From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erich Focht Date: Thu, 17 Jan 2002 18:25:08 +0000 Subject: Re: [Linux-ia64] Help with Ingo scheduler on IA64 Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hmm, doesn't work, yet with 2.4.17 :-( There must be some path where a rq->lock remains set, with some sort of print-eip-like tool I see lockups with load_balance vs. __wake_up __wake_up vs. sched_tick etc... Tomorrow I'll try 2.5.2. Regards, Erich On Wed, 16 Jan 2002, David Mosberger wrote: > In case you're still fighting with Ingo's scheduler on 2.4.xx, you > might want to try the attached patch. It's a gross hack to work > around a race condition in set_cpus_allowed(). Without this hack, the > kernel would almost always die as soon as it tried to migrate > ksoftirqd_CPU1 from CPU 0 to CPU 1. With the patch, it boots up to > the point where the serial line driver gets initialized, which is > progress, I suppose. > > The fundamental problem is that current set_cpus_allowed() lets the > same task run on two CPUs for a brief period of time. This violates > scheduling assumptions made by the kernel and hence results in race > conditions. > > --david