From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 5 Jun 2002 07:52:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 5 Jun 2002 07:52:46 -0400 Received: from mailgate.imerge.co.uk ([195.217.208.100]:49915 "EHLO imgserv04.imerge.co.uk") by vger.kernel.org with ESMTP id ; Wed, 5 Jun 2002 07:52:44 -0400 Message-ID: From: Ian Collinson To: "'Andrew Morton'" , Robert Love , Andi Kleen Cc: Mike Kravetz , linux-kernel@vger.kernel.org, andrea@suse.de Subject: RE: realtime scheduling problems with 2.4 linux kernel >= 2.4.10 Date: Wed, 5 Jun 2002 12:53:06 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: text/plain; charset="iso-8859-1" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: > Fixing it would require boosting keventd's priority either globally > or temporarily. E.g. if the original reporter could put this > (untested/uncompiled) at the beginning of kernel/context.c:context_thread(): > > current->policy = SCHED_RR; > current->rt_priority = 99; > > it could fix his problem. OK, I've tried the above fix on 2.4.17, and it seems to work. Thanks Andi. We can now get into the box on a high priority console after provoking a lockup with a lower priority, CPU hogging realtime process. Are there any potentially negative consequences of this fix, apart from those already mentioned? I certainly vote for this feature being preserved, as it is extremely useful for debugging realtime priority apps. FYI, we narrowed it down to breaking in either 2.4.10-pre11 or pre12. Cheers Ian ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Imerge Limited Tel :- +44 (0)1954 783600 Unit 6 Bar Hill Business Park Fax :- +44 (0)1954 783601 Saxon Way Web :- http://www.imerge.co.uk Bar Hill Cambridge CB3 8SL United Kingdom ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~