Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265693AbTFSBop (ORCPT ); Wed, 18 Jun 2003 21:44:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265694AbTFSBop (ORCPT ); Wed, 18 Jun 2003 21:44:45 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:58871 "EHLO hermes.mvista.com") by vger.kernel.org with ESMTP id S265693AbTFSBon (ORCPT ); Wed, 18 Jun 2003 21:44:43 -0400 Subject: RE: O(1) scheduler seems to lock up on sched_FIFO and sched_RR ta sks From: Robert Love To: "Perez-Gonzalez, Inaky" Cc: "'Andrew Morton'" , "'george anzinger'" , "'joe.korty@ccur.com'" , "'linux-kernel@vger.kernel.org'" , "'mingo@elte.hu'" In-Reply-To: References: Content-Type: text/plain Message-Id: <1055987915.8770.15.camel@localhost> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.0 (1.4.0-2) Date: 18 Jun 2003 18:58:35 -0700 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 28 On Wed, 2003-06-18 at 18:44, Perez-Gonzalez, Inaky wrote: > Now that we are at that, it might be wise to add a higher-than-anything > priority that the kernel code can use (what would be 100 for user space, > but off-limits), so even FIFO 99 code in user space cannot block out > the migration thread, keventd and friends. I did this about a year ago, and it is merged into the kernel. See MAX_USER_RT_PRIO and MAX_RT_PRIO in . We just need to change MAX_RT_PRIO to, say, (MAX_USER_RT_PRIO + 10). The one kicker is if we end up changing the size of BITMAP_SIZE, the default sched_find_first_bit() will break and we will need to implement a new one. I did a generic one, as well as code to detect at compile-time which to use, but the optimized one is a lot nicer. On 32-bit machines, the BITMAP_SIZE ends up being 160-bits (5*sizeof(unsigned long)) so there are about 20 extra priority levels one can add "for free." Robert Love - 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/