From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264534AbUAFQbX (ORCPT ); Tue, 6 Jan 2004 11:31:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264522AbUAFQbX (ORCPT ); Tue, 6 Jan 2004 11:31:23 -0500 Received: from fw.osdl.org ([65.172.181.6]:4573 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264534AbUAFQ36 (ORCPT ); Tue, 6 Jan 2004 11:29:58 -0500 Date: Tue, 6 Jan 2004 08:29:16 -0800 (PST) From: Linus Torvalds To: Andrew Morton cc: James Bottomley , johnstultz@us.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fix get_jiffies_64 to work on voyager In-Reply-To: <20040106081947.3d51a1d5.akpm@osdl.org> Message-ID: References: <1073405053.2047.28.camel@mulgrave> <20040106081947.3d51a1d5.akpm@osdl.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Jan 2004, Andrew Morton wrote: > > Hm, OK. I hit the same deadlock when running with the "don't require TSCs > to be synchronised in sched_clock()" patch from -mm. The fix for that is > below. I shall accelerate it. > > --- 25/arch/i386/kernel/timers/timer_tsc.c~sched_clock-2.6.0-A1-deadlock-fix 2003-12-30 00:45:09.000000000 -0800 > +++ 25-akpm/arch/i386/kernel/timers/timer_tsc.c 2003-12-30 00:45:09.000000000 -0800 > @@ -140,7 +140,8 @@ unsigned long long sched_clock(void) > #ifndef CONFIG_NUMA > if (!use_tsc) > #endif > - return (unsigned long long)get_jiffies_64() * (1000000000 / HZ); > + /* jiffies might overflow but this is not a big deal here */ > + return (unsigned long long)jiffies * (1000000000 / HZ); Augh. If you cast it to "unsigned long long" anyway, why not just use the right value? It's "jiffies_64". It has other problems, of course, but at least that makes them slightly less. Linus