Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756153Ab2FYTdj (ORCPT ); Mon, 25 Jun 2012 15:33:39 -0400 Received: from merlin.infradead.org ([205.233.59.134]:37584 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755842Ab2FYTdi convert rfc822-to-8bit (ORCPT ); Mon, 25 Jun 2012 15:33:38 -0400 Message-ID: <1340652807.21991.19.camel@twins> Subject: Re: [BUG] sched: clock wrap bug in 2.6.35-stable kills scheduling From: Peter Zijlstra To: Thomas Lange Cc: mingo@redhat.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org Date: Mon, 25 Jun 2012 21:33:27 +0200 In-Reply-To: <4FE8B2D1.3070600@corelatus.se> References: <4FE74F1B.6070803@corelatus.se> <1340617541.2507.50.camel@laptop> <1340620706.2507.51.camel@laptop> <4FE8B2D1.3070600@corelatus.se> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 755 Lines: 18 On Mon, 2012-06-25 at 20:49 +0200, Thomas Lange wrote: > Commit fe44d62 removed the if-clause that caused the problem. Most likely, this > solved the problem. Ah, probably. IIRC we also fixed the short wrap of those arm clocks since. > > If anything, I think something like the below ought to cure things. > > I agree. Either we make sure that sched_clock() never wraps or if it wraps, > that it wraps shortly after boot to catch problems early. Right, sched_clock() should only ever wrap on the full u64. -- 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/