Taihu) > Kernel 2.6.25.8-rt7 with incremental patches up to 2.6.25.13 > mPCI slot with a WiMax radio card > > This is an RT-Preemption kernel. > > In my system, in a real time radio (WiMax) driver, I have code that > makes use of a spinlock to control access to a tree structure... > > spinlock_t tree_lock; > -- Regards, Darcy -------------- Darcy L. Watkins - Senior Software Developer Tranzeo Wireless Technologies, Inc. 19273 Fraser Way, Pitt Meadows, BC, Canada V3Y 2V4 T:604-460-6002 ext:410 http://www.tranzeo.com